Despite all the pithy bumper sticker jokes about “Save Water, Drink Beer!” the truth is that brewing beer is a terribly inefficient and water wasteful process. Between growing, cleaning, mashing, sanitizing, chilling — it takes many, many times the volume of water as beer produced. 

The usual rule of thumb is 7:1 water-to-beer. In other words, it takes 7 gallons of water to produce 1 gallon of beer (or 7 L water to 1 L beer). A decade ago, MillerCoors made big waves and received accolades by achieving a 3.8:1 ratio while brewing.¹ 

To a large brewery, water efficiency equals a large cost savings. And while it may not be as big a deal for us homebrewers, who doesn’t want to save money? And that’s before you even consider the ecological advantages. 

For Drew, that concern lives at the front of his mind because drought is never far away in Southern California. There’s very little sense in being any more needlessly profligate than we already are. He’s ripped up most of his water-thirsty grass, but still modern “comfortable” life isn’t mindful. Even Denny, in what most would think of as “damp Oregon” is experiencing “exceptional drought” conditions. 

While we homebrewers will probably never hit the highs (or lows?) of MillerCoors’ achievements, there are a few fairly simple and easy things to do to cut down our water usage. These start with reducing water needs, being more efficient with water, and reusing it. Let’s go through each in more detail.

Reduce Your Needs Before You Begin

Homebrewing tends to be a muscle memory rote activity. “Fill the vessel up yea high,” “Rinse with this much water,” “Make this much beer.” But as both of us have gotten older there’s a time to stop and think — do I really need to make 5–10 gallons (19–38 L) of this beer? The answer often turns out — not really. Better to truly focus on the volume you need and waste less beer, ingredients, and water in the process.

You can also reduce your overall water needs by making an extract batch or two. We’ve said it many times before that extract beer’s “bad” reputation isn’t the ingredients’ fault — it’s the inexperienced brewer with no clue how to manage a ferment or sanitize things correctly! Bonus points for a shorter brew day as well.

Be Efficient with Your Cleaning

Cleaning is one of the biggest water and energy spends in brewing. It’s absolutely vital — you won’t catch us pulling that old cheap brew guy mantra of “I’ve never cleaned my plastic buckets and my beer tastes fine.” For our best beer and use of our time, we must keep clean.

You can make your cleaning more water efficient by getting things cleaned early on. Empty a fermenter or a keg? Get that puppy rinsed before things dry and get glued into place! You’ll need much less effort and water to get things done that way. (And maybe rinsing your beer glass with another beer counts — or maybe that’s too much of that crusty old guy logic!)

The efficiency of cleaning, like all chemical reactions, is driven by factors like concentration, temperature, and agitation. We don’t recommend dosing twice your cleaners’ directions, that will just lead to more rinsing and other nasty side effects. It is, however, true that a little extra heat (not enough to melt your plastic) can help along with physical agitation, be it scrubbing or other motion. If you don’t want to scrub, you could look at a semi-professional solution like all the various pump and spray ball gadgets out there to keep your cleaner moving.

Along the same line of thought, not everything needs to be completely immersed in cleaner or sanitizer to get the job done. In fact, the only time that Drew uses a full volume of anything is when sanitizing kegs. He uses a full volume of Sani-Clean so that when he pushes it out via CO₂ it makes his kegs well purged of oxygen.

Also, we know that it’s hard to resist, but as long as you’re using a no-rinse sanitizer in proper concentrations — don’t rinse! Those foamy bubbles aren’t going to impact your beer.

In terms of efficiency, it’s hard to beat the idea of stacking things up and doing stuff in a row. This is easy assuming you’ve rinsed your kegs/carboys/fermenters and got a stack of things to go through. For Drew, he’ll stack kegs up by the fours, roughly, and then run the kegs in sequence. Using a single batch of cleaner or sanitizer to get through everything is just a smart plan.

Chill Out to Save  

Outstripping all other uses of water during the brew day is the final act: The chilling. Turns out that it takes a fair amount of water to take a batch of beer from near boiling to pitching temperatures. 

And we can’t talk about saving water and chilling without first mentioning the easiest way to reduce water usage — embrace the no-chill methodology and don’t chill! While it may feel outrageous in the face of every “good modern practice,” you should remember that force chilling beer is a relatively new practice in the history of beer making. And before quick chilling, lager brewers used coolships and Baudelot chillers to brew clean beer. The notion that coolships are only for funky beers is bunk, as the history of Pilsner-style beer clearly shows.

You don’t have to embrace the full funk life and emulate lambic brewers with shallow trays allowing overnight chilling (and partial addition of wild yeasts and bacteria). You can follow the modern examples from Australia and use a 5-gallon (19-L) HDPE water cube. Fill the clean cube with the hot wort, push out any excess air, and cap it. Let the wort cool naturally overnight in its relatively safe hot pack state. When cooled, pour the cube into a fermenter and pitch your yeast. What you need to keep in mind when doing this is the amount of time your hops will be in contact with hot wort. Drew usually treats everything like it’s been boiled for 30 minutes longer than it was in the kettle — so for a hop addition intended for boiling 60 minutes, he’ll add the hops at the 30-minute mark (while maintaining the full length of the boil). And before you go “but, but that will make terrible beer,” we enjoyed a great number of Australian homebrews made this way on our trip there a few years back and they were great beers!

When chilling the beer, look at how far and fast you can go with the least amount of water. If you have a way to chill your fermenter, you don’t even need to chill the batch all the way. We both have glycol-chilled fermenters, but Drew doesn’t have Denny’s stupidly cold well water, instead dealing with tap water at temperatures in the 70s (low- to mid- 20s °C) during a SoCal summer.

Since chilling becomes less effective as the wort temperature approaches the chilling water temperature, Drew doesn’t even try and get the wort below 90 °F (32 °C) during the summer. Instead, once the tap water significantly slows cooling of the wort, he transfers the wort to his sanitized fermenter and starts the cooling jacket. With 24 °F (-4 °C) glycol flowing around the beer, it’s typically to low 60s °F (16–17 °C) pitching temperature in 30 minutes or so — just enough time to finish the cleanup!

Or, if you choose to pitch a kveik yeast, after chilling to 90 °F (32 °C) you’re done — pitch and start your cleanup.

If you’re dead set on your wort being chilled as soon as possible, you can improve the temperature differential of water vs. wort by taking a cue from professional breweries with their cold liquor tanks. Refrigerate a sizable volume of water ahead of time and then use a submersible pump (or put the water in kegs and push it). 

If you’re using an immersion chiller, chill the beer first with your tap water and then as chilling slows down (~100–120 °F/38–49 °C), switch to the chilled water to drive the chilling to its conclusion. Stirring, recirculating with a pump, or even just lifting the coil periodically will also greatly improve your chilling time as you break up the layer of cooler wort that develops around the coils.

If you’re using a counterflow chiller, you can do what Drew used to do back in the day and send the output of the chiller (on tap water) into a simple immersion coil sitting in a bucket of ice water and then from there to the fermenter. And to that point, ice is your friend. If you don’t want to mess around with large volumes of water in a fridge, just make a big ice bath and use that. One of Drew’s friends in his homebrew club owns a giant ice machine and uses its output to drive his brews to completion.

Again, the whole point is to get the temperature differential as high as you can for as long as you can to get your beer chilled faster and use less water. If you’re very technically adept and have a fairly sizable glycol chiller, you could force circulate cold glycol through the chiller to drop the temperature. However, the typical homebrew-sized chiller is inadequate for this purpose and it’s much simpler to run water/ice water and then chill down with refrigeration or a big water bath.

Don’t Run Down the Drain

After you’ve found ways to reduce water consumption, the last thing to think about is reusing/recycling it, which is fairly easy. As you’re chilling, capture the water and save it for another use. The first good reason to do this is to actually get a sense of how much water you’re using. It’s incredibly important to know just how much water you’re running out to know whether or not you’re making improvements. 

If you’re a hardcore dedicated brewer, the easy answer about what to do with the water is make another batch of beer! Just about any brewery that’s wanting to save money and sewer bills will capture their chilling output and save it for the next batch of beer. This is easy to do when your next brew day is tomorrow, so it’s often not the most practical step for homebrewers — but keep it in mind. Bigger brewers on 24/7 brew cycles will actually take advantage of the heating of the chilling water to get the next batch going with less delay. Assuming you’re not brewing another batch yet, look around at your household to-do list and find places that you can reuse the water.

• Clean the brew gear. Your mash tun won’t clean itself! Don’t you have kegs or bottles that need a once over?

• Fill your laundry machine — works great with top loaders.

• Wash the cars/dogs/cats/horses/pygmy elephants/kids.

• Fill your pool or pond.

• Let it cool and water the lawn/garden/house plants.

OK, these are just a few thoughts about water efficiency with brewing. No, we’ll never be as ruthlessly efficient as the big guys. We don’t have the same motivation and return on our efficiency and no one is pretending that doing all of these steps will save the environment for humanity, but a great many of these things are simple to implement and can save you time (no-chill/refrigeration after chilling part way), some will even scratch that gamer and engineer’s min-maxing itch as you try and set a land speed record for chilling a batch of beer! 

Reference:
¹ Walsh, B. (2013) “At the farm and the brewery, MillerCoors gets more beer to the barrel with water efficiency.” Time. Available at: https://shorturl.at/8Gmcu

We return to water this issue because as it turns out, the composition of your water, being more than 90 percent of your beer, is incredibly impactful on the final nature of your beer. Most brewers will forgo messing with their water early in the hobby — first out of not knowing that it’s important and then believing the topic is too complicated for the impact it has — before finally trying to crack the H₂O molecule. We firmly believe that adjusting water to fit a certain profile to complement the beer style being brewed is worth the time it takes to understand this subject.

Manipulating your water profile is often the last piece that pushes someone’s beer from “pretty good” to “hot damn.” But we understand why people don’t tackle it. Water chemistry is intense stuff. Unlike many other parts of brewing, the science is much harder to wave away behind a magical calculator because there are interactions upon interactions, upon interactions. And it all starts with reading a water report. 

Fun fact: In the U.S., your water district is required to test and report on the quality of the water they feed into your local system. No matter how big or small, they are also required to make that reporting available to the public (though, as we’ll discuss later, these reports aren’t always as helpful as you’d assume as water sources may change throughout the year). Turns out that knowing what’s in your water is important to more than just brewing. As brewers starting with the water available in your household, these water reports should be used to make decisions in how you treat your brewing water.

Water Reminders

Before we dig into the nature of water reports and how to use them to tell you something useful, here are some fundamental water rules that the two of us follow:

Your brewing water should taste clean with no off-flavors, sulfur, metals, etc.

If you do nothing else to your water, remove any chlorine or chloramine from it. (Unless you’re on a well, odds are good your water has one of those compounds. Either slow carbon filter (under 1 gallon/4 L per minute) or a pinch of metabisulfite powder will do the trick.

When choosing a water profile, we skip “city profiles” and prefer to go on profiles based on beer color (pale, amber, brown, black) and malt balance (dry, balanced, full). See Table 1 on the facing page for good starting points for different types of beers.

Don’t obsess over trying to dial in numbers to match a target water profile. No matter what your favorite water calculator tells you, your additions do not need to be that precise and perfect. 

Use your salts for flavor (and basic chemistry). 50 ppm of calcium and under 50 ppm of sodium are generally safe rules of thumbs. Don’t try and dial in your pH with calcium additions!

Don’t go overboard with your salt additions. Keep additions simple and your numbers in reasonable ranges — you’ll mostly just need small touches of gypsum and calcium chloride.

Use lactic or phosphoric acid to adjust your mash pH.

On to the Water Report

As we said earlier, your water provider is required to publish reports on water quality and these days they’re invariably online. Search for your water provider and “annual water reports.” Odds are pretty good you’ll get a clear result. 

Example

Drew Googling “Pasadena DWP water report” returns: https://pwp.cityofpasadena.net/waterqualityreports/ where the Department of Water and Power has reports available going back to 2001. 

Caveat

Be aware that these water reports are essentially averages of what’s happening in your water area and not a guarantee that the water pouring out of your taps has the exact same profile. In fact, in a number of places, the water profiles will change over the year as water sources are added, removed, and blended. (The water profile in Los Angeles dances between soft Sierra snow melt and mineral-laden Colorado River water, amongst other sources.) In fact, some areas may have different water sources from one day to another, in which case relying entirely on a water report may be far off from your actual water at any given time. If you want something more precise, read on, but in most cases your water report averages will provide you a general starting ground.

Pull up your water report. Find the longest version they offer. Everything we care about as brewers is generally buried in tables called names like “Secondary Standards” and “Other Parameters.” These are characters that aren’t health and safety motivated (like lead, uranium, etc.), but instead taste, flavor, and odor motivated.

For most brewing applications, what we are trying to find is water pH, alkalinity, calcium, magnesium, sodium, chloride, sulfate, and perhaps total hardness and bicarbonate (these last two can be back calculated from other values). Total hardness is generally a measure of calcium and magnesium. 

By the by, don’t get fooled into thinking “hard water is bad for brewing.” There are plenty of ways and styles to brew with hard water. What we mostly will care about is getting our mash pH into the right range and adjusting those salts to impact our flavors.

In those tables, many of the needed numbers are directly expressed in parts per million (ppm) or mg/L. Plug those straight into your favorite water calculator of choice. (We use Bru’n Water, plus the calculators in Brewfather and Grainfather — the later two are fairly straightforward but Bru’n Water is the most accurate and flexible once you’re configured. Go listen to Episode 45 of the Brew Files if you want
to hear a guided tour of setting it up, available at www.experimentalbrew.com/2018/09/19/brew-files-episode-45-water-water-everywhere.  

It is critical you pay attention to the listed units on both your water report and your calculator. The numbers aren’t always plug and play. In particular, pay attention to the units around total hardness, bicarbonate, and alkalinity as they get expressed in different ways by different reports. For instance, both hardness and alkalinity get reported as “mg/L (or ppm) as calcium carbonate CaCO₃,” but not always. Sometimes sulfate gets reported as SO₄-S instead of just SO₄. Why this matters is Brewfather wants SO₄-S, where Bru’n Water wants SO₄. 

The maddening part about water reports is they don’t always have things listed as you need, but modern calculators can generally help you out. Alkalinity is one that used to be difficult to find, but in a recent survey appears to be more common now. With most of the facts in hand, your water calculator can help you reverse engineer and double check your values. The software should report a value of how closely the cations (calcium, magnesium, sodium, etc.) and anions (bicarbonate, carbonate, chloride, sulfate, etc.) balance chemically and warn you if you’re too far afield.

Additionally, don’t hesitate to reach out to your water company and ask them “can you give me a hand?” You may be surprised at how much information a polite request will garner you. Stuff that’s not listed in the water report may actually be tracked.

But what if you’re on a well, like Denny? At that point, you’re going to need to generate your water profile. There are brewing oriented test kits like LaMotte’s BrewLab or Sensafe’s eXact iDip. You can feel like a kid with a chemistry set all over again! Or if you want something more precise (and this goes for those with water district reports as well), order a W-501 Brewers’ Test from Ward Labs (www.wardlab.com/). It costs about the same as a batch of beer, but it tells you precisely what’s coming out of your taps at the time.

One nice bit of handiness about that Ward report is that it’s become such an industry standard that most water calculators directly tell you how to input the water report. If you’re truly serious about adjusting your water, a lab report is well worth the investment. The precision in these reports is superior to the average rates reported by municipalities. See Table 2 above with some real numbers and see how far off some can be.

If you use reverse osmosis (RO) or distilled water, your water profile, assuming that the filtration systems are properly maintained and functional, is effectively zeros across the board. (You’ll definitely want to confirm this with a total dissolved solids tester.) And if you’re using “spring water” or “drinking water,” check out the source company — they too might have a water report you can use as well. 

If you really want to dig in deeper on water, but not as deep as Water by John Palmer and Colin Kaminski, we’d recommend reading the basic tutorials at brunwater.com and Kai Troester’s water tutorial at braukaiser.com 

Mash chemistry is one of those final pieces of the brewing puzzle that many homebrewers, and even some pros, choose to ignore. Perhaps they think it is too complicated. Or maybe they are just lazy. Either way, it’s a shame because all-grain brewers brew their best beer with at least a basic understanding of how grains, minerals, and acids affect mash pH. It’s also fairly simple once the basics are understood — no chemistry degree required! Though, of course, it certainly wouldn’t hurt.

You might recall from high school chemistry that pH is a logarithmic scale that expresses the alkalinity or acidity of a substance. pH is considered neutral at 7. A solution under pH 7 is considered acidic, while over pH 7 is considered alkaline. 

Distilled water clocks in at pH 7 right out of the distillation process, but as it picks up CO₂ from the atmosphere, its pH will drop to around 6.5 because CO₂ is acidic. Dissolved minerals can likewise lower or raise the pH of water. Dissolved minerals are the primary driver of water’s pH. The pH of most municipal water will hover between 6.5 and 8.5, determined mainly by dissolved minerals.

However, the pH of water is of minor importance to brewing. What’s important is the mash pH, which can change drastically depending on the grist bill.

When we add pale malt to our brewing water, it will lower the pH because pale malt is mildly acidic. Mashing pale malt with almost any potable water source will lower the mash into the pH 5–6 range. Most likely, it will drop the range between 5.4–5.8. And that’s great! Because this is within the enzymatic conversion range. Practically, that’s all you have to do: Mix your grain with hot water, and mashing will take care of itself. Voila!

But, if we want to make the best beer possible, the range of pH we are looking for is a bit narrower — for most light beer, we are looking for a pH range of about 5.2–5.4, and for most dark beer, we are looking for a range between 5.4–5.6.

As mentioned, pale malt is mildly acidic, so when mixed with water it lowers the pH. Darker malt, especially roasted malt, is even more acidic. Combining a 100% Pilsner malt grist with distilled water will give us a pH of about 5.75. If we mix a stout grist with lots of roasted malts in distilled water, our pH may drop below 5 because of the acidity of dark malts.

Sticking with these two examples, if we add a weak acid such as lactic acid to the Pilsner mash, we can lower the pH of that solution closer to 5.2–5.4. Likewise, if we add a weak base, such as sodium bicarbonate, to our stout mash, we can raise the pH to 5.4–5.6. How much acid or base we need to affect the pH depends on the makeup of the grist since malt will act as a buffer and resist the change. If the water is high in dissolved minerals, especially carbonate and bicarbonate, these will also serve as a buffer.

Buffers in the Water and Mash

Back to our foggy high school chemistry class, recall that buffers in a solution act to resist pH change. When adding an acid or a base to the mash, the pH first appears not to change. Envision the mash represented as an empty glass, and the water added to it represents the pH. The glass can only hold so much water. Drop by drop, you add water until it reaches a point where it overflows. You can think of the mash working the same way: You add acid or base milligram by milligram, and very little change happens until suddenly the buffers in the mash can’t resist anymore, and the pH changes drastically.

In the example of the stout or Pilsner grist, we used distilled water as a theoretical example. Real-world mashes use water with at least trace minerals since they improve enzymatic action and yeast health.

Distilled water has almost no buffering capacity, but dissolved solids in our water can act as buffers, specifically carbonate and bicarbonate. This means that when we add our Pilsner malt or our stout grist to our tap water, the pH will be affected by the buffering capacity of these dissolved solids, which will resist the pH change.

Consider the water that flows from your faucet: Tap water that has low mineral content has minimal buffering capacity, similar to, but not quite as extreme as, distilled water. In contrast, water high in minerals — especially carbonate and bicarbonates — will have more buffering capacity. Carbonate and bicarbonate are the big playmakers here and are the dissolved solids that mainly affect the water’s alkalinity. The alkalinity is responsible for most of the buffering capacity in our water, which directly affects the pH of the mash. Therefore, highly alkaline water has a very high buffering capacity and resists
pH change.

In contrast, low alkalinity water has much less buffering capacity, and the pH can be easily changed. What makes things interesting is that the alkalinity of your water will determine what color beer it is best suited to brew, meaning where the pH will fall into range without (or with minimal) mineral or acid additions. This information can be found in your water report.

Water Report and Alkalinity

There’s lots of information to unpack in a typical water report, but only a few items are helpful for brewing. The information also isn’t necessarily standardized in the way it is presented and might read differently depending on your municipality. But every report should list an approximation of the following:

Calcium (Ca²⁺)
Magnesium (Mg²⁺)
Sulfate (SO₄^2-)
Sodium (Na⁺)
Chloride (Cl^–)
Bicarbonate (HCO^3-)
Alkalinity, or Alkalinity as HCO^3-
Hardness, or Hardness as HCO^3-

Calcium, magnesium, sulfate, sodium, and chloride all have some effect on the final beer’s flavor and, to a lesser degree, the mash pH (we will get to these in a moment). But it’s the bicarbonate (HCO^3-) that has the most impact on the mash alkalinity and, therefore, the mash’s buffering power. So much so that if your water report doesn’t have a value for “bicarbonate/HCO^3-,” you can substitute the value given as “alkalinity” or “alkalinity as CaCO₃” since the majority of alkalinity will usually be bicarbonate.

The alkalinity of your water will determine what color of beer your water is best suited to brew. Water between 0–50 ppm (mg/L) levels is ideal for extremely pale beer. For pale to amber beers, 50–150 ppm (mg/L), and for dark beers, 150–300 ppm (mg/L). Higher alkalinity will help to neutralize darker and more acidic malts and target the mash into the proper enzymatic pH range.

“Hardness” or “hardness as HCO^3-” refers to water’s calcium and magnesium concentration. While “alkalinity as HCO^3-” and “hardness as HCO^3-” are not the same, they are somewhat linked. For example, boiling water high in “hardness” can cause some of the bicarbonate and/or carbonate to bind with the calcium and/or magnesium, precipitating some of it out as calcium carbonate and lowering the water’s hardness and alkalinity. This is known as temporary hardness. It was once a standard method to soften brewing water while reducing its alkalinity (the layer of calcium carbonate will be seen on the bottom of the kettle after the boil and time to settle). However, homebrewers will probably find it easier and less energy-intensive to dilute their water with distilled or reverse osmosis (RO) water instead of boiling to reduce hardness and alkalinity. It’s also more accurate.

For instance, if the alkalinity of your water is 100 and you split it 50/50 with distilled water, the alkalinity will be at 50 ppm — within the range of pale beer so that only a tiny amount of acid will be needed (if any) to hit your pH. You can use whatever ratio of distilled or RO water you like to get your alkalinity to your desired ppm, but remember, if you use all or close to all distilled or RO water, you need to add some minerals back in — most likely calcium, at the very least, for yeast health.

Checking the Mash pH

As stated, as long as it is between the “normal range” of about 6.5–8.5 pH, the pH of your water is of little concern. What matters is the pH of the mash.

The best way to check the pH of the mash is with a pH meter that has been properly calibrated between 4.01 pH and 7.01 pH using calibration solutions. Every pH meter brand is different, and the calibration and usage instructions must be followed. The pH meter should be calibrated before every brewing session.

When checking the mash or wort pH, it’s best to cool the sample to room temperature for an accurate reading. A correction must be made if the sample is too hot or too cold. A pH reading at mash temperature will be off by about +0.2 points. A sample at refrigeration temperature will be off by about -0.01.

Disposable pH strips are better than nothing, but their accuracy may be suspect, and the reading challenging to determine. Be sure to use pH papers within the 4.01 pH and 7.01 pH range.

Lowering the pH in the Mash

Remember: The alkalinity of the water acts as a buffer to the mash, and the mash acts as a buffer to anything we add to adjust its pH. Also, recall that for a pale beer, the ideal alkalinity of our water is under 50 ppm. 

Water alkalinity under 50 ppm doesn’t mean that adjustments won’t be needed on pale beers to bring the pH between 5.2–5.4. It just means that smaller adjustments will be required. Likewise, just because the alkalinity of water is over 50 ppm doesn’t mean you can’t brew pale beers. While dilution with distilled or RO is preferred, it isn’t always possible. Many brewers with high alkalinity use acids, acidulated malts, etc., to lower the pH of their mash to the desired range. The higher the alkalinity of the water, the more acid or acidulated malt, etc., will be needed. The problem is that the more acid added, the more potential it has to change the beer’s flavor.

Because each mash and water source is different, it is difficult to calculate how much acid will be needed for any given mash to make adjustments. Based on input, the brewing water software can estimate how much acid is required to adjust the mash to your desired pH. If you don’t have access to software, then the best way to adjust the pH in your mash is to add the acid a drop or two at a time, stir well, and check to see if it has made a difference. Obviously, the smaller the mash, the smaller the amount added. Likewise, the higher the alkalinity of the water, the more acid is required. Once the capacity of the buffering power is reached, pH change happens rapidly.

Lactic acid

Is a common food-grade acid used to adjust the pH in the mash since the flavors it provides are pleasant when under a certain threshold. But, if too much is used, it can create a sour “twang” that can detract from the beer.

Phosphoric acid

Is another common food-grade acid used to adjust the mash pH. In beer, it is almost flavorless. Malt naturally releases phosphates during the mash, which resembles phosphoric acid’s flavor.

Acidulated (or acid) malt

The Reinheitsgebot (German Law of Beer Purity) doesn’t allow any acid additions to be introduced when brewing, so the Germans found a clever way around this: Acidify the malt with a mild lactic acid fermentation.

Every 1% acidulated malt (by weight) of the total grain bill reduces the mash pH by 0.1 points. If your water is high in alkalinity, you can use up to 10% acid malt in the total grain bill without off-flavors.

Sauergut

German brewers have also skirted the Reinheitsgebot by souring a small portion of wort, called sauergut, and adding it to the mash to lower the pH. Sauergut can be made by adding a pure pitch of Lactobacillus or a small amount of barley malt (already naturally crawling with Lactobacillus) to the sample portion. The wort will then acidify and sour, as quick as in just few hours when kept about 108–112 °F (42–44 °C). A common practice is making the sauergut 12–24 hours before brewing, letting the sauergut sour to around pH 3.5 or under, and then portioning it off into the main mash to adjust the pH as necessary. Many brewers find adding sauergut to their mash is an easy way to adjust the pH and put a unique flavor print on their beer.

Minerals to lower pH

Calcium chloride (CaCl₂) and Calcium sulfate, aka gypsum (CaSO₄), can also lower the mash pH, but since they are flavoring salts, their flavor needs to be taken into consideration first. The amount of CaCl₂ or CaSO₄ needed to make pH changes may put them out of the acceptable flavor range unless using water with extremely low alkalinity. Their usage will be discussed later.

Raising the pH in the Mash

The pH of the mash should only need to be raised when brewing amber or dark beers. For stouts or porters, high alkalinity is necessary to land in the 5.4-5.6 zone. If the water source is already high in alkalinity, only minor adjustments will be needed (if any). Sodium bicarbonate (NaHCO₃) and calcium carbonate (CaCO₃) are the most common minerals to raise the alkalinity. 

Calcium carbonate (CaCO₃)

Is largely flavorless and does a great job raising alkalinity in nature due to time and dissolved CO₂ from the atmosphere. In the brewery, calcium carbonate will not dissolve well in tap water. More of it will dissolve in the mash due to the lower pH, but much of it will precipitate out. It will raise your calcium and may increase your alkalinity, but it is difficult to say how much. Because it is unpredictable, it’s not the best method of raising alkalinity. Since calcium is soluble, 1 gram of calcium carbonate per gallon (4 L) should raise calcium by about 50–55 ppm (mg/L). Since the carbonate is less soluble, 1 gram per gallon (4 L) may increase your CaCO₃ by as much as 160 ppm (mg/L), or it could be much less, depending on how much gets dissolved.

Sodium bicarbonate (NaHCO₃)

Or baking soda, will dissolve well in both brewing water and the mash and does a consistent job of raising the alkalinity and the pH of the mash. The problem is that it must be added judiciously since it will increase the sodium and affect the beer’s overall flavor. The flavor threshold of sodium varies from person to person, but a good rule is to keep the sodium (Na⁺) under 100 ppm (mg/L) lest the beer taste “salty.” One gram per gallon (4 L) of sodium bicarbonate in distilled water will raise the carbonate to about 190 ppm (mg/L) and the sodium to about 75 ppm (mg/L). For dosage, a good rule is not to go over 1.25 grams per gallon (4 L) to avoid issues with excessive sodium. If more alkalinity is desired, but the sodium is hitting the threshold, the brewer should try blending in some calcium carbonate.

Minerals for Beer Flavor 

The other minerals on the water report don’t do as much to affect the mash pH, but they do play a nuanced, though vital, role in beer flavor. As an analogy, let’s use table salt: When cooking, the right amount of salt makes the dish “pop.” Not enough, and the flavor is bland and boring. Too much, and the meal is inedible. Using minerals in brewing can have similar consequences.

Calcium sulfate (gypsum)

Gypsum profoundly affects beer’s “dryness” and can accentuate hop bitterness and, to some extent, hop aroma. It is historically the most popular flavoring salt used in brewing.

One gram of gypsum per gallon (4 L) of water will add about 60–62 ppm (mg/L) of calcium and 145–147 ppm (mg/L) of sulfate. It’s best to stay below 350 ppm (mg/L) of sulfate. While many brewers add gypsum indiscriminately to their mash (and even wort), remember that it is not a magical flavoring salt and can be overdone, creating harsh and unpleasant flavors. 

Calcium chloride (CaCI₂)

Calcium chloride emphasizes malt character while softening hop flavor or bitterness. It is nearly flavorless but will “sweeten” and “round” malt flavors when used at low levels. Calcium chloride is a valuable tool to raise water’s calcium to acceptable levels without raising sulfate.

One gram of calcium chloride per gallon (4 L) of water will raise the calcium to about 70–72 ppm (mg/L), while raising the chloride level to about 125–127 ppm (mg/L). It is best to keep the chloride level under 250 ppm (mgLl) for most beers, as too much chloride can make a beer taste salty or chemically.

Epsom salt (MgSO₄)

Epsom salt is used to raise magnesium (Mg) or to raise sulfate (SO₄) without raising calcium. It is commonly employed to recreate the classic Burton-on-Trent water profile for British-style ales (along with gypsum). However, Epsom salt must be used sparingly because magnesium can have a laxative effect — which could create quite a surprise at an inopportune time for the unsuspecting drinker.

One gram of Epsom salt per gallon (4 L) of water will raise the sulfate to about 101–103 ppm (mg/L) and the magnesium to about 24–26 ppm (mg/L). It’s best to keep the magnesium under about 35 ppm (mg/L).

Salt (sodium chloride, NaCI)

Non-iodized table salt affects flavor and can make the beer taste more “full” and “round.” If your beer tastes “thin,” adding a little salt may fill out the flavors and make for a more tasty beer. Be sure to use only non-iodized salt since iodine can affect yeast health. 

Salt will raise the sodium levels as well as the chloride levels in brewing. One gram of salt per gallon (4 L) of water will increase the sodium (Na⁺) by about 102-104 ppm (mg/L) and the chloride (CI) by about 158–160 ppm (mg/L). While people’s flavor threshold to salt will vary, keeping sodium under 100 ppm (mg/L) is best. Avoid salt when using sodium bicarbonate since it can quickly raise sodium to unacceptable levels.

Sodium bicarbonate and calcium bicarbonate

Neither of these salts should be used as flavoring salts. However, they can affect flavor when combined with other salts: Calcium bicarbonate raises sodium, and both salts raise calcium. Watch your sodium and calcium levels when using these salts in conjunction with others.

Sulfate-to-chloride ratio

The sulfate-to-chloride ratio should be considered for any beer style, especially hop-forward beers. For example, hazy pale ales typically use a 1:2 sulfate-to-chloride ratio to emphasize the “softness” of these beers. On the other hand, a West Coast IPA may use a 2:1 sulfate-to-chloride ratio to accentuate dryness and hop bitterness.

You can use whatever sulfate-to-chloride ratio you like (1:3, 1:1, 4:1, 0:1, 1:0, etc.); it’s up to the brewer to experiment with these ratios to see what works best for their beers and their tastes.

Calcium Levels in the Mash

As alluded to, calcium is an essential mineral in beer, but not necessarily for flavor. Calcium in the mash positively affects the enzymes and improves enzymatic function while acting as a yeast nutrient.

Calcium also reacts to oxalic acid, a troublesome organic acid released during mashing. Calcium binds with oxalic acid to form calcium oxalate, aka beer stone, which will precipitate out of the mash. It’s important to handle it in the mash so it doesn’t form in fermenters or packaging. Beer stone forms a brownish deposit that can harbor bacteria, create nucleation points where CO₂ collects, and cause excessive foaming and gushing. It is tough to remove without harsh acids.

To avoid problems with beer stone and provide yeast health and speedy mash conversion, be sure every mash has at least 50 ppm (mg/L) of calcium (calcium sulfate, calcium chloride, or calcium carbonate).

Water Chemistry Software

If you have your local water report, it’s easy to input those numbers into water and mash chemistry software to see how your water alkalinity affects the pH of your beer recipe. It also makes it easy to decide on RO or distilled water dilution ratios or mineral additions. Some can estimate how much acid or minerals are needed to bring your pH into the desired range. Some of the software is free online, while others are spreadsheets that can be downloaded for a small fee. Many recipe software programs and apps also include water chemistry software in their package. 

This is an edited excerpt from Keith T. Yager’s Unlocking Homebrew: The Four Keys to Tasty Beer (self-published, 2024).

Q: I have been an all-grain homebrewer for almost 15 years now. I typically start with reverse osmosis (RO) water and add Ca+2, Mg+2, Na+, HCO3- and Cl- as needed, depending on the beer that I am brewing. I measure mash pH and am normally within the recommended range of 5.2 to 5.5. What I would like help with is a formula for calculating/estimating mash pH so that I can make appropriate pre-mash acid/base adjustments vs. trying to catch up after the fact. I have used the Braukaiser spreadsheet but would like to see a summary of the actual formulas and supporting data used/needed to make reasonable pre-mash pH estimates. I am an engineer by training, so I’ll gladly labor through the math. 
— Dennis Sopcich • Loves Park, Illinois

A: Being able to predict mash pH based on brewing water composition and grist bill is something of great practical use to brewers. Clearly not all beer styles brewed in Munich, for example, are a good fit with the alkaline water in Munich without some adjustments and having some way to guide these tweaks before a brew is the general aim of many water calculations. The fact is that all such calculations are approximate because there are simply too many variables that affect mash pH, including water, malt, mash profile, boiling duration for decoction mashing, and mash thickness. I have spent a fair amount of time digging into your question and can provide some answers, so read on!

The most recent version of Kai Troester’s water calculator I could find on the Braukaiser website is version V1.58 dated September 16, 2012. The bad news is that this spreadsheet is password protected and the formulas are hidden. That’s probably why you submitted this question. The good news is that I am persistent with Excel and was able to find a tool to remove the password! Sorry Kai, but I had to pick your lock.

Let’s start with a summary of how Kai’s water spreadsheet is written. This tool is based on the work of Paul Kolbach that was first published in 1951. The translated title of his work is “The Influence of Brewing Water on the pH of Wort and Beer.” A.J. Delange translated pieces of this work collected by John Palmer and some of the German text was cleaned up by Kai Troester for translation. The translated document is not dated, but can be found at www.themodernbrewhouse.com/wp-content/uploads/2016/11/DeLange-1953-Kolbach-Translation.pdf. Kolbach developed the brewing concept of residual alkalinity (RA), expressed in terms of equivalents of calcium oxide, and came up with an easy-to-use factor equating +/- 10 units of RA to +/- 0.3 pH units. Let’s assume we produce wort using distilled water for mashing and sparging and our post-boil wort has a pH of 5.6. If we repeat the same brew with water with RA = +10, the predicted post-boil wort pH is 5.9. The same logic can be applied to mash pH estimation.

In Troester’s tool, he begins by calculating RA and applies a correction factor for mash thickness to account for the differences between predicted wort pH and mash pH (see www.byo.com/mr-wizard/using-softened-water/ for a review of how to calculate RA). Troester references his excellent white paper titled “The Effect of Brewing Water and Grist Composition on the pH of the Mash” published on his Braukaiser website where he provides extensive data related to the general topic, including specifics about mash thickness, mash pH, and how these relate to Kolbach’s wort pH rule. The takeaway here is that RA = +/- 10 °dH (degrees of German hardness) equates to a +/- 0.2 mash pH change when mash thickness is 4 parts water to 1 part malt (wt/wt). That’s a bit on thin side for most homebrewing (3:1 is more common), but as the data in Table 1 shows, mash thickness only has a minor effect on predicted mash pH.

Troester’s tool also calculates the predicted pH of mash using distilled water where RA = 0. This is where things become a little odd. Because distilled water has no RA, mash thickness does not affect predicted mash pH and the value that is returned is based solely on color and a big assumption about all pale malts. When color is set to 2 SRM, the predicted pH of mash produced from distilled water is 5.57. Not only does the pH of mashes made from different pale malts vary quite a bit, but it’s usually higher than 5.57. Most North American pale malts these days have a reported pH based on ASBC (American Society of Brewing Chemists) congress mashing of around 5.9. The easy way to use this information is to increase his estimates based on known values obtained from current malt analyses. You can see from the data in Table 1 that the predicted pH changes based on wort color and mash thickness are linear over the range shown, so the adjustment can also be linear.

Troester’s 2009 white paper takes a deep and very interesting dive into the topic of color, but incorporating the results of his mash trials into a single calculation is not simple because pale malts, crystal malts, high-kilned, and roasted malts all affect mash pH differently. In his Braukaiser calculator, he uses a single term combining beer color, % roasted malt, and % non-roasted malt as the way to bring specialty malts into his prediction of mash pH. Note that on a beer color basis, non-roasted malts, assumed to be crystal malts used in his pH shift calculation, are more acidic than roasted malt. This term is calculated by the following:

pH Shift from Color = (-) {(Beer Color in SRM) x [(0.21 x % non-roasted malt) + (0.06 x % roasted malt)]}/12 °Plato.

Although the Braukaiser pH shift from color term appears to be based on solid data, it seems to overestimate the effect of malt color on mash pH. Table 2 shows predicted mash pH at a single mash thickness using alkaline water (RA = 10 °dH) over a range of colors and their corresponding roasted malt component. Troester’s plots of mash pH versus beer color in his white paper don’t fall below about 5.1 when color is derived from roasted malt, yet the predicted mash pH from the combination of 10% roasted malt and 90 SRM is 4.35.

What does this all mean? In my opinion as someone who has written lots of spreadsheets, any review of a spreadsheet is likely to find some oddities. I noted a few because you asked how this tool is written. It’s also my opinion that Kai Troester developed a user-friendly, predictive tool to help navigate the deep topic of water chemistry. If I were to edit this tool, I would “unbury” the pH from base malt and make that an editable variable. I would also spend more time looking at the pH shift from color because it doesn’t pass the sniff test; other references coupled with my own brewing experience are not aligned with that metric.

It’s weird; every time I remove a liter from the brewing water well, it has more water when I return! This review is a good reminder that these types of tools are predictive and are never perfect. Users must be prepared to take notes and adjust their subsequent brews based on the results of the present. That’s my view on the meaning of this exploration.

And back to you, Dennis. Engineers like to understand their tools. Your question sent me on a fun quest that included watching numerous YouTube videos on how to unprotect Excel sheets when you don’t have the password, reading multiple articles about water, and digging into a complex spreadsheet. If you want to learn more, start with figuring out how to sneak past the lock!

Water is a critical brewing ingredient and yet is one of the least understood. John Palmer, who wrote the definitive book on the subject, Water: A Comprehensive Guide for Brewers, will take the mystery out of your approach to handling water in your brewery. You’ll learn not only the chemistry but also the tests you should be taking and the adjustments to make better beer.

You can download PDFs of the presentation slides at: https://byo.com/wp-content/uploads/Water-Bootcamp2023.pdf

Build a 0-ppm water filtration system

If you’ve worried about your water chemistry like I have, then you know how tricky it can be to get minerally consistent brewing water from any municipal supply. One possible upside to being on a municipal system is that some provide a mineral content report, which you can enter into your brewing software. But not all water departments provide that information and I don’t really trust the numbers I do get. You can buy water, but that is cumbersome and the cost adds up. You can send a sample of your tap or bottled brewing water to a lab to know the mineral content for 100% certainty. But this is an added cost and it’s only as reliable as your last sample and some municipal supplies change from month to month. Now I know brewing water doesn’t have to be perfect, but I’m tired of knowing little of the brewing water sourced from my municipal water supply.

We’ve had a reverse osmosis (RO) unit under our kitchen sink for years that’s produced great water but, due to leaking issues, was finally retired from that role. So, instantly my “brew-brain” kicked into thinking about how I could use this recently retired unit in my homebrewery . . . and not so much about how my family is going to get non-chalky ice cubes from the fridge in the foreseeable future. Don’t judge . . .you probably have a few of your own scores to boast about.

In researching what I needed for my brewing water filter (and yes, something for the family icemaker eventually) I learned about deionized (DI) or demineralized water and how scientists, aquarium owners, and car washes use it to filter their water. I also learned that during the RO membrane lifespan it removes ~99.9–85% of the solids from source water before replacement. My older RO membrane(s) showed 77 ppm (an 81.6% reduction in total dissolved solids or TDS), so they needed to be replaced. DI filter lifespans rely on receiving the cleanest water you can achieve prior to the deionization process.

There are a ton of choices out there, and you can get everything you need all in one setup if you’re buying new. “Reef”-type setups piqued my interest, as they were RO units with DI and carbon-block post filters. Since I already had the RO part of the unit I ordered a spot-free car rinse system to combine with it.

This unit consisted of two standard filter housings connected to each other and attached to a bracket, with 10-in. (25-cm) mixed-bed DI filter cartridges included. You can choose single-bed cartridges for each housing, which I’m doing next time to help minimize cost and maximize efficiency. If either filter’s plastic resin beads exhaust before the other, you don’t waste unused resin like with my mixed-bed resin. Some resin changes color as its filtering ability diminishes, making it easy to know when the resin needs to be replaced.

Now that I had everything, it was time to Frank-n-Filter this thing.

Tools and Materials

• TDS meter
• Plumber’s tape
• Filter housing wrench
• New or used RO unit (typically 3–5 stage filtration) with mounting bracket and flow control
• Permeate pump (mine came with my RO unit because 60 PSI is needed for a membrane to function effectively)
• Optional 2nd “matching RO membrane” (all membranes used have to match the flow control)
• Dual-deionizing filter housings with mounting bracket
• (2) 10-in. (25-cm) refillable resin filter cartridges and the resin you plan on using (mine came with full, refillable mixed-bed media cartridges)
• Necessary plumbing connections

Steps

1. Assemble the Pieces

Buy a total dissolved solids (TDS) meter before anything else and test the water you will be using. They aren’t very expensive (mine was $20 USD) and it helps knowing when to change filters and membranes. Now we can assess the situation and disassemble all the things that don’t work for your version or are broken, as was my case. I had a couple of older filter housings that wouldn’t fit to replace my RO unit’s broken housing and another RO membrane and its housing my parents gave me when theirs was replaced. I wanted to incorporate them into my build, as they were just gathering dust and would give my system its second RO membrane. More on that in a bit.

2. Lay out the Pieces

Figure out what’s going where so you can see any other products, tubing, or fittings you will need to make a project list. Determine your fittings/additional filters based on your project because yours will be different. I did all of this and then I ordered everything off my list from the internet. It took me three tries, so hopefully you plan better than me. I wish I had known the different size housing fittings (every housing I have is different), so I’ll be nice enough to list what I found to save you some headaches. You will find my RO unit with the to-tank fittings, filter housings, and housing bracket removed in the following photo. It’s attached now to the top of the Spot-Free Rinse DI filters. My old RO unit will be the secondary because of how things are already plumbed. I’ll add the other bracket, filter housings, and RO in a bit.

3. Filter Arrangement

Pre-filters are very important to preserving the longevity of your more expensive RO membranes, so they really are required and need replacement when due. I’m going to keep a log book of gallons made with my system. The photo below shows the two spare housings I added because my RO unit lost its sediment filter housing to the leak to end all leaks and my RO system’s retirement. Both the sediment and carbon block will filter down to 5 micron, thus protecting my RO membrane(s) from any larger particulate matter.

4. The Build

It’s frank-n-time! Now all the fixture brace parts need to come together so I can carry my filter unit. I also went ahead and attached everything I could with what I had from order number two. That little black bolt (A) is 1 of 3 spaced out evenly to distribute the weight and connect the two unit brace brackets for support. Since the filter housings are different heights, I drilled and matched the holes to the other side so they were equal when assembled. Drill one side, line them up back to back with all filter housing installed and mark the holes, then drill your marked holes. Bolt them together and you have a single unit now.

5. Gaining Efficiency

Photo 5 shows the series-double RO membrane is finally connected to the pre-filters and DI post-filters. Why the double RO you might ask? Well, in my research I came across some information about the waste-to-production ratio of RO, which we all know is bad. This helps to lessen my wasted water and almost double my RO output to my DI filters. Let me explain . . . I use wastewater staging to get a ratio of 1.5-gallons (5.7-L) brine (wastewater) to 1 gallon (3.8 L) of permeate (the good, filtered water). This, as a single unit, would get around 2.8-to-1. If running parallel it would actually be worse at 3.125-to-1.

DIY or buying new, you need to determine how much pre-filtration and TDS you want removed to prolong your DI filter lifespan, because DI resin is the magic that gets us basically to zero TDS. My unit’s filtering path starts with the supply water going into the pre-filters. It then flows to the white filters (old carbon-block RO filters) and the first RO membrane, where the permeate mixes at the y-connection with the second RO’s permeate. Now, into the permeate-in side of the black pump. This happens simultaneously, while the brine from RO one feeds the supply of the second RO membrane. The brine from the second passes through the flow restriction and then connects to the brine-in side of the pump. The brine then exits as a single unit would, to your drain. The pump outputs the good water through one last carbon filter on its way (blue tubing) to the clear DI filter housings before exiting as near-zero TDS water (green tubing).

6. Test Run

I pulled out my TDS meter and hooked up the Frank-n-Filter to the old fittings under my sink for testing. The supply out of the tap came in at 420 ppm, post-dual ROs was 77 ppm, and post-DI was 0 ppm at close to 1.8 gallons (6.8 L) per minute of output. The DI unit I bought said it was good for about 30 gallons (113 L) of “normal” hardness tap water at 0.75 GPM/2.8 LPM (it had a restrictor fitting that I removed). Running RO through it makes it last a lot longer and the pulse action of the RO pump allows a period of time for water to react, sitting still with the beads. In the near future I’m going to replace my RO membranes, move to individual ion resin housings (one cation, one anion) and buy matching pre-filter housings, but overall I am very happy! After testing I rigged up a keg tap to fill my Sanke kegs for brew day.

Q: I recently was told by another brewer I should not be adding magnesium to my brew water because of its laxative effects. Is this true? I’ve never heard of this being an issue. Also, how much magnesium does a person need to consume for that effect to kick in?
— Anonymous professional brewer • via email

A: According to the article “Can You Take Too Much Magnesium” published on the Medical News Today website, the National Institutes of Health recommends 310–320 mg as the daily magnesium allowance for adult women and 400–420 mg as the daily magnesium allowance for adult men. Although typical diets may naturally contain sufficient magnesium to satisfy daily recommendations, some people take dietary supplements for a variety of reasons including magnesium deficiencies associated with the modern diet.

The NIH recommendation for all people older than 9 is to limit magnesium supplements to 350 mg per day (this is above magnesium ingested from food and beverages). I don’t offer medical advice because I am a brewer, so please read up on magnesium if you want to know more about how it’s used by the body and why there is a recommended daily allowance.

It is well known that magnesium has a laxative effect on people when ionic magnesium, for example from salts like magnesium chloride and magnesium sulfate, is ingested above about 350 mg/day. And higher consumption rates above 350 mg/day usually leads to diarrhea. That’s why my friend does not want to add magnesium to brewing water. The related questions are: 1) how much magnesium is normally present in beer and 2) how much magnesium needs to be added to water to affect beer flavor?

Commercially brewed beers typically contain between about 40–150 ppm (mg/L) of magnesium. It’s hard to know how much of this magnesium is from the brewing water, but levels in water are typically below 40 ppm, meaning that the balance originates from other brewing ingredients, primarily malt. That’s a good thing because yeast do require magnesium for certain enzymatic reactions, and water devoid of magnesium need not be a concern.

The easiest way to understand how magnesium influences beer flavor is to buy Epsom salt without any aromatherapy additives.

The reason I am a fan of magnesium in brewing water is that it adds to the flavor of beer. At low levels, magnesium is hard to pick up, but is known to make water more refreshing. That may be why Dasani water adds a magnesium salt to its water. But when the concentration in water is increased to 20–40 ppm, magnesium adds a distinctive bitter-metallic flavor that can be detected in the finished beer. Why do all beers not taste like magnesium given the concentration in malt? It’s likely the form; magnesium in malt is largely bound or associated with proteins, nucleic acids, and bran. Plant physiology aside, magnesium added to brewing water affects beer flavor.

The easiest way to understand how magnesium influences beer flavor is to buy Epsom salt (magnesium sulfate heptahydrate) without any aromatherapy additives. Make up a solution in water and add a few drops to a beer for tasting. If you like what a bit of magnesium adds to your pint of beer, this salt may be a water treatment you should try in your next brew.

Back to the original concern, how much magnesium-spiked beer can the average beer lover consume without having gastric issues? Referencing the NIH recommendations, the maximum intake from supplements is 350 mg/L. If we consider magnesium added to brewing water as a supplement and set our level in brewing water at 35 mg/L, which is on the high side, a beer drinker would hit this maximum intake after consuming 10 liters, or (28) 12-ounce bottles of beer.

Like I stated earlier, I don’t provide medical advice. But I will wager a guess that most people will have problems much worse than a touch of the runs after consuming 28 beers in a day. Therefore, I suggest that adding a touch of magnesium to brewing water is not likely to cause gastrointestinal problems for the typical beer lover, even if your nickname is Joe Six-Pack. That’s my answer and I am sticking to it!

Most brewers know that beer is comprised of somewhere between 90–95% water. So it makes sense that the water you are using can have a major impact on the beer. In the best case, the water profile can enhance and lift the beer and its body and mouthfeel. In the worst case, it can leave the brewer with a beer tasting similar to chewing on a Band-Aid and smelling like hot plastic. Water treatments don’t need to be complicated, especially if you can start with reverse osmosis (RO) water. But even without RO, some easy tricks should produce a fine beer. 

Tap vs. Reverse Osmosis

On my first trip to Florida, I poured a cup of tap water when I arrived at the condo we were staying . . . only to quickly spit it out. To me it was undrinkable . . . it was like drinking a sulfur stew. If that at all describes your water, then RO water is highly recommended. Also, if you’re in a location that deals with very hard water, high iron, or other total dissolved solids, then RO water would also be recommended. Why? Because what the reverse osmosis process does is strip the water of the dissolved solids that can possibly wreck havoc on your beer. If purchasing an RO system is out of your reach currently, purchasing 5-gallon (19-L) jugs of water at your grocery store is another option.

For folks that are on a municipal water supply, tap water may present itself as nearly undrinkable due to the chlorination process many water departments add to the supply. But chlorines are one of the easiest compounds to treat when it comes to brewing. Campden tablets (sodium metabisulfite) are what I consider the easiest way to treat both chlorine and chloramines found in your water supply. One crushed tablet added to your brewing water will treat up to 20 gallons (76 L). Half a tablet is good for a 5-gallon (19-L) batch size. Adding a little too much is not a bad thing. I used to treat the water the night before brew day but I have since learned that is unnecessary as the metabisulfite acts quickly. Adding while the strike water is warming up is all that is needed.

Carbon block filtration is another way to treat chlorinated municipal water. This is a little more costly and filters need to be replaced regularly. Also, carbon block filters do need time to properly treat the chloramines so a slow fill is recommended when using this type of setup. 

For brewers using tap water, obtaining a water report from municipal town/city water departments is recommended for those that have them available. You may need to send water samples away to an agricultural or other water analysis laboratory if they aren’t available or if you are using well water. Once you have a water report in hand, it gets easier to burrow down into the details of how to adjust your specific water.

Water Salts

Folks utilizing RO, or very soft water that is low in total dissolved solids, start with a leg up since it is the easiest water to work with in a brewery. It’s like trying to paint your masterpiece with a blank canvas versus one where Jackson Pollack had already applied a few strokes. First off, there is a big difference here between all-grain brewers and brewers utilizing extracts. Please note that extracts already have salts in them and generally I don’t add more unless it is truly desired.

There are several salts that we can utilize to affect the flavor of the beer, typically calcium chloride and calcium sulfate (gypsum) are the two most widely utilized. But there are others that can be utilized to provide balance or lift to the beer: Calcium carbonate, magnesium sulfate (Epsom), and sodium chloride (table salt) are most commonly used and easy to obtain. One of the best ways to get a sense of how they can impact beer is by experimenting on your own. Get some distilled or RO water and start sprinkling the salts and taste. See how each impacts the mouthfeel and taste of the water. Then try it again on beer, either a homebrew or commercially available one. Just be careful of foaming with carbonated beers when you sprinkle, as the salt will provide nucleation sites for the carbon dioxide to come out of solution.

How much salt to add is going to be tricky as it depends on your water profile and your desired goal with the beer. If using tap water, you will need to take the starting level of each dissolved ion from the various salts into account before making any additions. This is where the water report is essential.

Residual Alkalinity

This is a complex topic and for the sake of brevity, I will say that utilizing RO water will almost always be the best solution. If you are dealing with hard water, lactic or phosphoric acid may be your best friend. Whether working with tap water or RO, for  more in-depth coverage on this topic, I’ll refer to you to the following article: https://byo.com/article/understanding-residual-alkalinity-ph/

To wrap things up, I want to add that if you are using RO or very soft water low in dissolved solids, Gordon Strong did an excellent dive into the topic found in the March-April 2020 issue (or at https://byo.com/article/brewing-with-reverse-osmosis-water/). He covers several different beer styles and how to build up the mineral profile to match the style.

Q: In the January-February 2023 issue of BYO, you reference your water tool. Can you please shed some light on that?
— Frank Long • Cooperstown, New York

A: Me and my big fingers! Did I type some words about my water tool? While it’s tempting to geek out with water math, I’ll try to keep this answer informative without jumping down the drain. In my opinion, the first step in assessing brewing water is the calculation of residual alkalinity using Kolbach’s method from 1951. While it’s nice to understand the units behind the calculation, it’s not required. Residual alkalinity (RA) = (bicarbonate concentration [mg/L] x 0.046) – (calcium concentration [mg/L] x 0.04) – (magnesium concentration [mg/L] x 0.033). For the sake of discussion, assume we have a water report for our local water and know we have 76-ppm (same as mg/L) calcium, 18-ppm magnesium, and 295-ppm total alkalinity as CaCO₃.

We have everything we need to calculate RA, except we need to convert 295-ppm total alkalinity as CaCO₃ to ppm HCO₃^– by multiplying 295 by 1.22. RA = (295 x 1.22 x 0.046) – (76 x 0.04) – (18 x 0.033) = 12.9 °dH (that’s German degrees of hardness, another term that is nice to know about but not required to use the math). Because RA is positive, we know we have alkaline water that will increase mash pH over a standard mash test performed using distilled water. When RA is negative, mash pH is lower than the standard mash. The other thing RA gives us is a magnitude of change; (+) 10 °dH corresponds to an increase in mash pH of ~0.3 and (-) 10 °dH corresponds to a reduction in mash of ~0.3. Looks like our water is pretty darn alkaline and is predicted to drive our mash pH up by about 0.4 pH units! Now what? This is where my water tool helps provide solutions.

There are a few approaches to using this type of water: 1) brew a beer using acidic specialty malts (like roasted or caramel malts) to balance the alkalinity of the water; 2) add calcium and/or magnesium salts to reduce RA; 3) dilute RA with reverse osmosis (RO) water; 4) add an acidulant (usually lactic acid, phosphoric acid, or acid malt); and/or 5) remove alkalinity by boiling and/or treating with calcium hydroxide. These methods, except for the last, are all easy to use for brewers of a wide range of brew sizes, including us homebrewers. And as is the case with many a brewing solution, simultaneously using more than one method is totally cool.

So, that tool you’re asking about combines the approaches listed above, except for alkalinity removal, into an easy-to-use calculator ultimately designed to predict mash pH based on water RA, which we have just calculated, and grist bill. Although mash pH is the process variable most brewers focus on when adjusting brewing water, water components unrelated to pH are also a big deal because they affect beer flavor. John Palmer refers to these components as seasoning, which is really a great analogy. Chloride, sulfate, and sodium targets are entered along with targets for calcium, magnesium, and bicarbonate. The calculations predict mash pH based on the target water profile and grist bill, as well as providing a “water recipe” to use for the brew. When the target concentration of any ion is less than the concentration in the water being treated, RO dilution water volume is calculated.

In addition to knowing the RA of the untreated water, some grist bill basics are needed. This is where mash pH prediction becomes approximate. While the standard malt analytics used to prepare a certificate of analysis (COA) for base malts includes wort pH, special malt data do not. But we do have rules of thumb for how special ingredients like crystal, light-roasted, dark-roasted, and acidulated grains affect mash pH. For each percent of these grain types, pH is reduced by 0.025 (crystal), 0.002 (Munich), 0.03 (light-roasted), 0.05 (dark-roasted), and 0.1 (acidulated) pH units. For example, a mash made up of 95% Pilsner malt with a wort pH of 5.8 (this is from the malt COA), 5% crystal malt, and water with RA = 0 (same as distilled water used for lab testing), will have a mash pH of about 5.68 (5.8 – (5 x 0.025)). The source of this information is from Siebel Institute of Technology’s lectures about brewing water and residual alkalinity and provides the practical brewer with estimates.

In my opinion, the first step in assessing brewing water is the calculation of residual alkalinity using Kolbach’s method from 1951

Let’s assume we are brewing a beer with the water loosely defined above, do not want to add any brewing salts, liquid acids, or RO water, and want the mash pH to be about 5.5. To crunch the numbers, the only two things to consider are RA (12.9 °dH in our assumed water) and grist composition. The water RA tells us our mash pH is going to be pushed up about 0.4 pH units (12.9 °dH / 0.3 pH units per °dH = 0.43) from the lab wort pH (5.8 gets bumped to 6.2), so this brew will either require a big dose of specialty malts with color because light-colored special malts are not very acidic, or we can add acidulated malt to help bring the mash pH into balance. One solution that works out is using 40% base malt, 50% Munich malt, 5% light-roasted malt, and 5% acidulated malt. That grist bill could be a dunkel. Not a bad beer to brew using my example water that just happens to match a reference for Munich water.

But what about brewing a Pilsner with this same water? A great start to this problem is to reduce the very high RA. Calcium additions are an option, but the best water profiles for Pilsner beers have a neutral RA and are relatively low in total dissolved solids (TDS is the sum of all water ions). Adding more salts to the base would simply drive TDS up. The best solutions are either diluting with RO or removing alkalinity. Alkalinity removal is a literal science project and not simple without the requisite set-up, so I am not going to that well.

Diluting with RO water is simple, but target ion concentrations are first required for the calculation. In example 1 below, the calcium target was set to 50 ppm (down from 76) and the bicarbonate target was set to 100 ppm (down from 360). The water tool does the rest, providing base water and RO water volumes, along with required salt additions, options for acid additives, and the profile of the adjusted water. Note that there is still some residual alkalinity because I set the target bicarbonate level down to 100 ppm. The summary below includes a good dose of acid to bring the mash pH down to the target of 5.45.

Using the same water with 12.9 °dH, let’s pivot into IPA territory. Now, we want to know more about water than simply the ions driving pH because IPA water typically has much more “seasoning” than Pilsner water. Per Kunze, Munich well water (source not stated) contains little sulfate or chloride; 10 and 2 ppm respectively. Let’s assume our IPA is brewed using 90% pale ale malt with a lab wort pH of 5.7, 5% wheat malt for added foam stability, and 5% light crystal malt for color. This grist and water combination will yield a higher mash pH than our target of 5.4 because of the high RA.

As high TDS waters are common for classic ales and because our base water has very little sulfate or chloride, a good approach to this beer is to reduce RA by adding a combination of calcium sulfate, calcium chloride, and/or magnesium sulfate. The choice of salts depends on what we want in our profile. The water recipe below is one of many possibilities. The combination of grist bill and water salt additions gets us really close to our target mash pH, while providing a similar adjusted water profile to the mineral-rich waters used in classic ales. In example 2 found below, the predicted mash pH (not shown) is still a bit higher than the target and my water tool suggests the addition of a bit of acid to correct.

To download a copy of Mr. Wizard’s water calculator, click here.

Q: I recently bought a pH meter and got some calibration reagents with it. I’m just about finished with my first bottles so I was about to shop around for some new reagents when it hit me . . . do I really need to buy a 7.0 reagent? If I remember from high school chemistry class correctly (it’s been 40 years!), can’t I just use distilled water to calibrate for 7.0?
— Jeff Cutler • Redmond, Oregon

A: On paper, using distilled water as a pH 7.0 makes sense because the ionization constant is 1 x 10^-14 and the concentration of hydrogen ions is 1 x 10^-7 molar at 77 °F (25 °C). Converting this to pH by poking 1 x 10^-7 into the old calculator and hitting the log key results in -7, and multiplying this by -1 gives us 7; that should be the pH of pure water. I am impressed you remembered that from high school chemistry class. The problem is that water is rarely pure because it is the universal solvent and dissolves all sorts of things, including gases. And even if you were able to keep pure water pure in an environment without CO₂, the ionic strength of pure water is too weak for a pH probe to properly function. A pinch of salt could be used to solve that problem.

Although the concentration of carbon dioxide in the atmosphere is only 400 ppm, that’s plenty to affect the pH of water because carbon dioxide sets up a powerful buffer system in water. This same buffering system is present in blood. In the case of water, the carbonate buffer system raises pure water pH up to about 8.2. The takeaway is that you need to buy two buffers to calibrate your pH meter. When you go shopping for pH buffers, you will discover that there are several options, with the most common being pH 4.01, 7.00, and 10.01. Brewers should calibrate their meters using pH 4.01 and 7.00 buffers because brewing biochemistry occurs in the acidic world.

You might be wondering why these pH standards are not affected by carbon dioxide in the atmosphere like water. The answer is because they are buffers themselves. Just in case you were not paying attention during this chapter in chemistry class, buffers are solutions containing a conjugate acid-base pair that are able to resist, or buffer, pH changes. Buffering capacity is directly related to the concentration of these compounds and is limited by how much acid or base can be added before the pH changes. This is why buffers need to be periodically replaced and why they should be stored in closed containers that prevent evaporation. One final point: Don’t ever store your pH meter’s probe in distilled water!