Diabetes and Beer, Chitosan, & Home Pasteurization

Q. You mentioned that you use a GLP-1 drug. What has your experience been with beer consumption while taking it?
David Hernandez
Springfield, Missouri

A. I was diagnosed with Type 2 diabetes in the spring of 2023 during a routine check-up. For those of you not well-versed in this subject, here’s a brief overview. Type 2 — sometimes called adult-onset — diabetes is the form that emerges later in life. Unlike Type 1 diabetes, Type 2 treatment these days does not typically include insulin injections.

At first, I was a bit shocked because this wasn’t something I had spent much time thinking about. But soon enough, it was time to follow my doctor’s advice. I responded well to the two prescribed drugs, and my A1C level — a measure of hemoglobin-bound glucose and an indicator of average blood glucose concentration over the roughly three-month lifespan of a red blood cell — quickly fell into the normal range. I dodged a bullet and my eyes were opened to GLP-1 drugs, and soon I was able to get a prescription for Mounjaro.

Mounjaro, unlike other GLP-1 drugs on the market, is a combination of GLP-1 and GIP agonists. These compounds mimic hormones related to glucose metabolism, increasing insulin release after eating or drinking while often decreasing glucagon (which raises blood sugar), slowing digestion, and reducing cravings. One key to my journey through all of this has been my use of a continuous blood glucose monitor, or CGM. Although I could have stopped using one long ago because of my successful treatment, I continue to wear a CGM. They’re inexpensive when covered by insurance, and they provide incredible, continuous, real-time data.

I quickly discovered that I was my own walking test subject. Eat this, drink that, take a walk, sit on my tail — and check out the results! The first thing that became apparent was that consuming starchy foods like bread and rice caused a quick spike in blood glucose. Not a huge surprise, but it hits differently when you see the data streaming live on your phone. Interestingly, my spikes were reduced when I ate veggies and/or protein along with bread or rice. Another quick discovery: Walking after eating has a big effect on how long those spikes last. Even a relatively short walk is effective in reducing the intensity and duration of post-meal glucose spikes. Nothing too shocking so far — but what about beer and other alcoholic beverages?

Alcohol consumption was where things got surprising for this formerly ignorant guy with Type 2 diabetes. Alcohol often lowers blood glucose levels. Because I use a CGM, I quickly discovered that low-glucose alarms coincided with having a beer on an empty stomach. Interesting! I also found that certain types of beer were worse than eating a big chunk of bread or a small portion of rice. These included beers with high finishing gravities — often not obviously sweet — massive imperial stouts, and even some non-alcoholic (NA) beers. Seeing spikes after drinking NAs was a surprise and opened my eyes to different types of NAs in the market.

The last major realization was the powerful effect Mounjaro has on my appetite. At first, the effect wasn’t noticeable. The dosage of these drugs is slowly increased over several months because jumping straight to a high dose can cause nausea. Even low doses don’t sit well with some people, and not everyone can tolerate these drugs. Luckily for me, I’ve never had an issue. As my dosage was gradually increased, I discovered that overindulgence in almost anything resulted in an extreme sensation of fullness.

I know this is a major departure from my usual brewing discussions, but the sad truth is that my story is all too common these days. My experience may become yours one day. See that as a good thing, because my disease was spotted before it became a serious problem. You asked about my experience with beer consumption, and I’ve finally built up to the crux of your question.

Beer makes me feel full. In my world, that just sucks because beer is at the center of my profession. I still love it, but drinking something like a liter of festbier takes a bit of planning. And here we are — threading the needle of being on a wonder drug like Mounjaro, with all its benefits, while still wanting to drink beer like a rockstar.

Listen up, folks who are in the same boat: Start brewing beers with lower OGs, because those big, burly beasts we all know and love push all the wrong buttons in the “feeling way too full” department. Highly hopped beers — especially hazies — also fill me up. What doesn’t seem to make me feel full includes wine, dry beers (even those with big malty flavors), moderately hopped beers, and beers with balanced flavor profiles. That last one’s a bit of a shocker. In the past, I could muscle through unbalanced beers, but not these days. Lucky for me, most German-style, balanced IPAs, and nitro beers remain easy for me to enjoy without being bloated.

Q. I have read a few things about the use of chitosan in beer and would like to get your input on this topic.
Kevin Sullivan
Spokane, Washington

A. Until recently, I hadn’t paid much attention to chitosan because it was one of those finings that seemed more popular among winemakers than brewers. And the few chitosan products I knew about that were available commercially were made from shellfish, posing an allergen risk for consumers with shellfish allergies. That’s not to say other chitosan products haven’t been around for a long time — I was simply unaware of them.

Two things have recently opened my eyes to chitosan products: The search for alternatives to pasteurization for use in non-alcoholic beer and the growing market visibility of fungal (vegan) chitosan for use as a beer clarifier. Before digging into these applications, I want to briefly introduce chitosan to those who may not be familiar with it.

Chitosan is a naturally derived fining agent used to clarify beer (and wine) by helping unwanted haze-forming particles drop out of suspension. Although chitosan isn’t a protein, it behaves similarly to isinglass. It’s produced by deacetylating chitin, a structural polysaccharide found primarily in the shells of crustaceans like shrimp and crabs — but it can also be sourced from fungi. In fact, fungal cell walls, especially those of Aspergillus and Mucor — a genus of filamentous fungi found in soil, decaying organic matter, and even some fermented foods — provide an increasingly popular and sustainable non-animal source. 

Chemically, chitosan is a positively charged polymer and ranks as the second most abundant natural polysaccharide on Earth, right after cellulose. That abundance makes it both renewable and relatively inexpensive. When added to beer, chitosan’s positive charge acts like a magnet for negatively charged particles — proteins, yeast cells, tannins, and other haze formers. These bind together into heavier clumps that sink out of suspension, leaving the beer clear and bright. Chitosan works gently, without stripping flavor or aroma, and is often paired with silica-based finings for even better clarity and stability.

Although chitosan can effectively clarify beer on its own, it’s often paired with kieselsol — a colloidal silica better known by the trade name Biofine Clear. The name kieselsol comes from the German word for flint or silica — “Kiesel” — combined with “sol,” which refers to a specific type of colloidal solution. The two work synergistically because they carry opposite electrical charges: Chitosan is positively charged, while kieselsol is negatively charged. When used together, they act like a two-step magnetic system. Kieselsol first binds to haze-forming proteins and other positively charged particles, creating small flocculates. Chitosan is then added, binding to the remaining negatively charged yeast cells, tannins, and colloids. The result is a faster, more efficient precipitation of haze components than either agent can achieve alone. This pairing produces bright, shelf-stable beer without filtration — ideal for brewers who want professional clarity while maintaining full flavor integrity.

That’s the fining story about chitosan. A more recent development involves specific chitosan fractions being used for their antimicrobial properties. Chiber — short for Chitin-Based Extract for Beverages — is a new product gaining attention in the beverage and food industries for its ability to inhibit and prevent the growth of certain microorganisms.

Unlike heat pasteurization, Chiber is active immediately upon addition and continues to work through packaging, offering an advantage over flash pasteurization, where contamination during filling can lead to in-package spoilage. While larger breweries often use tunnel pasteurization to treat beer in the package, flash pasteurization — a lower-cost, inline process — is more common among craft brewers. However, the risk of contamination during canning, bottling, or kegging has many brewers exploring alternative methods to meet the growing demand for safe, shelf-stable, non-alcoholic and low-alcohol beers.

Chiber is already being tested by some brewers, but because it’s relatively new to the market, most are still trialing it and developing best practices. The feedback I’ve received from brewers who have used or are currently trialing Chiber is that more testing is needed. It may prove to be a great fit for simpler beverages like sodas but may or may not be the best option for beer.

And it’s not an off-the-shelf additive; testing is required to establish an appropriate process for each beverage type. A simple preliminary check involves confirming that Chiber does not cause sediment formation when added to the product. Because it’s a specific fraction of chitosan, Chiber can also act as a fining agent — so if the target beverage is unstable or prone to haze, the active antimicrobial ingredient may be reduced as it binds and settles out with other particles. Several brewers have told me that it simply doesn’t work with hazy beers because it causes clarification and is essentially neutralized in the process.

To our commercial readers who are interested in brewing non-alcoholics (NAs): Work with a process authority and conduct extensive third-party challenge testing to ensure your product is stable, regardless of the stabilization method used. And until we have more research data from multiple research groups, please don’t put NAs on draft.

Q. I am interested in experimenting with home pasteurization. Over the years, I’ve read that adding fruit to fermented beer, backsweetening cider, and now making no- and low-alcohol beer are all good candidates for pasteurization. Is there a way to pasteurize at home without embarking on some sort of crazy project?
Taylor Carter
Lille, France

A. Although Louis Pasteur is best remembered for milk pasteurization, his original method was developed for beer. And the cool thing about the process we now call pasteurization is that it’s pretty darn simple.

Until the advent of in-line heating and cooling, pasteurization was a batch process. In fact, batch pasteurization is still commonly used by small-scale producers to render products safe and shelf-stable. But the history of beer is more about how advancements in science and engineering allowed brewers to grow large. Pasteurization is at the heart of that history. Brewers were quick to take note of Pasteur’s Études sur la bière (Studies on Beer), and Carlsberg was the first brewery to pasteurize beer for commercial sale in the 1870s. 

As my mentor and professor to many Dr. Michael J. Lewis repeated in every lecture on packaging: Pasteurization allows a brewer to sleep at night. In practical terms, this is because worries about microbiological spoilage and unwanted secondary fermentation are simply erased. 

The good news is that you can easily pasteurize beer at home with just a few simple pieces of equipment. Depending on your setup, you may already have the basic tools. But before discussing how, let’s review the what. Pasteurization at home is performed using a batch method. In essence, this is just atmospheric canning: Prepare a hot water bath, load it with bottles of beer, and process at a set temperature for a set time. A typical pasteurization process used for the range you ask about is 50 Pasteurization Units (PU), where 1 PU = 1 minute at 60 °C (140 °F). The relationship between temperature and pasteurization rate is exponential, expressed as:

PU = t x 1.393^(T-60)

Where “T” is the product temperature in °C and “t” is time in minutes. Using this equation, it’s easy to see why just a few degrees make a big difference. For example, 1 minute at 65 °C (149 °F) equals about 5.2 PU, so 10 minutes at that temperature yields roughly 50 PU. The current recommendation for non-alcoholic beers is about 75 PU, or around 15 minutes at 65 °C (149 °F). The time and temperature together are known as the thermal process.

The main challenge with all types of pasteurization is starting the timer at the right moment. If your process is 15 minutes at 65 °C (149 °F), the timer doesn’t start until the coldest spot in the bottle reaches 65 °C (149 °F). Commercial producers use in-line probes and in-package sensors for this. Smaller producers often use a test bottle fitted with a thermometer to monitor the process. 

If you want to pasteurize at home, one key is to use far more water in your water bath than the mass of product added. This helps prevent a big temperature drop when you add your bottles or cans. A properly sized heater and water pump are also needed. In a nutshell, a large reservoir of water is heated to a temperature a couple of degrees higher than your target process temperature. Because bottled beer has a large thermal mass, you need a heater capable of making up the heat loss. That’s the engineering part of this answer that I’m choosing to skip — but for the curious, that means considering the heat transfer coefficient between glass and liquid, the specific heat of the product, and the total wattage required to maintain a uniform thermal field. Even a 1500-watt immersion heater, when coupled with a small circulation pump, can maintain a 20- to 25-liter bath with less than ±0.5 °C variation (5–7 gallon bath with less than 1 °F). Circulation eliminates stratification and ensures that every bottle follows a near-identical heating curve. For the more technically inclined, thermocouples or data loggers can be used to integrate the pasteurization curve and calculate total PU delivered. After the bottles are added, the process sensor is monitored, the timer started once the target temperature is reached, and the bottles removed after the timer has elapsed.

Over-pasteurization can result in cooked or oxidized beer. Cooking can be controlled by establishing the minimum process required to achieve your goals, and oxidation is minimized by reducing oxygen pickup during packaging. The key point is that the thermal process should be ended by cooling as soon as possible after pasteurization is complete.