The project began with a deceptively simple question: What is the oldest brewable yeast available to us today? That question set me on an 18-month journey that would combine history, archaeology, and brewing science in a way few projects ever have.

After researching multiple strains of yeast, I came across a German company called Primer’s Yeast (which, unfortunately, is no longer in business). The company had collaborated with researchers at Tel es-Safi, an ancient brewery site, where yeast cells dating to around the 9th century BCE were recovered from the interior surfaces of ceramic vessels once used for fermentation. Yeast can survive in a dormant state for astonishing lengths of time, especially when trapped in porous materials like clay. 

At Tel es-Safi, researchers carefully extracted microscopic samples from the inner walls of ancient brewing vessels. These samples were cultured under sterile conditions, and genetic sequencing confirmed that the organisms were indeed brewing yeasts rather than environmental contaminants. The site itself, identified as the Philistine city of Gath, has long been associated with large-scale beer production, and excavations indicate industrial-scale activity during the Iron Age. Household-level brewing is also attested in the region. For me, the idea that living cells could persist for nearly three millennia and then be coaxed back into activity was as compelling as the beer they would eventually produce.

I have both a B.A. and an M.A. in Middle East Studies and have spent years studying the culture and history of the Levant, a historical region in the Eastern Mediterranean, making the discovery irresistible. After many back-and-forth discussions with Primer’s Yeast, I was able to secure a sample of this ancient yeast — and an opportunity to brew a beer that someone living nearly 3,000 years ago might have recognized.

The idea of reviving ancient yeast was not entirely new. In 2019, Seamus Blackley, best known as the creator of the Xbox, made headlines when he worked with an Egyptologist and a microbiologist to extract dormant yeast from Old Kingdom Egyptian vessels. He used it to bake bread with ancient grains like emmer and barley. The bread, he said, was sweeter and richer than modern sourdough. His Twitter (now X) thread documenting the process went viral, sparking global fascination with the idea of tasting history. If bread could be reborn from antiquity, why not beer? That question lingered in the cultural imagination, and my project picked up the thread, shifting the focus from the oven to the fermenter. 

Of course, saying you are going to brew a 3,000-year-old beer is much like saying you are going to make ancient ice cream. There is no way to absolutely recreate the conditions, flavors, and ingredients of antiquity. The water, the mineral content, the starches, and the fermentables all differ from what they were millennia ago. Yet there are general attributes that remain recognizable across time. For beer, “recognizable” rests on three pillars: The grains and adjuncts available in the region, the equipment and heating methods that shaped flavor, and the fermentation practices that determined acidity and carbonation. 

In the Eastern Mediterranean of the late Bronze and early Iron Ages, open-vessel fermentations at ambient temperatures probably produced beers with low natural carbonation and a gentle acidity. The result was likely a beverage that, while not identical to modern beer, would still have been recognizable to ancient drinkers — lightly smoked, gently sour, floral, and only faintly carbonated.

The first step in recreating such a beer was to identify the correct ingredients. I began by combing through academic articles and primary sources, searching for evidence of what ancient brewers used. What I found was a great deal of conjecture. The base ingredients were clear enough — barley and, to a lesser extent, emmer wheat — but the adjuncts were far more uncertain. Many articles mentioned dates, figs, grapes, and other fruits, but the amounts varied wildly, and the resulting flavors could swing dramatically depending on the proportions. Fruit adjuncts were certainly common as foods and sweeteners in the period, but precise brewing ratios were rarely preserved. This made primary sources all the more valuable.

Eventually, I turned to the Ebers Papyrus, one of the longest surviving Egyptian medical texts. Written around 1550 BCE during Egypt’s New Kingdom, the papyrus was purchased in Luxor in the 19th century but likely originated in Thebes — the city we now call Luxor — at a time when the Temple of Karnak was rising as one of the largest sacred complexes in the world. This was the era of Amenhotep I, when Egypt was reemerging as a powerful, unified state after the expulsion of the Hyksos.

The papyrus contains hundreds of prescriptions, many of which mention beer both as nourishment and as a vehicle for plant preparations. Crucially, it offered not only lists of ingredients but also amounts. This allowed me to analyze and organize the data, identifying the most common adjuncts and their typical proportions.

After reviewing the recipes, removing ingredients that appeared rarely, and comparing the amounts of more common ingredients across different entries, I settled on eight adjuncts. These would function much like an ancient form of gruit, the herbal mixture once used to flavor beer before hops became dominant. The papyrus helped ground the project in a text that has survived more than three millennia and offered a rare glimpse into the culinary and medicinal practices of the time.

Still, there was another challenge. The names of ingredients listed in ancient texts do not always correspond neatly to the plants we know today. To ensure accuracy, I cross-referenced the papyrus with Dr. Howard Carter’s notes on the botanical specimens found in the tomb of Tutankhamun, who died in 1323 BCE. By comparing the recipe with the archaeological record, I was able to confirm the identity of the ingredients and then purchase them from sources as close to the Levant as possible. With the recipe finalized, I prepared to brew a 10-gallon (38-L) batch. This step was crucial because without careful cross-referencing, the project could have easily slipped into guesswork rather than scholarship.

The backbone of the beer was purple Egyptian barley, 10 lbs. (4.5 kg) in total. Barley has always been the primary fermentable in beer, and archaeological surveys in the Nile Valley routinely recover barley from New Kingdom layers. Experimental malting of ancient landraces has shown high variability in enzyme activity, so using a heritage-type barley was a reasonable way to approximate the past. Scholars have estimated ancient beer to range from very low to relatively high alcohol content, so I chose a middle ground of about 5% ABV. This strength seemed plausible for both everyday consumption and special occasions. Fortunately, a local source was able to provide heirloom purple Egyptian barley, making the choice both historically grounded and practically feasible. Choosing this heritage barley was a way to echo the flavors of the past, since the character of the grain itself would have shaped the beer as much as the brewing process did.

To complement the barley, I added 5 lbs. (2.3 kg) of emmer wheat. Emmer was another grain commonly identified in ancient brewing, and malting it seemed appropriate. I also chose to acidulate and smoke the emmer, reasoning that the fires used to heat the wort in antiquity would have imparted a smoky flavor while also offering some antimicrobial protection. This aligned with targeting a sour profile consistent with warm, open fermentation. The smoking process was simply a reflection of necessity in the ancient world, but in this case gave the beer a rustic quality that modern drinkers often associate with artisanal craft brewing.

I considered brewing the mash in a clay vessel to mirror ancient practice, but ultimately used modern equipment for safety and temperature control. Archaeological evidence shows that Iron Age kilns were capable of firing pottery to high strengths — strong enough to withstand repeated heating — and even early glass production was underway in the Near East by the 9th century BCE. While glass was mostly used for ornaments and small vessels, its very existence demonstrates that artisans of the time had mastered high-temperature control. Some experimental archaeologists suggest that ancient brewers may have dropped heated stones into the mash to raise temperatures, a method that leaves telltale scorch marks on ceramics. Acknowledging these possibilities gave the project a deeper sense of plausibility, even if the recreation ultimately relied on stainless steel rather than clay.

The adjuncts added complexity and depth. Four cups of desert dates, also known as Egyptian balsam fruit, contributed sweetness and richness, much as they still do in porridge today. Four cups of golden raisins, purchased from Israel to remain geographically authentic, provided another layer of fruitiness. Four cups of sycamore figs, identified in Tutankhamun’s tomb, added their distinctive flavor; these were sourced from just outside the gates of Karnak Temple in Luxor, linking the figs directly to the city where the Ebers Papyrus was penned not two hundred years prior. Four cups of Yemeni Sidr honey, derived from the Christ’s Thorn tree also found in Tutankhamun’s burial goods, connected the recipe to the same New Kingdom world that produced both the papyrus and the Valley of the Kings. Two cups of prickly juniper berries lent a resinous note, while two cups of carob fruit added sweetness and body. Half a cup of black cumin introduced a subtle heat that highlighted the floral notes, and half a cup of Hojari frankincense contributed a powerful aroma that initially overwhelmed the beer but later mellowed into a beautifully integrated floral character. All of the adjuncts with the exception of the honey and frankincense were added to the boil (those two ingredients were added after cooling the wort below 95 °F (35 °C) to keep the properties present in the wort).

Once the ingredients were combined, the yeast pitched, and fermentation allowed to run its course, the beer was bottled without added carbonation. Some scholars argue that ancient beer was consumed quickly after brewing, but there is also evidence that it was stored for festivals, feasts, and future use. In such cases, preservation would have been necessary, and my decision to bottle and condition the beer for a week reflected this possibility. The week of conditioning also allowed the flavors to meld, softening the sharper edges of the frankincense and balancing the sweetness of the fruit with the acidity of the fermentation.

When the beer was finally ready, I held tastings in a variety of settings. The most common reaction was surprise at how refreshing it was. Again and again, tasters remarked that it was easy to imagine drinking such a beverage after a long day in the desert sun. It was floral, sour, lightly smoked, and gently carbonated — a flavor that lingered in memory. Tasters compared it to a German Gose — light, refreshing, slightly salty, and sour, with notable fruitiness. Some noted hints of apricot alongside the floral finish, flavors that lingered long after the glass was empty.

The beer eventually earned the name “Sinai Sour,” a nod to its Levantine focus and tart profile. It was unlike anything on tap at a modern brewery, yet it felt familiar, as if it belonged to the same long tradition of human fermentation. To drink it was to experience a continuity between ancient and modern practice, grounded in ingredients, method, and result. From the industrial brewers of Iron Age Gath to the household recipes preserved in the Ebers Papyrus, the Sinai Sour echoed a spectrum of ancient beer culture. It was not just a beverage, but a bridge across time. 

Q: I recently watched one of your BYO+ videos about making sour beer. The suggestion to use kimchi for souring beer blew my mind! I’m already making my own kimchi, so I will definitely try this. Here are my questions: 1. Is there any taste difference between using kimchi and the Lactobacilli that I can purchase from a lab? 2. If kimchi works, what about traditionally soured dill pickles, e.g., Strubbs?
— Gord Maxwell, via Live Chat

Mr. Wizard Says…

A: I recently talked about this during a BYO Live Chat and thought it would be worthwhile to share some expanded thoughts in writing. Let’s start with the idea of using kimchi as a source of bacteria for making sour beer. As a probiotic-rich food, kimchi is a well- established source of various microorganisms believed to promote gut health (Indigenous Fermented Foods for the Tropics is a great reference on this). These microbes, many of which are lactic acid bacteria, also happen to be useful in the production of sour beer.

The primary organisms responsible for kimchi fermentation belong to the gram-positive, acid-producing Lactobacillaceae family of bacteria, often referred to more simply as lactics. This large and diverse group of bacteria is naturally found in many places, including grains, fruits, vegetables, and even in puddles of fermenting spilled milk. One particularly interesting trait of lactics is that many are heterofermentative, meaning they produce multiple byproducts during fermentation. Depending on fermentation conditions, these byproducts typically include lactic acid, ethanol, and acetic acid. This contrasts with homofermentative lactics, which mainly produce lactic acid. That’s enough nerding out for now. 

These days, most sour beers are produced using one of two general approaches: Either by purchasing lab-grown cultures or by channeling your inner Tarzan and wrangling wild bugs. Traditional sour beers rely heavily on the Tarzan method, where wort is naturally inoculated by airborne microbes, ingredients, and the unique microflora found in the brewing environment. One of the best-known examples of this method is used by Brasserie Cantillon in Brussels, Belgium. They are legendary for their exceptional wild ales, which have been brewed using largely unchanged techniques for nearly a century. Their brewery sits tucked away in a charming neighborhood surrounded by butcher shops, cafés, and rows of townhouses, blending the old-world craft of spontaneous fermentation with the bustle of modern life. 

In more recent years, brewers have adapted this traditional approach by using fermented foods — especially yogurt and kefir — as alternative sources of bacteria for kettle sours. Although these cultured dairy products are often made with blends of commercially available bacteria, to the brewer they are still considered somewhat wild, since the exact composition of the cultures isn’t usually known when added to wort. This adds a layer of unpredictability, which can be both exciting and risky. 

Over the past 25 years or so, access to specialty cultures of bacteria and yeast has grown dramatically. Today, brewers looking for consistency and control in their funky beers have a wide range of commercial options. In the early days, most of these lab cultures were blends of organisms found in traditional Belgian lambics or blends intended to approximate bugs found in lambics. As time went on, the push for more predictable and faster souring methods led to the rise of kettle souring. This process is popular because it allows brewers to keep the souring bugs contained in the brewhouse, rather than introducing them into the fermentation cellar where cross-contamination is a concern. 

Because malt is such a rich source of lactic acid bacteria — including Lactobacillus delbrueckii, which is homofermentative, and Lactobacillus plantarum, which is heterofermentative — many early kettle souring techniques relied on bugs cultured directly from malt. Today, however, brewers can easily purchase pure lactic cultures from yeast labs. These have largely replaced wild-cultured sources, especially for brewers seeking repeatability and ease of use. 

More recently, lactic acid–producing yeast strains have gained popularity. Lachancea thermotolerans is a naturally occurring yeast that produces both lactic acid and ethanol and is now available to homebrewers and commercial brewers from yeast labs such as Escarpment Labs and Lallemand. Lallemand also offers a genetically modified Saccharomyces cerevisiae strain known commercially as Sourvisiae. This strain has been engineered to express the gene for lactate decarboxylase, an enzyme that converts pyruvate to lactic acid. The main advantage of using Lachancea or Sourvisiae in sour beer production is the simplified process compared to kettle souring, with no bacteria introduced into the cellar. 

All of this helps explain why the idea of going Tarzan with kimchi as a source of lactics is so appealing for brewers looking for an adventure. Fresh kimchi juice contains a healthy population of lactic acid bacteria. According to the kimchi chapter in Indigenous Fermented Foods from the Tropics, cell densities in kimchi typically range from 100 million to 1 billion cells per milliliter. That’s an ideal range for brewers looking to propagate a strong bacterial culture for use in beer. You’ve got plenty of biological firepower in even a small splash of kimchi juice to propagate for use in brewing. 

Kimchi is just one of many fermented foods that can be used to wrangle bugs for making sour beer. My general advice is to start with foods that taste good to you. If you wouldn’t eat it, don’t brew with it. Live sauerkraut, buttermilk, and dill pickles are all viable sources of lactics. 

One final, important tip: If you’re working with heterofermentative lactics, avoid creating conditions that lead to the production of acetic acid (aka vinegar). These bacteria only make acetic acid in the presence of oxygen, so be sure to minimize oxygen exposure during the souring phase

Sour beer is rising in popularity, but not everyone has the patience or confidence to allow wild airborne yeasts and bugs do the job changing your clean wort to a sour beer. In the last decade several brewing techniques as well as products have allowed brewers to speed up the process while also achieving reliable and repeatable end results with their sour beers. Brew Your Own Magazine’s Technical Editor and Mr. Wizard Columnist Ashton Lewis walks you through the faster ways to get your own homemade sour beer in your glass.

pH might not be the most effective method for measuring the perceived sourness when brewing beer. Due to various acid strengths and the buffering capacity of different worts, titratable acidity (TA) is the true test. Measuring titratable acidity is an incredibly useful and practical way to really discover the true sourness of your beer. TA measures free hydrogen ions and hydrogen atoms bound to organic acids, meaning that the reading directly correlates to the amount of acid that has been produced during fermentation. Learn more from Omega Yeast’s Innovation Brewer, Chris Bernardo.

CHRIS BERNARDO
INNOVATION BREWER, OMEGA YEAST

Click below for a PDF of this session’s presentation slides:

https://byo.com/wp-content/uploads/Titratable-Acidity-Vs.-pH-Nanocon-2023.pdf

Ordem e Progresso (Order and Progress) is the national motto of Brazil, and is the text on their famous green, yellow, and blue flag. I think that phrase also applies to how Brazil’s internationally recognized beer style, Catharina sour, has evolved over the last several years. I’ve been a witness to this history since 2017 and would like to report on what I’ve seen and how it’s currently made.

At its essence, Catharina sour is a fruited sour beer. It has a simple grist containing Pilsner malt and wheat malt, with a clean lactic sourness and a vibrant fresh fruit character. Light in body, high in carbonation, restrained in alcohol, and dry in the finish, the beer is super refreshing in the warm tropical climate of Brazil. The fruit itself is often tropical, but is really just that which is fresh, seasonal, and local in their country. I like to compare it to making fruit meads in the U.S. — when the good fruit is in season, back up the truck and load it up, because you’re going to use a lot of it.

Catharina sours can have herbs and spices too, but only in support of the fruit that is always the primary sensory experience. The bitterness is kept purposefully low, below sensory thresholds, and late hops are not used. The sourness is clean, without funky or vinegary notes, and is mostly used to balance the fruit and malt flavors. The beer should not be heavy, sweet, or strong, as these would hurt its drinkability. The acidity should be pleasantly tart, not a strong, biting note – certainly less sour than most lambics and gueuzes.

The Beer Judge Certification Program (BJCP) Style Guidelines has Catharina sour in the local styles appendix as Style X4. It could be judged with Category 29 Fruit Beers, or with the 28C Wild Specialty Beer using the new 28D Straight Sour Beer as a base style. It should not be judged as a variation of Berliner weisse since those beers are lower in gravity and could contain Brettanomyces.

A Brief History

Catharina sour is an intentional style, in that it was purposefully created as a beer to showcase a national identity. Similar fruited sour beers from several Brazilian regions existed before the style was defined, but those beers were generally treated as unique examples. In 2015, craft brewers and homebrewers held a workshop to formally define the style in the Brazilian state of Santa Catarina, which is what gives the style its name. I encountered the style during a trip in 2017 where it was already gaining a foothold commercially and in competitions. A locally produced style description was being used at the time, before it was published by the BJCP as a provisional style.

In the 2021 BJCP Guidelines, I rewrote the style description based on my own research and tasting notes from several trips, as well as discussions with brewers producing the style. While the name is associated with one Brazilian state, the beer is made throughout the country. At multiple commercial and homebrew competitions I’ve attended in the last few years, Catharina sour is consistently one of the top 3 styles entered, right up there with IPA. So, this is not a curiosity, it is a mainstream style.

Producing Catharina Sour

For this article, I took a deep dive on production methods by interviewing and sampling beers from several experts. I spoke with Brazil’s only gold medal winner in the American Homebrewers Association’s National Homebrew Competition (NHC), Chico Milani from Florianópolis. I chatted with André Piol, a homebrewer from the state of Espírito Santo who won the gold medal at the Brazilian national homebrew championship this year. I brewed a collaboration batch with one of the best-known producers, Cervejeria UNIKA in Rancho Queimado, and had extensive discussions with their Head Production Brewer, Rudy Fávero. My thanks to all for their assistance.

Brewing Catharina sour is a multi-step process. First, there is the wort production and lactic souring. Second, there is the fermentation. And finally, the fruit is added and fermentation completes. Attention to detail is needed at each step, and the conditions for moving from step-to-step are more based on pH and attenuation than a strict timeline.

Wort production is very simple. Target between 40 and 50% wheat malt, with the rest of the grist being European Pilsner malt. Chico, the NHC gold medal winner, also adds about 5% flaked oats. A single infusion mash from 150–154 °F (66–68 °C) is used for 50–60 minutes, with UNIKA preferring the higher temperature for a little extra body. The higher mash temperature and the use of oats are both techniques to reach the same objective of adding a little extra mouthfeel. The water used is relatively soft with light additions of gypsum and calcium chloride.

The mash pH is about 5.2–5.3, measured at room temperature, and the initial gravity of the wort is 1.048–1.050. Mash out at 172 °F (78 °C) and collect the wort. Boil for 10–15 minutes without adding any hops. Chill to 100–104 °F (38–40 °C). Lower the pH of the wort to 4.5 using lactic acid (this is a precaution against other bacteria taking root before the Lacto gets going, not part of the souring process). At this point, the Lactobacillus of choice is added and the temperature is maintained until the target pH is reached. UNIKA used a mix of Lactobacillus casei and L. plantarum, while Chico and André used L. helveticus. The temperature might need to be adjusted based on the strain of Lacto used. A good reference for various strains and sources of Lacto is the Milk the Funk wiki, milkthefunk.com.

I found it interesting that UNIKA pumped the wort back to the mash tun for the souring phase. They said their mash tun has more precise controls for maintaining a temperature than their kettle. The first phase ends when the target pH is reached, which is typically around 3.1. At the brewery, this takes about three days, which should be similar at home if the conditions are the same.

Phase 2 involves boiling and fermentation. UNIKA used about 6 IBUs of Hallertau Magnum as first wort hops, and Chico used about 7 IBUs of Hallertau Mittelfrüh at 20 minutes. Both used a 60-minute boil, and both chilled to 64 °F (18 °C) and pitched an American ale yeast strain (SafAle US-05 or a comparable yeast). So, this step can be summarized as a light touch of German hops followed by a cool fermentation with a neutral ale yeast. Time spent in this phase can vary, but is usually around four days.

Phase 3 starts when the gravity has dropped and the beer is nearing completion (but is not yet at terminal gravity). UNIKA waits until the beer is around 1.020 and Chico waits until fermentation is 75% complete (a gravity of 1.018). At this time, the fruit of choice is added and fermentation is completed at 68–70 °F (20–21 °C). The time spent in this phase is between 4–6 days, typically, with a final gravity between 1.008–1.012 and a final pH of around 3.0–3.2, although the pH can depend on the fruit used. At the brewery, they cold crashed the beer to improve clarity by setting the tanks to 32 °F (0 °C).

When packaging, carbonate to around 3.5 volumes of CO₂ to give high carbonation. Commercial beer is typically kegged or canned, while  Brazilian homebrew is usually bottled. Be sure to use heavy bottles that can handle higher carbonation. The beer is best enjoyed fresh.

The basic process before fruit is added is a fairly typical kettle sour procedure. I’ve described the common way that Brazilians make the beer, but it should be recognizable to Americans. The difference in this style is how the fruit is selected and used.

Selecting the Fruit

Since fruit is the dominant character in the beer, choosing the right fruit and processing it is the creative part of the operation. When I did the collaboration with UNIKA, they wanted to use a Brazilian fruit called araçá that they grew at the brewery. They used nets to collect the ripe fruit as it fell from the small trees; it looked a little like a cherry and had a single pit, but the flavor was like a cross between guava and apple to me, plus it was tart and astringent. They had used this fruit in past years, but weren’t satisfied with the results (the beer lacked complexity, and it seemed too tart).

I worked with them to consider alternatives and we settled on adding maracujá (passion fruit). My thought was that we could play on the guava-like flavor in the fruit by adding another fruit that also had a related flavor, plus more sweetness. I had also suggested playing on the apple flavors by adding cinnamon, or by using honey. The brewery had a good local source of fresh passion fruit, so that made the decision easier.

When Rudy tasted the finished beer, he said it tasted like “wild guava” (like guava, but with a more complex note) — this was exactly what I was hoping for. And I thought he came up with a great name for the beer, so I suggested we call it that. The final gravity was a bit high but it was definitely not sweet. The acidity tends to cut through that higher gravity. 

Most commercial Catharina sours tend to have either one or two fruits, and may sometimes have a secondary flavor from a spice or herb (or even something more unusual, like coffee). One thing I have observed is that the fruit is selected in season when it is fresh and ripe. It might be frozen after picking if trying to capture a sufficient quantity for brewing, but it is never a canned or processed product. The brewery typically washes and sorts the fruit, and uses a juicer or commercial de-pulping machine (despulpadeira, in Portuguese) to extract the fruit pulp while getting rid of skins, seeds, stems, and other waste. Homebrewers would follow this step manually, possibly using homemade machines or hand tools.

Sourcing seasonal fruit and processing it requires some effort, which is why I likened it to making fruit mead in North America. It’s hard work, but it’s what separates the best examples from the also-rans. Enthusiasts in Brazil reject any kind of cooked fruit character or over-ripe fruit flavor. Heating the fruit during canning or pasteurizing finished commercial beers can create a jammy fruit flavor that seems oxidized to consumers. If you can’t get fresh seasonal fruit, try fresh frozen or aseptic processed fruit.

Balancing the fruit flavors while extracting the freshest flavor is what separates the absolute best examples from the great. I remember judging beers with cajú (cashew), cupuaçu (a type of cocoa), and pitaya (dragon fruit), and with strawberry and guava at events in the last year. The best examples are memorable and often have strong flavors. However, these winners also had the qualities of tasting like a super fresh, complex example of those fruits. I think finding the fruit at its peak of freshness and processing it right away is the key to capturing these flavors.

Chico and André both made beers with cupuaçu and dragon fruit. Cupuaçu is an interesting fruit. It’s big like a coconut, but kind of elongated. It has a soft, custardy interior around large seeds, and has a tart, tropical flavor with hints of banana, pear, chocolate, and pineapple. You use the fleshy pulp around the seeds, but it has a texture like a cross between banana and packing peanuts. You have to use scissors to cut it off the seeds (Chico) or use a homemade mechanical device (André). The device was definitely a homebrew invention, since it almost looked like a chicken plucker.

Don’t be put off if these fruits without English translations are unavailable to you. Brazilians also use berries (strawberries, blueberries, blackberries), citrus fruit (tangerines), and more common tropical fruit like mango, guava, and passion fruit. Dragon fruit shows up in recipes frequently to add a bright purple-red color. If you look through ethnic markets, or search the internet, you may be able to find more of these tropical or unusual fruits.

Selecting the Lacto

In the early days of the style, many brewers were using probiotic drinks that contained Lactobacillus for their souring potential. Since Lactobacillus is used in making yogurt, cheese, sourdough bread, and many other food products, it can be found in many forms. Probiotic supplements (pills) are another source of Lactobacillus. Recently, yeast suppliers are making pitchable Lacto for breweries. There are many different strains of Lacto available, and they can have different flavor profiles and brewing requirements (desired temperature and tolerance for hops). The main point is that the Lacto species aren’t all the same (no surprise, just like strains of Saccharomyces) and you should be careful when substituting. You may need to do some tests to see what you prefer, and what works the best in your brewhouse. UNIKA blends their Lacto, so keep that in mind as an option. One thing that seems consistent, however, is that people pitch about 0.1 g of Lacto per liter of wort. So, scale your usage accordingly.

Final Thoughts

There are parts of making Catharina sour that seem fairly simple, such as the mashing and the fermenting. The critical control points to me are the handling of the Lacto, and the selection and timing of the fruit additions. Once you find a process you like, I think you can just change the fruit and optional spice additions from batch-to-batch. The grain, hops, yeast, water, and bacteria all remain constant, which should help you focus your attention on the primary flavor drivers of the style.

If you are new to kettle souring, just be sure you understand what measurements you will need to take so you have the proper equipment. Homebrewers often like to “fire and forget” their batches, but that really won’t work with this style. You can’t let processes run to completion and expect them to hold for extended times. You need to move on to the next steps, so be ready. It may be inconvenient to delay the next phases, but the conditions need to be right to move from one step to the next.

If you are curious, my tasting notes for Wild Guava were that it was a bright yellow color, wheat head, effervescent. Smells great, with a fresh, tropical, guava character but with an added great, wild, vegetal note. Light acidity on the nose, clean lactic. Tasted of a clean sourness, no bitterness or hops. Light grainy malt, but all about the fresh fruit and sourness. The fruit has a guava flavor but is more tart than the guava fruit. A light lemony sharpness accents the beer. Highly drinkable and refreshing.

I hope you give the style a try once you find suitable fruit and a good source of Lactobacillus. You may want to wait until you have a lot of fresh fruit in season, which is what the Brazilians do. We had to delay our collaboration brew until the fruit was ready, but that was a trade off I was happy to make. As a brewer, you want to put your beer first. 

Catharina Sour Recipes: