The Quest for the Moonshiner’s Yeast

By David Schmidt

After hours of searching, I found my moonshiner friend in a secluded clearing surrounded by sugarcane fields. The lush forests of Oaxaca, southern Mexico, towered above us. Domingo crouched next to his still, tending the fire. He stood to greet me, his shirt and jeans stained with soot and sugarcane juice. I followed him over to the massive fermentation vats, where gallons of sugarcane juice slowly fermented into tepache.

I peered into the frothy surface of the fermentation vat, where bubbles expanded and burst in the morass, teeming with life. On the rim of the tank, grainy yeast residue glistened in the sunlight, millions of living spores.

This was what I had come for.

Ever since I met Domingo years before, I had been dying to know what strain of yeast he used to ferment tepache. It was an ancient mystery, passed on from generation to generation, back to Domingo’s grandfather and possibly much further. This yeast might represent an unbroken chain, an organism connecting us to the ancient civilizations of Mesoamerica, used by brewers long before Europeans ever set foot on this continent.

I pulled out my pocket knife and scraped the rim of the tepache tank. Finally, after years of waiting, I had collected a sample of the moonshiner’s yeast.

MEETING THE MOONSHINER

Long before I brewed my first batch of beer, I was fascinated by the magic of fermentation. Homebrewing goes back at least four generations in my family, all the way to our ancestors in Russia. My grandfather and uncle kept the tradition alive in California. We understood that beer was a living, breathing thing, a happy home for microorganisms to thrive and multiply.

Meanwhile, I felt a darker fascination with the idea of moonshine. While homebrewing was wholesome and family-friendly, moonshining was illicit and secretive, a sinister alchemy from shadowy hollers and valleys. I had read about illegal homemade liquor in history and folklore books but never thought I’d meet a real-life moonshiner.

That all changed when I first traveled to the remote mountains of Oaxaca. My encounter with a native Mazatec moonshiner would blossom into a friendship of several years and teach me volumes about brewing and the magic of yeast in the process.

The state of Oaxaca is home to some of Mexico’s most diverse and ancient indigenous traditions. At least sixteen major languages are spoken there, the native tongues of civilizations that had developed astronomy and brain surgery long before Columbus first set sail. I had spent years in northern Mexico and spoke fluent Spanish, but I knew next to nothing about these ancient native cultures of Mexico. So in the summer of 2006, I headed south.

I had some friends who hailed from San Juan Coatzóspama, a small Mixtec indigenous community in the mountains. They invited me to visit their hometown, and I accepted. I spent my first weeks there adjusting to country living: chopping wood, working in the coffee fields, and learning the Mixtec language. When I heard of a moonshiner who worked downhill from town, I knew I had to pay him a visit. Two friends offered to walk with me down the mountain.

We left the cloudy, chilly climate of Coatzóspam and descended into the warmer lowlands. After hiking for an hour, the air grew humid and hot. We came to a vast sugarcane field and slowly navigated the towering cane as we simultaneously watched for snakes. I soon caught a whiff of two familiar scents: stale alcohol and fresh yeast working its magic.

We emerged in a clearing among the cane, with a breathtaking view of the surrounding mountains and valleys. A dozen men milled about the clearing; some drank from plastic cups while others cut sugarcane and fed the long stalks into a motorized press, squeezing fresh juice from it.

My friends introduced me to the man in charge of the operation. “Domingo,” he said with a friendly handshake. Like the other people who lived in the lowlands, he was of Mazatec ethnicity. He had a kind face, a thick black moustache, and an affable twinkle in his eyes.

Domingo called out instructions to the laborers in Mazatec, then switched to Spanish for my benefit. “That’s what we use to make aguardiente, the liquor.” He pointed to a simple contraption that stood beneath a makeshift thatched roof. It was composed of two thick metal cylinders connected by pipes and tubes. A low fire burned beneath one tank that was black with soot. This was the still, referred to in Spanish as an alambique.

“But first, we need to ferment the sugarcane juice into tepache.” He pointed out two massive plastic tanks at the other end of the clearing, each holding 1,100 liters of liquid. A few men dipped their plastic cups in to take a drink. “Before you can distill, you need to brew tepache.”

“But people drink the tepache all by itself?” I asked.

“Sure. Lots of people who never touch the hard stuff love to drink tepache. It’s a refreshing drink. Some people like the unfermented sugarcane juice as well, la miel de caña.”

I was fascinated. I explained to him that, in the United States’ moonshining tradition, fermented corn mash was not consumed on its own; it was only a means to an end. Tepache, on the other hand, sounded like a brew all its own.

“It’s not just a drink,” Domingo continued, “it’s medicinal, too. It works great as a cure for any stomach troubles: indigestion, gas, stomachaches. Some people tell me they’ve treated dysentery with it. It’s good for fatigue, too. If you’re exhausted from working in the fields, it replenishes your strength. And some guys have even used tepache to treat sexual problems. Not me, of course,” he winked, “but other men. Want to try some?”

He chuckled and led me over to the two fermentation tanks. I made the mistake of peering down into the brew. A thick layer of wasps swam in the foamy surface of the liquid, wriggling drunkenly.

“They like the sugar,” Domingo said casually. He picked up an old plastic cup, pushed the wasps over to one side, and dipped it into the tank. He handed it to me. “Bottoms up.”

I closed my eyes, put my trust in the power of yeast to triumph over evil, and took a swig.

It was delicious. The tepache had a delightfully sweet, yeasty flavor. Domingo explained that this batch was still at mid-fermentation, with an alcohol content of 5 or 6 percent by volume. I took another sip. The sweetness was wholesome and natural, nothing like the synthetic white sugar and artificial flavoring that go into so many commercial cocktails that I would never be caught ordering. But I could definitely get used to this sweet tepache. I wouldn’t be ashamed to order it in a bar, even if it came in a big blue glass with a tiny umbrella.

After a few sips, I noticed the significant aftertaste of alcohol. I mentioned it.

“That’s what’s dangerous about this sweet stuff,” Domingo said. “You don’t really notice how much you’re drinking. The real trouble is, it keeps fermenting in your gut. You could drink ten cups now and feel totally fine …. But tomorrow morning, you’ll wake up drunk. It’ll ferment in your stomach all night long. And you won’t sober up until the afternoon!”

He then gave me a sample from the second tank, which contained fully fermented tepache. The flavor was more well-rounded and balanced, pleasantly dry with a fruity nose. It was similar to a very dry hard cider—like one made in Julian, Calif.—with one key difference: instead of an apple flavor, the tepache had a slight hint of pineapple. I could immediately taste the high alcohol content. This was a drink to be sipped slowly, not chugged.

“That’s around 12 percent,” Domingo explained. “It takes three or four days to fully ferment. We test it every now and then and take a look at it. When the color is like this”—he pointed to the dark, opaque honey color in my cup—“the tepache is ready. We’ll start distilling this batch into liquor tomorrow.”

“Where do you get the yeast to ferment it?” I asked.

“It’s the same yeast from the previous batch. We always keep it active. We pitch some of the fermented tepache into a tank of freshly squeezed sugarcane juice, and it goes to work right away.”

“How long have you been using that yeast?” I asked.

He shrugged. “Who knows. Decades? Centuries? I learned to brew tepache from my dad, and he learned it from his grandpa. This yeast goes back farther than I can remember.”

I marveled at the thought. While distillation was a fairly modern phenomenon, people had been brewing in Mexico for millennia. “So it’s possible that it is much older? Maybe it even goes back to those ancient cultures, before the Spanish ever got here?”

“Maybe.” Domingo took a sip from his own cup. “Why do you know so much about yeast and fermentation, anyway?”

That was when I explained my own family’s history of homebrewing. His eyes lit up as he realized he was talking to a kindred spirit. We discussed the similarities of brewing beer and tepache: variables in ferment time, temperature control, and excess sediment clogging up the tubes. We exchanged a knowing smile, a look of brewers’ solidarity. We had momentarily crossed all boundaries of time, land, and culture, linked by those first humans who had discovered the miracle of fermentation.

The summer rain started to fall, and I figured I should head back to Coatzóspam before the storm. We said goodbye, and my friends and I began the long hike back up the mountain. It was a terrifying, grueling hour-and-a-half march through the pitch-black Oaxacan night as we sloshed through puddles of mud, slipping and falling as we went. Unseen dogs attacked me, and I beat them off with a staff of sugarcane.

And yet, it was worth it. I had met Domingo the moonshiner. Somehow, I knew that our paths would cross again.

YEAST: SACRED AND NUTRITIOUS

Over the following seven years, I made a couple of short trips back to the mountains of Oaxaca. During one of those visits, I tracked down Domingo and brought him a copy of an article that I’d written about him. (“Viva la Fermentación: Ancient Homebrewing in Modern Mexico,” Zymurgy, May/June 2011.) He proudly tacked it up on the wall of his home and gave me a bottle of aged fruit-infused moonshine as a gift.

Back in San Diego, as I continued to explore ancient brewing traditions from around the world, my fascination with Domingo’s tepache grew. I found an invaluable source of knowledge in Stephen Harrod Buhner’s book, Sacred and Herbal Healing Beers: The Secrets of Ancient Fermentation. Throughout human history, Buhner explains, fermentation was seen as a sacred phenomenon, one that transformed an already revered food or plant into a sacrament:

Eating such a [sacred] plant was an occasion of great reverence, but bringing it together with water and the magic of yeast ceremonially allowed the unique qualities of the sacred to come into the body. “Thus wine or some other fermented beverage becomes ‘the supreme symbol of unity between human and divine.’” When taken in this context, human beings literally become “intoxicated with the god.”²

This idea of the divine and the human coming together in a creative act is common in ancient Mexican spirituality. Author Bonifaz Nuño describes it at length in his analysis of the ritual statue known as Coatlicue. The statue, which to many outsiders looks like a fearsome fanged monster, actually represents a sophisticated and complex theology, a belief in the renewal of the universe through divine and human cooperation.

This sort of co-creation is also what makes the magic of fermentation happen. Brewer’s yeast, that organism that brings about the transformation, has been revered in cultures all over the globe. Buhner’s book describes one Norwegian brewer who always took care to make an offering to the fermentation spirits inhabiting her brewhouse. Before pitching the yeast, she would pour some unfermented wort into the four corners of the building, “for the corner crones.”

Beyond spirituality, however, yeast and fermentation were often revered for their medicinal properties, many of which have now been confirmed by modern science.

Much of the world’s diet is lacking in B12 and C vitamins. Yeasts contain ample supplies of both and are the primary source of B-complex vitamins in many indigenous diets. Furthermore, yeasts synthesize B-complex vitamins. Yeast is high in protein and contains the most glucose tolerance factor (GTF) of any food on earth. This acts with insulin to promote the body’s use of glucose. It can reduce the need for insulin in diabetics and reduces serum cholesterol and triglyceride levels in the elderly. Yeasts also contain trace minerals—selenium, chromium, copper—that are found in many fruits and vegetables.

“Apart from any medicinal or nutritional qualities contributed by hops or other plants used in making traditional beers,” Buhner explains, “the act of fermentation itself creates a powerful medicinal and nutritional beverage.”³ While breads and brews provide nourishment, the yeast used to make them contains its own nutrients that those foods lack. This may have influenced the Jewish tradition of eating unleavened bread during Passover. Along with its ties to the Exodus story, it may be a ritual form of fasting from the nutritious benefits of yeast.

The more I learned about the myriad strains of yeast that exist, the more I thought back to the tepache that Domingo brewed in Oaxaca. What variety might he be using? Could it go back hundreds of years? Could it be a strain that science hadn’t even studied yet? My curiosity grew.

One brewer friend in California told me, “I hate to burst your bubble, David, but it might not be that exotic. Yeast is a tricky thing. It can migrate and reproduce easily. And remember, commercial beers used to be unpasteurized. For all you know, your moonshiner friend’s yeast might have escaped from an old can of Bud in the 1940s.”

The idea dismayed me. Bud yeast, in that artisanal Oaxacan tepache? I longed to know for sure. Finally, eight years after my first trip there, I met someone who could help me find the answers.

I developed a friendship with Rex Garniewicz, an anthropologist and homebrewer. We shared a natural interest in ancient, traditional brewing techniques, and experimented together with making Amazonian “spit beer” out of manioc root (“Would You Drink My Spit?”, Zymurgy, May/June 2021). Rex worked at San Diego’s anthropology museum, the Museum of Man, recently renamed the Museum of Us. When he told me the museum was preparing an exhibit about beer and fermentation, I asked if he might know anyone who could identify a strain of yeast. “Sure,” he said, “I’ve got some contacts at White Labs.”

It was settled. The next time I went to Oaxaca, I would try to collect a sample of the moonshiner’s yeast and bring it back. The quest had begun.

IN SEARCH OF THE YEAST

My next trip to southern Mexico was in June 2013. Once I reached Mexico City, I washed out a couple of small shampoo bottles in which to store the yeast. I sent Rex an email before heading up into the remote mountains and asked for pointers on collecting a sample. He replied:

You can store it in a shampoo bottle or other bottle, but be careful that there is absolutely no soap in it. Soap will break down yeast cell walls and kill the yeast, even a small amount. This is why you wash your hands with soap! Yeast can also be collected in dry “spore form” from the crust around fermentation vessels that have been used for years. Scrape some off with a knife and stick it in a bag.

He also added that if the bottles failed, human beards were great for transporting yeast spores. Thanks, I replied, I’ll stop shaving immediately. I’m headed off to the jungle soon, but I can’t wait to try our spit beer when I get back to San Diego … if I don’t get eaten by an anaconda first.

The following week, I was off to the mountains of Oaxaca. As I took the small bus up to the town of Coatzóspam, I thought about the best way to collect the yeast. I couldn’t just take it, not something that ancient that had been handed down for generations. No, I would have to ask permission. And I would have to make sure the lab only identified the strain; it couldn’t be sold or commercialized.

After I arrived in Coatzóspam, it took me a while to track down my moonshiner friend. Domingo often disassembled and relocated his still for security reasons. To be sure, making unlicensed liquor is not as risky in Oaxaca as it used to be in old Appalachia, where moonshiners were frequently killed by the authorities or by their competitors. Here in Mexico, the federal government has bigger fish to fry when it comes to illicit substances, and small-scale moonshiners are usually left in relative peace.

Still, it isn’t exactly legal, either. I had to discreetly ask around town to figure out where Domingo was working. Finally, the townsfolk gave me some rough coordinates: his still was set up at such-and-such a bend in the road, just off the federal highway downhill from Coatzóspam, right before the road sign for La Soledad. After a couple weeks, I had enough information to track Domingo down. Added bonus: my beard had now grown out long enough to collect yeast spores in case the plastic bottles failed.

I hitched a ride in one of the pickup trucks that served as public transportation up and down the mountain. I hopped in the truck’s bed with the other passengers, sat on one of the thin wooden benches, and surveyed the landscape out the back of the truck. I watched the scenery carefully, looking out for landmarks that would tell me we were approaching the hot lowlands. The unbroken mass of thick highland forest soon gave way to open fields of sugarcane and other crops. The air grew dense and humid, thick with tropical smells and lush greenery.

Finally, I spotted a tin roof just below ground level, with a telltale plume of black smoke escaping from it. That must be the place. I slapped the truck’s tailgate to request my stop, paid my 10 pesos, and hopped out of the truck, backtracking to where I’d seen the smoke. Sure enough, there was Domingo’s entire operation.

He had it set up in a small depression that had been dug out of the earth, just a couple of meters below ground level and tucked out of sight. The tin roof provided some cover and shelter from the rain. The tepache fermenting tanks, two massive plastic drums, stood in the far corner. Next to them stood the twin metal canisters that comprised the still, looking resilient and black with soot; a low fire burned beneath them. At the other end of the workspace, I spotted the motorized press used to squeeze the sugarcane, next to a towering pile of dry sugarcane husks.

One of Domingo’s faithful drinkers was tending the fire under the still. He told me that the moonshiner was working in the sugarcane fields down the road. I walked in that direction until I spotted Domingo’s familiar blue truck parked by the roadside. The din of tropical insects and birds was punctuated by the sound of machetes chopping cane. A young boy carried a bundle of it down the hill, and I asked him if he knew where Domingo was.

“Who, that asshole?” cried a man from up the hillside. “He died, man!”

The voice was familiar. I peered between the shafts of cane and saw Domingo up on the hillside, machete in hand, grinning through his thick black moustache. His clothes were deliciously stained with sugar sap. He hiked down to greet me, I helped him and his son load the heavy bundles of sugarcane into the truck, and we drove back up to his still.

“You know,” he said as we unloaded the cane, “just the other day, I was saying, ‘I bet that Schmidt guy is going to come back any day now.’” I’ve often heard this sort of thing in Oaxaca. Folks speak as if you have only been gone a couple of days, not years. Time flows differently up in the mountains.

We descended into the lowered clearing beneath the tin roof and walked across a spongy bed of old sugarcane husks. The familiar smell of yeast hung in the air and bees buzzed about lazily, drunk on the free sugar.

“Want to try some of the good stuff?” Domingo pointed to the still.

“Just a taste,” I said. I had learned, on previous trips, to give moonshine a respectfully wide berth. “Then I’d better stick to the milder tepache. I need to get home in one piece.”

He poured some of the freshly distilled liquor into the cut-off top of a plastic soda bottle. It was just as sweet and acrid and horrible as I had remembered it. Although he swore that it was only 20 or 25 percent ABV, it burned like fire going down. I wondered if it tasted extra harsh because it was fresh from his still. Another more disturbing possibility crossed my mind: in addition to ethanol, some homemade liquor contains toxic methanol, famous for making drinkers go blind.

Domingo chuckled at the faces I made and walked me over to the fermenting tanks of tepache. “Now this is more my speed,” I said as I smelled the familiar yeasty aroma. He handed me an old, worn plastic cup, and I dipped it into the morass of the fermenting tank. The beverage had a tawny, dark color, with heavy sediment floating in it that gave the impression of liquid sandpaper: wild, gritty, and untamed. This sediment boded well—the yeast would be more likely to survive.

I took a sip. It was the fully fermented tepache, with its familiar, tart, cidery flavor, the tangy bite of live yeast followed by sweetness.

“This is the fully fermented tepache, so it’s a little strong,” Domingo said. “You can cut it with this.” He gave me a plastic cup of fresh, unfermented sugarcane juice, which was refreshing after the tepache. A summer rainshower started to fall and beat a soft tattoo on the tin roof.

We stood around drinking with his son and his friend as we caught up on our lives. After a while, I casually peered back into the fermenting vat. I noticed the thick cake of yeast on top of the tepache and told Domingo how common this was with fermenting beer as well.

“You know what it’s like to brew, Schmidt.”

It was finally time to broach the subject. “Hey, Domingo,” I said, “do you think I could take some of this yeast back with me? I’d like to try brewing a batch of beer with it myself.”

“Of course.” He smiled. “I remember what you said about your family making beer. Take it, from one brewer to another. Just tell me how the beer turns out in the end.”

I pulled out my knife and scraped some residue off the tank’s edge. I took a piece of paper from my pocket, used it to wipe the blade off, and stored the paper safely inside my shirt pocket.

Dry spores: collected.

The rain started coming down hard and pounded on the tin roof. I felt a pleasant buzz from the fourth cup of tepache and slowly drank in the tropical setting: the smoky smell of the distillery fire, the sweet sugarcane aroma, and the rain pouring down around us, shaking the flat, shiny leaves of nearby banana trees.

Domingo and his friend switched to aguardiente while I stuck to tepache. We toasted to each other, to the rain and the forest, to the ancient traditions of the Mazatec and Mixtec peoples. Eventually, Domingo’s friend crawled on top of the pile of dry, pressed sugarcane husks and went to sleep. A couple bees quietly buzzed about his head. I had to admit it looked very cozy. Better judgement prevailed, though, and I told Domingo I should get back to Coatzóspam before dark. He agreed, and poured me a plastic bottle of tepache for the road. This would provide me with a liquid version of the yeast as well.

Sample #2: collected.

His son gave me a ride up to a tiny mountain roadside chapel that provided shelter from the rain. I stood inside the chapel, where I waited for a truck to come up the road. I lit two candles before the Virgin and the Cristo Negro crucifix as silent offerings of thanks for a successful day.

THE JOURNEY NORTH

Late that evening, four hours after I had hitched a ride back up the mountain, I still felt a lethargic buzz. The brew was actively fermenting inside my gut, and the bee and wasp larvae did me no favors. I got back to the house where I stayed in Coatzóspam, unrolled my petate mat, and conked out on the floor. I made several trips to the outhouse that night, each one more rushed and desperate than the last. Still, I had the yeast.

A week later, when I made it to a small internet cafe an hour away, I sent Rex a follow-up email.

I put some tepache into one of my shampoo bottles, but the tepache is still halfway through its fermentation, still bubbling and brewing. Is it recommendable to save the sample at this point, while the yeast is still alive, or let it finish fermenting and then bottle it? I’m going to try both. One difficulty with storing it now is, I keep having to uncap the bottle to let the air out. Any suggestions?

Rex replied with instructions:

For storing yeast: As long as it will be reactivated within a week or so, you should let it fully ferment, then it will flocculate and accumulate on the bottom of a vessel. This “sludge” is live and dead yeast cells, which are best preserved under a layer of beer. For improvising an airlock: you can put a piece of saran wrap or any plastic over the top of a bottle and then use a rubber band to hold it on. As long as it is not too tight, air will pass through the rubber band. You can also poke a pin hole in it, but that is not as desirable, because as fermentation slows, contamination can get in if you don’t cap it right away.

I followed his instructions and tightly closed the bottles after they had finished fermenting. In addition to Domingo’s dry and liquid samples, I had another sample from a neighboring moonshiner, Raymundo. I wondered if his yeast would differ at all from Domingo’s.

The samples all survived the bumpy bus ride down the mountain, all the way to Mexico City. I kept them safely stashed in my backpack for the rest of my stay. Just for good measure, I saved my beard clippings in a plastic baggie as well. Nothing wrong with having a back-up plan.

The next challenge was getting the liquid yeast onto the airplane. Mexico’s airport security wasn’t quite as strict about liquids as the TSA, but they certainly wouldn’t let me take a whole bottle of tepache onto the plane. How to get it past? I bought a plastic bottle of apple-flavored soft drink—similar in color to tepache—and washed it out. I then poured the thick tepache sediment into the soft drink bottle. I nonchalantly carried it in my hand as I walked through security, pretending to polish off my soda. No questions asked. The yeast survived the flight from Mexico City to Tijuana and, with a little luck, the same trick worked with US Customs.

The yeast had made it home.

Rex was out of town when I arrived, so I needed to brew some homemade tepache to keep the yeast alive. I bought some piloncillo brown sugar, also known as panela, the natural cane sugar sold in many Latin American markets in the form of hard, dark-brown cones. I dissolved it and pitched the yeast.

Of course, it wasn’t the same as brewing tepache with fresh sugarcane. It lacked the tang of freshly harvested sugarcane, the fresh mountain air, and the subtle spice of dying wasp carcasses. Still, it did the trick of keeping the yeast alive. A couple of weeks later, I delivered it to Rex and waited to hear back from the lab.

NIGHT AT THE MUSEUM

A month after I returned from the mountains of Oaxaca, the Museum of Man held a reception to inaugurate their exhibit about brewing around the world, aptly named BEERology.

The anthropology museum lies in the heart of scenic Balboa Park. Built in the Spanish colonial style for the Panama-California Exposition in 1915, its profile is a San Diego landmark with its domed cathedral roof and Baroque facade. The iconic clock tower even appears in the Orson Welles film, Citizen Kane.

On that balmy September evening, the museum’s central Rotunda Gallery was filled with patrons and donors, San Diego academics and journalists, community members, and, of course, brewers. Dozens of craft breweries offered samples at tables scattered throughout the museum, and the smell of hops and yeast filled the air. The soft lighting produced an intimate, cozy feel.

I walked around and examined the BEERology exhibit. Some of the display panels quoted my previous articles, in this magazine and others, about Mexico’s traditional brews: the corn beer made by the Rarámuri natives of the Sierra Madre and the pulque made from agave nectar. I found Rex in the Rotunda Gallery. We shared an IPA at the foot of the massive Mayan stelae, recreations of an archaeological site in Guatemala.

I wondered whether Domingo’s yeast dated all the way back to those ancient civilizations and asked Rex if he’d heard back from the lab yet. “No word yet, David. But I’ve sent the yeast in.”

I looked up at the hieroglyphs, the stylized animal figures and deities. At the thought of such an ancient yeast, one that could possibly be new to Western science, I felt a renewed concern. “By the way, Rex, your friends who work at the lab—they’re not going to, you know, sell the yeast. Are they?”

He laughed. “No, of course not. They’re just analyzing it to identify the strain. Don’t worry, nobody’s going to accuse you of exploiting your friends in Oaxaca.”

“Good to know.”

“Unless you want to try and sell it, of course,” he joked.

I replied with my best Indiana Jones impression: “That yeast is not for sale! It belongs in a museum!”

“Well, that can be our next big exhibit. ‘Great Yeasts of the World: bring your own microscope to view them.’” We laughed and had another IPA.

A warm September breeze blew in from Balboa Park. The smell of yeast hung in the air. I couldn’t wait to hear back from the lab.

THE VERDICT: THE YEAST IS IDENTIFIED AT LAST

Months had passed since the museum reception, and I was getting nervous. I started to wonder if my yeast samples had survived the journey to the lab. Had they been dead on arrival? Should I have sent them my beard clippings, too?

Finally, in February of the following year, I heard back from Rex. He forwarded me the email from White Labs: the results were in. They had been able to identify two of the three samples, one from Domingo and the other from Raymundo, the neighboring moonshiner. The samples were labeled Sample #1: Oaxaca (A) and Sample #3: Oaxaca (X).

I took a deep breath before scrolling down to the description of the yeast. I closed my eyes, then read the text:

Both samples were identified as Saccharomyces cerevisiae boulardii.

I exhaled with disappointment. So the yeast already had a name. It wasn’t an undiscovered strain after all. I had been hoping to have uncovered a “new” strain. In my more egotistical moments, I confess, I had halfway hoped that they would name it after me. (Although the more ethical decision would have been to name it after Domingo, or to give it a Mixtec or Mazatec name.) But no, this strain already had a name. Science already knew about it. It was old news.

I called Rex about it. “Yes, David, it’s a tropical yeast, a substrain of the basic brewer’s yeast, Saccharomyces cerevisiae. It’s very common all over the world.”

“Common.” I sighed. “So much for making an exciting new discovery.”

“Look at it this way, though. This is a hearty, tropical strain that occurs naturally. It’s not some commercial yeast that snuck into the tepache recently. They’ve found this strain all across Asia and Latin America. So who knows how long the moonshiners of Oaxaca have been using it? It might go back to those ancient civilizations after all.”

The author Bruhner had described this hearty nature of naturally occurring yeasts and how often they were used by brewers around the world.

Many yeasts have been domesticated. They have been used by brewers and bakers for a very long time—as humans measure time. But like medicinal plants, the wild species are more potent, less liable to weaken. If you compare the power of a wolf—look into its eyes—with a dog, you can see the difference between the wild and the domesticated.⁴

My romantic ideas about the yeast’s history were still plausible. This could hypothetically be the same strain used by ancient brewers. How long had it been used to ferment sugarcane juice in the mountains of Oaxaca? We would never know for sure.

As I read up on this strain, I found one intriguing characteristic: its medicinal properties. They were identical to those that Domingo had attributed to his tepache.

Saccharomyces cerevisiae boulardii has been proven to support gastrointestinal health. It has been used in studies to treat antibiotic-related diarrhea, HIV-associated diarrhea, and gastroenteritis.

The strain was first identified in 1923 by French scientist Henri Boulard, who found it on the skin of lychee and mangosteen fruits. Boulard noticed that people in Southeast Asia would chew the skins of these fruits to alleviate the symptoms of cholera. Part of boulardii’s potential lies in the fact that it produces proteins that inhibit pathogenic bacteria and their toxins. To this day, holistic medicine practitioners prescribe the yeast to patients as a probiotic.⁵

One scientific study, published in the World Journal of Gastroenterology in 2016, examined the medicinal uses of this yeast: “Effects of Saccharomyces cerevisiae or boulardii yeasts on acute stress induced intestinal dysmotility.”⁶ The study found that the yeast did, indeed, mediate the effects of stress on the small and large intestines of adult mice.

Buhner’s book explains how Saccharomyces yeasts, in general, were used as medicine in the ancient world. They promoted normal bowel movements, rejuvenated patients after a long illness, and even formed an antiseptic poultice for wounds and ulcers. “Saccharomyces yeasts were used in standard practice herbal medicine in the nineteenth and early twentieth centuries and were considered stimulant, tonic, nutritive, antiseptic, and laxative.”⁷

Buhner further explains that the process of fermentation itself can unlock the medicinal properties of both a yeast and a brew’s other ingredients. I thought back to the medical problems that Domingo mentioned—indigestion, gas, stomachaches, even dysentery—which could be treated with tepache. They were the exact same conditions that modern science treated with this strain of yeast. The yeast itself is medicine.

I haven’t managed to tell any of this to Domingo. After my 2013 trip, my visits to the mountains of Oaxaca became less frequent. Domingo constantly moves the location of his still, and I haven’t succeeded in tracking him down yet. I long to share the news with him, to tell him how his ancestral knowledge of tepache’s medicinal benefits has been confirmed by Western science. But then again, I don’t know if he’d even care.

I imagine telling him this “exciting news,” as he nods and smiles politely. And yet, for him, it wouldn’t even be news. I didn’t “discover” anything—folks in the mountains of Oaxaca have always known about tepache’s health benefits. This brew is medicinal, plain and simple. And Domingo doesn’t need some distant stranger in a lab coat to confirm what his ancestors have known for centuries.

I am eternally indebted to Domingo for all that he taught me about tepache and moonshining. Many thanks as well to Rex Garniewicz, PhD, for his expertise during this and other brewing adventures.

RESOURCES

• Sacred and Herbal Healing Beers: the Secrets of Ancient Fermentation. Stephen Harrod Buhner, Siris Books, Boulder, CO 1998. p. 63.
• ibid, p. 160.
• ibid, p. 70
• ibid, p. 63.
• Wikipedia article on Saccharomyces boulardii: https://en.wikipedia.org/wiki/Saccharomyces_boulardii
• World Journal of Gastroenterology, “Effects of Saccharomyces cerevisiae or boulardii yeasts on acute stress induced intestinal dysmotility.” Christine West, Andrew M Stanisz, Annette Wong, and Wolfgang A Kunze. Accessed online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192264/
• Buhner, p. 71.

ABOUT THE AUTHOR

David J. Schmidt is an author, homebrewer, and multilingual translator who splits his time between Mexico City and San Diego, California. Schmidt speaks twelve languages and has spent the past fifteen years traveling throughout rural Mexico, Latin America, and Africa in search of ancient folk brews, making him a veritable Indiana Jones of home brewing. (Think Harrison Ford with a beer gut.) He can be found on Facebook, YouTube, and Twitter with the handle “Holy Ghost Stories,” or via the website HolyGhostStories.com.