Excerpted from Travels with Barley
The kit worked so well that two things happened. One: Maribeth started to accumulate a lot of yeast. “One guy alone brought back three separate strains of Pilsner Urquell (the Czech Pilsner that was the world’s first golden, clear beer) and a bunch of Belgian strains,” she said. She would clone-purify the samples, test brew with the clones, and, if they made good beer, store the samples in her lab nitrogen refrigerator for future use and propagation. Soon, she had so much yeast that she found herself with a small mail order yeast business. Second: the kit became so popular that she developed a cheap commercial version of both a capture kit and cultivating kit which she started selling through a third-party vendor. She only recently got out of the mail order yeast business to turn her attention to making a commercial success of Hollywood Blonde, but by then “I felt like I’d gotten rid of a lot of the misconceptions about how this all worked,” she said. And indeed, these days a number of online and corner store homebrew shops carry yeast-capture kits starting at about $7.50. For about $300, including microscope, would-be yeast rustlers can outfit an entire yeast-culturing lab.
And just how common is it for people to actually invest in these things? “It’s not at all unusual,” Bev Blackwood, a member of the Houston-based Foam Rangers homebrew club whom I’d gotten to know, told me when I queried him. “It’s not for the casual brewer. You really need to be lab-oriented since you’re talking agar plates, microscopes, stir plates, and the like. But several Houston-area homebrewers culture their own yeasts and I know of at least one who maintains his own private yeast bank on slants.”
Blackwood, in fact, said he had a yeast-rustling project of his own underway. He’d brewed a batch of beer that seemed to have picked up an infection in one of his bottling lines—meaning that some spoiler bacteria had intermingled with the yeast and given the beer a sour flavor. Blackwood turns out to be fond of a Belgian style of purposelly-made sour ale called gueuze (sometimes spelled geuze) that is originally fermented with wild yeast but which gets its predominant flavors from various “microflora”--i.e. bacteria—that brewers introduce into the fermentation cycle by exposing their fermenting beer to the open air. He had some bottles of gueuze at home so “what I did was to drink the gueuze and then save the crud at the bottom of the bottle, which is composed of the various microflora that have been working on the beer. I used this stuff to dose my new bottles. My theory was that if I was going to have to deal with an infection, it might as well be one that I’d enjoy drinking.” (The beer turned out swell.)
Maribeth, meanwhile, still undertakes special yeast projects: she’d just finished clone-purifying “on a large scale” some Chimay yeast for BJ’s, a large brewpub chain that has an outlet near her. Chimay, a brand of bottle-conditioned Belgian ales brewed by Trappist monks, is one of the world’s most beloved beers among the Beer Geeks; both American craft and homebrewers have gone wild for the style. Getting Chimay’s yeast, however, isn’t as easy as it used to be. “Ten years ago, when I was doing this,” Maribeth explained, “Chimay yeast in the bottle was the Chimay fermentation yeast. Then, they found out these wacky American homebrewers were cloning the yeast and making beer with it--and the American brewers were getting it. So, then they started using a special carbonation yeast for bottle conditioning. Now it’s hard to get good Chimay yeast.”
So where did she get hers?
Maribeth smiled. “I can’t give you all my secrets,” she said.
However, this much is known: both Wyeast and White Labs do in fact sell yeast that the Yeast People will tell you are the actual strains used by many big-name commercial breweries both here and abroad. For a variety of reasons they just can’t be called that. For one, the yeast labs don’t want to rile up the breweries; second, they don’t want to imply that a homebrewer, having acquired a commercial beer yeast, will automatically be able to brew a beer that tastes exactly like the commercial beer in question.
It was this situation that provided my first inkling that beer yeast was the object of such passion, desire, and speculation. I’d introduced myself by e-mail to members of the Foam Rangers club, Blackwood among them, and was directed to their informative Web site. Browsing it, I was intrigued by an essay by Ranger Steve Moore, who had gone to the rather elaborate trouble of putting together a list of eighteen yeast strains sold by the commercial yeast purveyors and, drawing on the collective knowledge of the Yeast People, articulating whose yeast they actually were. One example was a yeast sold under the moniker 1056/American ale yeast and nicknamed Chico.
“Everyone knows it’s the Sierra Nevada yeast,” Moore wrote.
Another, called Irish ale yeast, was clearly the Guinness yeast, he stated. And then there was another dubbed Pilsen lager yeast from “a classic American Pilsner strain.”
“Yeah,” Moore wrote, “from the largest brewery company in America…and the world…somewhere around St. Louis. Throws a green apple/acetaldehyde flavor that is characteristic of Bud, if you aren’t careful.”
When I later talked in person to Moore and Blackwood about this, they said that assiduously mining the yeast grapevine to try to figure out exactly whose commercial yeast was finding its way into the homebrew market was considered one of the great side sports in homebrewing. For the record, the Yeast People will say they could be wrong about such correlations. But when you talk to them in private, these things are considered to be so well known as to be beyond debate. Maribeth, when I asked her what yeast she used in her Dougweiser, said matter-of-factly, “That’s the Rolling Rock yeast.”
Rolling Rock, of course, is one of the remaining surviving regional lagers, brewed by Latrobe Brewing Co. of Latrobe, Pennsylvania.
As to the theories of the availability of Bud yeast, the prevailing speculation is that it had long ago fallen into the hands of homebrewers, who traded it around under the moniker “Amateur Brewer’s Yeast”—or “AB Yeast,” for short, the AB being a wink and a nudge that really meant Anheuser-Busch. It’s a matter of historical fact that Anheuser-Busch was in the baker’s yeast business until 1988; one of the Yeast People told me that for a while the baker’s yeast strain it sold was actually the same as its Bud beer-yeast strain. True or not, AB Yeast ended up in the yeast labs where it is sold under guises such as the one that Steve Moore described.
Beyond that, there are other ways the Bud yeast could have made its way into this quasi-public domain. Bud is pasteurized and filtered before bottling to kill any existing organisms, including yeast, so there’s little chance that yeast could have been cloned directly from the beer itself. But given the tons of yeast that Anheuser-Busch uses annually and the number of people with access to it over the decades, it’s hardly unimaginable that a thimbleful walked out of a brewery someplace one day and into the test tube of a yeast rustler. And, as we’ll see, the possibilities don’t end there. The official Anheuser-Busch position is that the yeast it uses today is from the original strain acquired by Adolphus Busch in 1876 and is indeed proprietary. The company had no comment on whether people have or haven’t cloned it.
***
It’s hard to imagine that brewing had carried on for thousands of years, till the mid-nineteen century, before it gained hard knowledge of yeast’s role, but it did. Thanks to Antoni Leeuwenhoek, the Dutchman credited with inventing the first useful compound microscope in the late 1600s, scientists had for about a century been able to see microorganisms, even yeast. But the prevailing wisdom had been that yeast and other microorganisms were the products of spontaneous generation; in the case of yeast, scientists believed yeast to be a by-product of alcohol, not alcohol a by-product of yeast. Thus, as noted earlier, it was left to Louis Pasteur, in his groundbreaking 1876 book Studies on Beer, to unwind and unlock the science of zymurgy--how yeast do the work of fermentation—and convincingly prove his statement that "fermentation is the consequence of life without air.”
Brewers (and modern-day yeast rustlers) also owe a huge debt to Emil Christian Hansen, a part-time novelist and full-time chemist at the Carlsberg Brewery in Copenhagen, who in 1883 first isolated a single cell of beer yeast and showed that yeast could be propagated and “banked.” Inspired by the work of Pasteur, Hansen had been asked by his superiors to tackle the question of why beer batches often spoiled in the summer. What he discovered was that beer yeast colonies of the time contained good and bad actors; the bad ones were cells that were dormant in the cool weather but sprung to life in the summer heat, throwing off flavors that spoiled beer. The good ones were what would become known as lager yeast—indeed, Saccharomyces uvarum is still sometimes known as Saccharomyces carlsbergensis in honor of Hansen’s work. Until that moment, knowledge of yeast hadn’t meant brewers were in full control of it. Hansen essentially “tamed” the beast and made possible the reliable replication of pure yeast strains (thus giving a huge boost to the unfolding lager revolution).
By one estimate, beer yeast is one of about 600 species of yeast in the world and they exist in every climate on earth. Most are harmless or, like Saccharomyces, beneficial, though some are linked to food spoilage. A few, like Candida albicans, the strain responsible for common yeast infections in humans, can cause minor health problems (and major ones in people with seriously depressed immune systems).
Yeast may be single-cell organisms but they possess somewhat complicated DNA; they have about 6,000 separate genes (compared with about 66,000 for humans) and sixteen chromosomes (compared with our twenty three.) They also have their equivalent of the Human Genome Project, called the Comprehensive Yeast Genome Database, which is an amplification of work completed in 1996 by a consortium of more than 100 worldwide research labs. That year, scientists finished the DNA sequence mapping of Saccharomyces cerevisiae and came to the startling conclusion that a goodly number of the 6,000-plus yeast genes have considerable similarities to human genes and perform many of the same functions. The import of this? It gives scientists a potent new tool to comparatively study human gene functions—the vital role certain genes play in switching on or off other genes, for example—with implications for pinpointing the causes and perhaps cures for more than forty diseases, including cancer and cystic fibrosis.
None of this is particularly surprising to the Yeast People, who constantly marvel at yeast’s adaptability across many environments, including beer fermentation tanks, and the elegantly efficient way that fermenting species do their work. S. cerevisiae, or ale yeast, is known as a top-fermenting yeast because of the propensity of its colonies to clump together and, aided by the surface tension of wort, to float near the top of fermentation tanks, where its work is evident by a frothy, brown head created by the carbon dioxide it gives off. It typically ferments at 55 to 75 degrees F.
For reasons not fully understood, S. uvarum, or lager yeast, doesn’t congregate and clump as well. It therefore floats in suspension far deeper in the wort column (wort, again, being the sweet, amber liquid extracted from the barley mash). When its fermentation stage is done, it goes dormant (as all yeast eventually does) and settles out far more readily at the bottom of the fermentation tank. This is one explanation, absent filtering, why lagers clear more easily than ales. Lager yeast also ferments at much lower temperatures—from 34 to 55 degree F—explaining why it was discovered so late in beer’s history and why, until reliable mechanical refrigeration came along, it was so much harder to deploy and control.
But the major difference between ale yeast and lager yeast is what they dine on. Wort, the amber extract produced by mixing cooked barley-malt mash with hot water, is rich in sugars, notably monosaccharides, disaccharides, and trisaccharides. It’s a slight oversimplification but essentially lager yeast metabolizes more of these sugars more efficiently, and with fewer by-products, than does ale yeast, giving lager a taste that, to most palates, is drier, crisper, and cleaner than ale. Conversely, it’s the residual sugars and by-products that ale yeast leaves behind that account, in part, for its earthy, fruity, more complex taste profile.
Another person with an informed opinion of these matters is Joseph Owades, founder of the Center for Brewing Studies, a brewery-consulting concern in Sonoma, California. The craft-brew revolution is an ale-yeast revolution and most Yeast People are Ale Heads. Owades most certainly isn’t. Now in his eighties and still a beer consultant, he is the man credited with inventing that contemporary lager juggernaut, light beer, back in the early 1960s while working for the Rheingold Brewing Co. (Rheingold, a big Brooklyn lager maker, went bust in 1976 but has been brought back on a much smaller scale by a descendant of the founders.) Owades’ brewing breakthrough—totally unheralded at the time—came from his extensive knowledge of yeast and its synergistic relationship with barley malt. Owades noticed that barley lacked an enzyme that would allow it to release all of its sugars for yeast to feed upon; by introducing a chemical enzyme to complete that process, he was able to engineer a beer that, when it was finished, contained zero fermentable sugars (and thus far fewer calories than regular beer.) The yeast to do that job was the highly efficient lager yeast, Owades told me, not that picky ale variety. (If the yeast strains were music, Owades would tell you that lager yeast is elegant, melodic jazz while ale yeast is all funk and blues.)
Rheingold put out this beer, called Gablinger’s, as a diet beer for men and it flopped. Meanwhile, Rheingold literally gave the formula to Chicago’s Peter Hand Brewing Co., which brewed its own version called Meister Brau Lite. It didn’t go anywhere, either. But in the early 1970s, Miller Brewing Co. bought Meister Brau Lite from Peter Hand, renamed it Miller Lite--and the rest is history.
“What did we know?” Owades said by telephone during an interview from his home in Sonoma. “We were in Brooklyn, they were in Chicago. The beer didn’t seem to be going anywhere. So we gave the recipe away.” (Owades is still in the light beer game, however, recently collaborating with Jim Koch’s Boston Beer on its first ever Samuel Adams Light.)
Owades doesn’t dispute the basic science of yeast rustling but he thinks there are too many variables in what different strains of yeast do during fermentation to make cloning an effective way to actually replicate somebody else’s beer. Besides the differences in the way ale and lager yeast ferment sugars, yeast also produces a staggering 1,300 other compounds loosely known as congeners. These include esters, which can throw off flavors that approximate things like green apples, bananas or vanilla, and sulfur compounds, which can give off earthier, barnyard-like aromas.
“All these companies, Bud, Coors, and Miller, have their yeast from way back and they all are a little different in the congeners they produce,” according to Owades. Moreover, he said, congener production can vary within a yeast strain itself, depending on a number of variables, fermentation temperature and available sugar, among them. So even if someone had Bud’s yeast and knew exactly how much rice, malt, and water to use, they still might miss badly on cloning Bud if they get these other variables wrong.
On the other hand, Owades said yeast security is a real issue since all breweries make more yeast than they need and have to dispose of it some way. “The little guys dump it down the sewer when nobody’s looking,” he said. Middle-sized brewers throw it out with the spent grains from the mash tank (the grains often become cattle feed.) But such grains leave the brewery at about 160 to 170 degrees, making it likely any yeast mixed in would die. Some big brewers sell surplus yeast to food companies. “Campbell’s Soup buys a lot of surplus yeast from breweries on the East Coast,” Owades told me. Still, with all that yeast floating around it’s not implausible that some viable yeast ends up in foreign hands.
One afternoon over beers in Manhattan, I ran all this by Boston Beer’s Jim Koch to get the brewer’s perspective.
“Yeast does certainly matter,” he told me. “If you look at the flavor profile of Bud, Miller, and Coors, I’d say the major difference is the yeast. That little green apple factor in Bud? That’s a yeast deal. As for our beer, it’s pivotal. Our yeast is proprietary. We consider it a secret. I literally don’t know its exact origins. I don’t know whether it was cultured from some unusual German brewer. I know you just don’t find these things lying around.”
Yeast Rustlers 2...