Travels with Barley (20 page)

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 degrees 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 these sugars more efficiently, leaving 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's 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.”

As to yeast rustling: “It's technically possible. With our beer, you could get it from a keg of unpasteurized beer. Now, is that easy? No. Our kegs go through one or two filtrations and then a trap filter that is scaled down below the size of a yeast cell. So any yeast that you found would be a little weird—the cells would have to be extremely small. I don't think those would be the ones you'd want to clone to try to duplicate the character of Sam Adams. Beyond that, there's a lot of liquid in a keg. I think it's a fool's errand to go fishing around in there for a few microscopic cells of yeast. They say there's an atom of Jesus' spit in every glass of water—but go find it.”

Koch gave slightly more credence to recovering viable yeast from discarded spent grains and admitted that theft could always be a possibility. But even that has caveats. “Let's just say somebody swiped some Sam Adams yeast ten years ago and it's been swapped around. It may not be the same yeast anymore. One of the tricky things for a brewer is that yeast mutates and if it mutates very much there is a good chance it will change the character of the beer.” (Brewers, in fact, every so often run a DNA analysis of their yeast to make sure it's the same yeast.) Beyond that, Koch said, many beers, including his strong beers, Triple Bock and Utopias, use multiple strains of yeast. So it wouldn't do yeast rustlers much good if they got only one strain and not the others.

I decided to take the matter of yeast rustling into the heart of a yeast lab, and flew out to Portland to visit David Logsdon, founder and president of Wyeast, the older of America's two commercial yeast purveyors. I found him in new lodgings in a compact, austere two-story building anchoring a small office park in Odell, an abundantly scenic town of 1,800 about seventy miles east of Portland.

Logsdon is a dapper man with a professorial demeanor and mustache to match. He was a food science major and microbiologist who was earning a living in the coffee- and food-import business in his hometown of Portland in the early 1980s when he felt the coming sea change of the craft brew revolution. A homebrewer, he'd been dabbling in yeast rustling himself and ended up with a fairly sizable collection, which he began to share with fellow amateur beer makers. His wife, Jeanette, was also a lab microbiologist doing work for a company that produced animal feed supplements.

“We saw there were lots of brewers waiting to start breweries and we felt we could do things for them,” Logsdon told me. “We were already getting good feedback from the homebrewers so we just threw in the towel of our day jobs and started Wyeast.” (The name, it turns out, has nothing to do with yeast. It's the name of a mythical Indian chief whom the gods, to punish for his part in a destructive love triangle, turned into the nearby natural monument known as Mount Hood.)

What started as a small family affair is now a bustling business with fifteen full- and part-time employees. Wyeast banks “a few hundred” beer yeast strains, Logsdon said. It regularly serves about 500 craft and brewpub customers, a base that may swell by another 500 depending on the time of year. Beer is a somewhat seasonal industry—Oktoberfest and Christmas are prime times for breweries to bring out occasional beers—and Wyeast does a brisk business helping such brewers match yeast strains to their ambitions. The company also ships about 10,000 homebrew yeast packages (most of it these days, liquid yeast, which has begun to push dry yeast out of the market) to homebrew stores every week, making it the largest customer of Fed Ex out of the Portland airport. It now has customers, both homebrewers and breweries, in twenty foreign countries.

Logsdon was so enthusiastic about yeast and beer that in 1987 he even helped found a craft brewer called Full Sail in nearby Hood River, Oregon; the brewery is still thriving, though Logsdon and partners sold their holdings to employees in 1999. Logsdon then began to redevote himself full time to yeast, inspired in part by the knowledge that the developing science of microanalytics was bringing to the field.

It was Wyeast that in the fall of 2002 contracted with an outside laboratory to run gas chromatograph/sniff-port tests on beers to try to get an analytical reading on precisely what flavors and aromas the yeast used imparted to beer. To do this, they brewed up thirteen separate batches using identical wort and fermenting each with a different yeast strain. “There were compounds that were never identified with beer before that they found for us,” Logsdon said. Wyeast will continue such tests, the import being that they open the possibility that existing yeast strains can be pushed and utilized in ways that were unimaginable before.

As for yeast rustling, the more Logsdon explained the yeast business, the more it began to dawn on me that lots of new brewers and perhaps not a small number of old brewers had gotten their yeast that way. Joe Owades had told me that most of the early lager barons came from Germany bearing yeast of sometimes murky origins. “Did they get it from their father or grandfather?” he said. “Maybe. Maybe not. Everyone thinks they have their own particular strain and maybe they do. But nobody knows for sure,”

Thus, veiled as it is in a certain amount of mystery, the Yeast World operates in a state of plausible deniability—a kind of “don't ask don't tell” mentality—that gives cover to yeast rustlers. Moreover, it's not that easy to tell yeast apart: you can't just peer into a microscope and say, “that one is Bud's yeast, that one is Rolling Rock's.”

“It's extremely complicated,” Maribeth Raines-Casselman told me. “The old way to identify the two different beer strains was to throw yeast in wort and see what it made—an ale or a lager. But to tell Bud's from Rolling Rock you need a high-tech DNA lab.”

Logsdon agreed, noting there is a technique called electrophoresis—using an electric current to separate molecules such as DNA fragments from similar molecules—that allows scientists to precisely fingerprint, say, the Bud yeast and tell it from another. But that would only be half of the battle. “As with most trade secrets or even patented or trademarked material,” Logsdon said, “it's up to the owner to sleuth out predatory practices by others. A difficult task—particularly when the yeast can be removed from the product before ever reaching the public. So in reality, it's become a bit of a game of who has whose yeast and what's being done with it and what it's being called.”

Indeed, David Wendell,
Wyeast's technical director, told me while I was there that he'd been approached by a homebrewer not long ago who gleefully announced, “I've cloned some of your yeast!”