Oregon's Other Wild Yeasts
Somewhere in this jar, cells of Saccharomyces cerevisiae, var. Fermentis frolic happily. (Ferment calls it White River yeast.
If I introduce the subject of yeast and offer the words “clean” or “cold,” your mind may turn toward lager. If I say “wild,” you will probably think Brettanomyces—despite the fact that most of the breweries using that genus get pure cultures from a yeast lab. What about common old Saccharomyces cerevisiae? If anything comes to mind, I bet “wild” isn’t it. I mean, the name literally means “brewing sugar-fungus” because humans have used it so long in its domestic form.
The nature of “wild” doesn’t depend on the strain, however, and jillions (a technical term) of wild Sacchs are floating around out there looking for sugary places to land. I recently learned that not one but two Oregon breweries had gone out and collected free range strains of wild Saccharomyces and now use them in their beer. They may one day enjoy a designation like Oregon Ale III at one of our yeast labs, but just a few years ago, they were completely undomesticated, unnamed, and undiscovered.
In Bend, Funky Fauna separated their “feral” Saccharomyces from the blend of wild yeasts and bacteria they use for their wild saisons. A couple hours almost due north, Dan Peterson collected a sample of Ferment Brewing’s wild Sacch in the forests near the brewery’s home in Hood River, and uses it a few times of year in saisons or bieres de garde.
I had initially contacted the breweries for entirely different reasons than discussing their wild Sacchs, but it was striking to hear their stories back-to-back, and learn how different the two yeasts are. This is local brewing at a microscopic level, and it’s a very cool way to experience beer that tastes wholly unique.
Two Quite Different Strains
Both breweries started with a spontaneous fermentation. Funky Fauna makes “standard” beers (lagers, IPAs), but they’re known as wild ale specialists. Most of what they call their “wild saisons”* make use of other ingredients—lavender, wasabi, sarsaparilla root, fruit—but they are all fermented with a culture captured wild. I spoke to Danielle Burns and Michael Frith about their yeast and bacteria blend (“the slurry”), and Michael described initially capturing it in their kettle, lambic-style. They keep it active and reserve it for these exotic beers. But they also had some help locating the Saccharomyces strain within:
“It was a collab with Deschutes and we were going do a mixed culture beer. And, I think just for their sake, they're like ‘Hey can we look at your yeast? Do you mind if we bring it into the facility?’ I told them to go for it, and that immediately sparked my interest. I wondered, ‘While you’re looking at it, is it possible to isolate a strain from it?’ Because I would love to start making some clean beers that are still tied to the same ethos of our saisons.
“So a shout out to Jeremy over there at Deschutes. I don't know what magic he worked, but he did a pretty quick streak test and isolated--I think he isolated two for us. We went with just one of them and brewed on their small system and it was just so estery, so saison-esque. It had lots of banana characteristics a little bit of bubblegum. It was just so exciting that that [yeast] was in our wild culture to begin with.”
They use that strain (Saccharomyces cerevisiae, var Funkiana?) routinely now in their “clean” saisons. It’s a POF+ diastaticus strain; that is, it produces phenols like Bavarian weizen or many Belgian strains, and it finishes out very dry—usually at one Plato (1.003-1.004). It ferments well, and although Funky Fauna prefers beers in the lower range of ABV, they have gone as high as 7.2% without trouble. You can find it in their regular “Feral Series” of beers, some of which are saisons, but some of which are other beers like Florific IPA.
At Ferment Brewing, Dan Peterson had an advantage most brewers lack: a trained microbiologist, he knew he could isolate his own yeast from wild cultures. A decade ago, he took four mason jars with wort up Mount Hood, a volcano and the state’s tallest mountain, leaving them overnight to attract wild cultures. From there, he started tinkering. He started by putting the microbes he collected in an incubator, and then growing up little colonies.
“Then, some of them you could start identifying like, yep, these are bacterial colonies, these are yeast colonies. And then there's always mold at that point, trying cover everything. So as they're growing, it’s a a race to get colonies [established] before the mold takes over. But once those are split up and on their own petri plates, they're free of mold and completely isolated from each other.”
Near the White River, on Hood’s Southeast flank, he collected an especially promising sample.
“I was making little tiny batches of beer—like 10 milliliters, I think—in little test tubes, and again, just with dried malt extract. And then usually after one day in the incubator the little wax sealed film top on them would be all inflated and pop that off and I’d take a little sniff to see if it smells like dirty socks—and in some cases they did. And then there was one that just kind of stood out. I was like, ‘Wow, it's got this isoamyl acetate!’”
From there he did seek out some more help, sending a sample to Imperial Yeast. “I mean, I I trusted that it was safe to to drink it myself from a one gallon jug, but I didn't want to brew a bunch of beer with this mysterious microbe,” he said. “It's just a natural Saccharomyces.”
He then described a fascinating transformation. “It did go through some really kind of interesting morphologies. At first when I was working with it, it had these almond-shaped cells. As I grew it up on petri plates, and then in [use it] in beer, I got these really big, round, plump yeast cells. So I think it was kind of softening up and becoming domesticated. Maybe.”
Dan says it’s an incredibly vigorous strain—even with a small pitch it’s soon foaming all over the floor. “It has this character I love—it's got that little banana note like I mentioned [the isoamyl acetate]. It has this citrusy, lime-like character. That's that's pretty unique.”
Amazingly—to me, anyway—it is neither POF+ (or anyway, “it doesn’t have that farmhouse phenolic character”) nor is it a diastaticus strain. It ferments out to 2.5 P or so. Because it is so vigorous and characterful, Dan ferments cool for a farmhouse strain, pitching at 70 and bringing it down to 68. Finally, it’s a robust fermenter: the brewery made an 11% biere de garde, and it was no problem for the yeast. The easiest way to taste this yeast is in the annual White Rive Saison they make every year—though you can find it in other beers as well.
I have no idea how well other Saccharomyces strains outside Oregon would do—or even within Oregon, for that matter. The same year Dan Peterson was scattering mason jars over Mt. Hood, Brian Mandeville was also trying to isolate a wild Sacch strain in North Carolina at Fullsteam—and not having the easiest time with it. They had found a number of Saccharomyces strains, but most didn’t ferment very well. They were slow, or alcohol intolerant. He had one of their beers on tap, and it was good—something like a cross between a rustic Franconian lager and a saison. But it wouldn’t ferment beers that were much above 5%.
Yet hearing about these beers, and especially the one Dan found at Mount Hood, strongly recalled the kveik yeast I’d encountered in Norway. They’re also vigorous fermenters, generally not POF+, and not diastaticus. I am not suggesting any direct connection—though when I think about the forested lands of Western Norway, which reminded me so much of Western Oregon, I wonder if there might not be a different kind of connection.
We humans know a lot about malt and hops—not everything, but quite a lot. Yeast, the brewer’s little helpers, have always been a more inscrutable part of process. That’s especially true when breweries leave the labs and start gathering cultures from their locations. I love that even at this late date, we’re still experimenting with new yeasts, and making fun new discoveries.
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* We do not have a good name for this category of beer. Funky Fauna calls theirs “wild saisons,” while others go with “mixed-fermentation” or “wild ales.” I recently finished an article for Craft Beer & Brewing—the reason I was speaking to Michael at Funky Fauna—and Joe Stange, the executive editor there, suggests “modern funk,” which I wholeheartedly endorse.