In ancient civilizations, the transformation of sugar into alcohol was a ritual performed by diviners and seers. Vats of grape juice and sweet grain nectar were left before altars, prayed over by priests and, if given the proper time and alignment, would morph into a satiating and consciousness-altering beverage. The ancient Sumerians took their beer with a hefty dose of spirituality.
These days, however, home brewers and commercial brewers alike have a slightly different relationship with their beer. Not only do they have access to a plethora of different yeast choices, but many commercial brewers like Ninkasi keep close tabs on their yeast by way of labs and chemists. Commercial breweries also tend to have so much yeast that it’s spurting out of their tanks by the gallon.
Yeast, as any home brewer knows, is the most expensive ingredient involved in the brewing process. So nowadays it’s standard practice for a homebrewer to sterilize a Mason jar, bring it down to a local brewery and get a free batch of house yeast.
Why does this hook-up exist? Why would a mighty commercial brewer take time away from brewing to help some mere homebrewer?
“It’s definitely related to Jamie’s home brewing experience and his neighborhood-friendly methodology,” Ninkasi cellar supervisor Louie Carter says. He is referring to Jamie Floyd, Ninkasi co-owner.
Ninkasi started with a standard English ale yeast, Fullers, and has been selecting the best qualities in that yeast ever since. This yeast is also noticeably different now than when it was first being cultured, no doubt swayed and morphed by the environmental conditions of the Whiteaker.
“Generally, we’ll select the healthiest or best-performing, best-tasting yeast,” Carter says. “If it coincidentally goes up above our normal 10-20 generations, then we might keep it [to reculture with].”
In brewing, a generation is equivalent to one batch of beer. After the yeast has completely metabolized all possible fermentable sugars in a batch of beer, it can be used for reculturing another batch. For Ninkasi, this can happen nearly 20 times before they deem the yeast unviable and start a new yeast culture from a library of yeasts. Yes, that’s right, they have a library of yeasts.
“We have a lab here, and every time we pitch we’ll do a cell count and viability check and that’s mostly what we base our preferences on when we harvest,” Carter says. “We also have the beginnings of a yeast bank. So we basically have our own library of whatever yeasts we want.”
Selecting strains of yeast ensures consistency in brewing and, at near craft-brewing size, as Ninkasi is, it’s a necessity.
“I would say that [the yeast] has adapted to our style of beers,” Ninaksi head brewer Mark Henion says. “With the higher hop loads and alcohol levels, I think it is fair to say only the strongest will survive.”
Ninkasi’s yeast is as domineering as the brewery’s beers are delectable to the palate. For home brewers, that means that fermentation time, depending on yeast-to-wort ratio, will be shorter, and attenuate well. For most brewers in the Northwest, hopheads and the like, that’s exactly the desired effect.