Have you ever seen the YouTube videos of drunk monkeys?
Don’t worry—this is not a story about evolution. Or drunk monkeys. It’s about yeast.
Like mold and other fungi we see in nature, yeast is abundant. These microscopic single-cell organisms love sugar and can be found on almost every kind of plant. They gobble up sugars, farting CO2 and pooping alcohol, in a process we call fermentation.
When tropical fruits fall from a tree and begin to decompose, the yeast turn them into little “alcohol shots,” which in turn lead to YouTube videos of drunk monkeys. And when stores of grains like wheat and barley got wet, they turned into the first known beverages we called BEER.
The process of making beer involves three major steps: fermentation, Wort production, and recipe design. All are important. But to quote the slogan of our commercial yeast rancher, “It’s all about the fermentation.”
This is the first in a four-part series about how we make beer at Infinite Ale Works. We will begin with the most important step, fermentation.
Controlling fermentation has a huge influence on the finished product. Yeast produce a range of flavor influencing byproducts at different temperatures. For ale yeasts, temperatures in the range of 64-68 degrees Fahrenheit typically produce spicy phenolic flavors; temperatures in the 72-76 degree range produce fruity esters. For some styles – especially our Belgian style beers – the temperature must be adjusted during the fermentation process.
Lagers use different strains of yeast that ferment at lower temperatures in the range of 50-55 degrees for the primary fermentation. The temperature is then lowered to near freezing—where lagering takes place, creating the fine, textured bubbles characteristic of lagers and pilsners.
“Yeast ranchers” – commercial yeast producers – offer a wide range of yeast styles and can produce the appropriate quantity (cell count) for any size batch of beer. But buying a new batch of yeast for every brew is prohibitively expensive. Thus, craft breweries must become yeast ranchers, too.
Our fermentation vessels are designed to collect the yeast produced by each batch of beer, which can then be used to produce the next batch. The yeast produced by one brew typically produces enough yeast to support several brews with each generation. Craft breweries may use a particular strain of yeast for 10 – 15 generations.
But yeast can easily mutate based on the environment. For example, it may not be desirable to reuse yeast from a beer with high alcohol content, as it may cause the yeast to be less efficient in successive generations. Thus, it is desirable for a brewery to produce several styles of beer using the same yeast strain.
We created our Infinite Trails American-Belgo Pale Ale to fill an important position in our product line and to propagate the yeast we need for our higher alcohol West Floridian Belgian Style Quad. Like many Belgian style beers, the West Floridian uses a significant percentage of adjunct sugars; these sugars allow the yeast to ferment more easily than the more complex sugars created in Wort production. Adding these sugars during Wort production can cause the yeast to get lazy, never finishing its job on the more complex sugars. Thus, we wait to add the adjunct sugars several days into the fermentation process, to prevent the yeast from laying down on the job.
If this all sounds complex, it is. We’ve barely scratched the surface of the subject of fermentation. And it is a subject that deserves more attention because making great beers is all about the fermentation. Coming soon, part two…..