Struggle, stress and success: Beverages that shine under pressure
I was tasting student-made beers with my colleagues at work a few weeks ago, beers that were intentionally creative and off the beaten path in terms of traditional recipes, and we came to Alyssa’s under-pitched saison.
It was wonderfully fragrant and had the mouthfeel to complement. It was when we started discussing the intention of under-pitching yeast (in other words, stressing the yeast out) that I was struck with a realization. Most of the beverages I work with and teach about all seem to have a similar success story; stressors actually help create a superior product.
I spoke with Victor North, my fellow brewmaster instructor, who explained that in order to extract the more intense aromatic compounds you’re looking for in certain beers (like fruity esters and spice-driven phenolics), you need to create an environment in which the yeast will be under stress. Alyssa put less yeast in her brew than the recipe would typically call for, which leaves the yeast with more sugar than it would normally consume. Although this doesn’t sound too problematic, it is actually very stressful for the yeast. It’s like 10 yeast cells attended a buffet that was intended for 30 yeast cells, and they still ate all the food. The byproduct of stress in this situation is the spicy aromatics that adds to the beer’s character.
A famous German style of beer, Hefeweizen (a wheat beer known for its banana and clove aromas), uses this tactic as well. A specific strain of yeast is used, put under stress, and those specific characteristics come out in the brew. Many home brewers make the error of not stressing their yeast enough when making Hefeweizens, and don’t get that lovely punch of aromatics they’re looking for.
Another way brewers stress yeast for their benefit is by placing it in an anaerobic environment. Normally if yeast is left with oxygen, it will create more yeast. This is useful if you’re making bread, but not when you want to make alcohol. When deprived of oxygen, the yeast will become stressed and create alcohol. As Victor explained, “you are forcing yeast to be creative in its metabolic pathways.” Well done, yeast.
As a wine industry veteran, I’m certainly familiar with the idea of beneficial stress. Grapes grow on vines, which are known to be vigorous. If left with perfect growing conditions (ie. plenty of rain, sunshine, ideal soil conditions and generous spaces between plants), the vine actually gets lazy and goes into a vegetative state, simply growing its leaves and tendrils rather than fruit. In its mind, if it doesn’t have to work, then why do it?
So grape growers will actually deprive the vine to a certain extent, to stress it, thereby refocusing the vine to use its energy for fruit production. By restricting its water, making nutrients scarce in the soil and planting it close to other vines, the vine realizes it doesn’t want to remain in its state, and focuses on reproduction (ie. growing grapes). Furthermore, vineyards that struggle more than others will produce better quality fruit. The berries are more aromatic and complex.
When it comes to tea, both the climate and the altitude that the tea plant grows in contribute to its success. Tea primarily grows in tropical or subtropical regions. When the plant is exposed to stress, it creates a better tasting leaf. Dramatic climatic conditions, like extreme heat in the day juxtaposed with very cool nights, disrupt the chloroplasts in the leaves and trigger the plant to retain chlorophyll in its leaves, thereby improving the flavour. High altitude also does the trick. Tea leaves that grow up in the region of Darjeeling, high in the Himalayan mountains, are prized as “the Champagne of teas,” an accolade well deserved. The leaves grow at an altitude where the air is thinner and are subject to oxidative stress which stunts the growth of the plant. This is actually fantastic for the development of aromatic compounds.
When the tea plant is stunted, growth continues very slowly and the new shoots that are produced contain a higher concentration of aromatic oils that thereby create richer flavours in the tea.
In all of these cases, stress pushes these products past their comfort zone and forces them into a better version of themselves.
However it’s all relative. A bit of stress is beneficial, but too much can be detrimental to yeast, grape vines and tea plants alike. A drought will make a grape vine shut down, under pitching your yeast too much could result in contamination, and planting your tea plants at too high of an altitude will result in erratic environments in which the plant cannot survive.
But I think it’s helpful to remember, as we all try to balance our busy lives and daily stressors, that a little struggle sometimes isn’t such a bad thing. It can change the course of our path, bring out things in ourselves that we didn’t realize were there, achievements we perhaps didn’t know we were capable of. Even the smallest yeast cell can.