The Learning Lab series started out looking at ingredients and has now moved on to the brewing process. For the fermentation step, the two most obvious variables are the yeast strains themselves and fermentation temperature. When we covered yeast before (December/January 2019), we presented an experiment comparing multiple strains using the same base recipe. Fermentation temperature has a major impact on your beer’s flavor, but many homebrewers haven’t invested in a controlled fermentation setup. If you do have one, it’s certainly worth looking at the effect that a few degrees can have, especially with German Weizen or Saison strains.
But this article is going in a different direction. Normally, you want to follow best practices to make the tastiest beer possible. You treat your yeast cells gently, so they’ll be as happy and healthy as possible. Instead, we’re going to intentionally make things harder for them to see how they cope with stress. This is likely to create some problem beers. While that might seem like a waste of time and money, the goal is to better understand what can go wrong and how to recognize what happened.
Breaking the Rules
Let’s start by reviewing fermentation best practices. The first step is to pitch enough yeast up front. This reduces the reproductive lag stage, so the yeast cells get ramped up for alcohol production and also supports them against any bacterial competition. Good wort aeration also helps this process.