Washing Yeast

One thing I’ve wanted to do for awhile is wash and use my own yeast. Sure it would only save me a few bucks every time I brew, but there’s something about it that seems fun. The problem was I felt like an idiot asking people how to wash yeast after having brewed for going on two years. Well after some research I’ve figured out how, and thought I might post a tutorial for anyone interested in knowing. In fact when I finish this batch of beer it might be cool to do another video.

So why wash and reuse yeast? Well for a lot of people the reasons are different. If you’re going to make another batch of beer the same day then you won’t have any lag time while the yeast start multiplying as there will already be a high concentration of yeast. Reducing lag time supposedly reduces off flavors and makes a better beer. Another reason is if you’re into recycling and self sufficiency then you’re eliminating the need to buy new yeast every time. Also I’ve heard some brewers say that over time the yeast will adapt to your specific brewing environment and help produce more consistent results. So if those reasons sound good to you then next time you siphon off your beer then take a bit of time to reuse your yeast.

When you siphon off your beer you’re left with what’s called a yeast cake in the bottom of your fermentor. Some people will just pitch straight on this. One of the issues though is that’s not just yeast in that yeast cake. There’s also something called trub that’s basically dead yeast, waste, and all sorts of gross stuff that’s settled out of your last batch. Personally the thought of pitching a different style of beer on the trub from a previous batch just doesn’t seem kosher. Maybe it is, but it doesn’t seem that way to me.

So once you’ve siphoned off your beer then you swirl the yeast cake to bring everything into suspension. If you don’t have enough liquid for this add 1/2 a cup or so of pre boiled water to help. Next pour the slurry into a mason jar and rubber band some plastic wrap over the top and stick in the fridge. After awhile it will break down into two layers. The bottom layer is the trub, the top is yeast. There will probably be a thin line in the middle made up of both also. Just carefully pour the yeast off into another container. If you want then repeat the process, then put an airlock on the container and stick it in the fridge. You can store yeast for up to a year, just be sure to make a starter if you plan on storing it.


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