After much reading, reviewing and contemplation, I decided to give yeast washing (really rinsing) a shot.
First, what is Yeast Rinsing? It’s simply adding boiled and cooled water to a yeast cake, mixing it up, and pouring into another container. Waiting for the trub to settle out, and then trying to pour off just yeast to another container. At some point, you seal up the containers and put in the frige.
Some people have reportedly been able to re-use yeast by this method up to a year after ‘harvesting’. The key is to use a starter prior to repitching, at least in my opinion.
What is truly washing yeast? I’ve never done this myself, and seen very little written about it. In the Yeast book by Jamil Z and Chris White, it is described as pouring a fairly highly acidic solution into the mixed yeast, which by theory, will kill off the various bacteria that could be present, and also will start to damage the yeast themselves. It’s pitched fairly quickly after ‘washing’ in acid.
So, my first attempt was on some dry yeast that I harvested off a cake from my brown ale. It is S-04, and this is my first use of 04. As far as the S-04, I can describe more about it later on my initial tasting notes on my newly named ‘Deer Balm’ Brown Ale which I should post in the next week (batch #17).
I poured ~ 1/2 gallon of boiled, cooled water onto my yeast cake from my fermentation bucket. After about 30 minutes I carefully and slowly poured off part of this yeasty/watery mix into an old pickle jar. I let the pickle jar settle for about 30 minutes, and after seeing the three layers start to materialize, I slowly and carefully poured the middle yeasty layer into three 8 ounce jelly jars that I had boiled and cooled.
You can see the picture of the jars after 24 hours in the fridge, there is a nice layer of yeast on the bottom and a fairly clear light brown layer of water on top. I hope to use one of these containers in the next 2-3 months, and then harvest THAT yeast cake (generation 2) for future use.