I’ve just finished bringing my first batch of washed yeast back to ‘life’ to use in my next brew, a nut brown ale. I saved some S-04 from a Moosedrool clone I made back in February, and 2.5 months later I’ve successfully revived it. Below are the basic steps I took.
To the left is what I had after pouring into the jelly jars. Notice how the entire portion of liquid is a creamy color? After settling out things will look different.
I made a 500 ml (1/2 liter) solution using 25grams of dry malt extract giving me about a 1.020 wort. Some will go up to 1.040, it’s your personal choice. Also, I’m just making a 3 gallon batch, so I only need the amount of yeast from 500ml. If you are making 5 gallons or more, you are likely to need 1L to 2L. A good resource is mrmalty.com
After adding the yeast, I mixed (shook) the living daylights out of it to get some oxygen into solution. I proceeded to mix this every so often when I walked by the kitchen. A stir plate would be ideal, and at some point I’m going to build / buy one.
The picture on the left shows what it looks like after mixing up after about 24 hours from pitching. There is a lot of activity, and it helps to get the CO2 out of solution and allow more oxygen into solution to help the growth.
I didn’t show the pictures of boiling the 8 ounce jars in water, as I’ve lost those pictures.
This makes it easy to save yeast for several months (some have reported 1 year) and cuts the cost of brewing considerably. I now have a Kolsch yeast (Wyeast 2565) put away, and I will be saving some Bavarian Lager tonight when I bottle (Wyeast 2124). I expect to have 6-7 strains saved at a time when I eventually top out, and will try to use each jar within 6 months. I look forward to seeing if I can get up to the 5th generation, and further, and how that could compare to a fresh package of yeast.