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.
Step 1: I poured preboiled and cooled water into the my fermenter (plastic bucket in this case) swirled around the yeast, water, and other trub that was left over after bottling.
Step 2: After letting the water/yeast/trub mixture sit for about 20 minutes and seeing some layers (see above) I carefully poured part of that into a glass jar. I now let this set for about 20 minutes. Now, I did see separation into 2 layers, but not the 3 I really wanted. I would have liked to have seen a thick layer on the bottom (dead cells, trub, hops, etc) that I could have avoided. Instead I had a clear top layer.
Step 3: Moving along with what I had, I carefully poured the thick cloudy mixture into three 8 ounce jelly jars that I had preboiled (with the water I used to start the process of washing).
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.
Step 4: I put tape labels on the top of the jars denoting what kind of yeast, the date and what ‘generation’ this was (this was the first generation). I then placed the jars in the refridgerator for long term storage. To the right you can see what the jars look like after being in the fridge and settling. They should look this way within 24 hours, if not sooner.
Step 5: So now we move ahead to about 3 days before you want to brew. To the left you see what my jar looks like after pouring off the clear liquid on top, and then mixing the yeast up.
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
Step 6: Pour your 500ml wort that is cooled down into a glass jar of choice. Many use Erlenmeyer flasks, but I’m just going with an extra 1/2 gallon growler I have available. After pouring the prepared wort into the jar, I then pour in my room temperature yeast.
Step 7: well, step 7 and 8 are just pictures with an explanation.
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.
Step 8: This is about it. Within 36 hours the yeast is pretty much done with my 1.020 wort and has definitely grown in size (see the bottom). At this point one could pour off the clear liquid on top and add 1L of new 1.040 wort to get the cell counts up high enough for a higher gravity or larger batch of beer, or just to have enough to sock away in another 8 oz jar if that is what you want. For me, I have stuck this in the refrigerator and will take it out tomorrow morning, and brew in the afternoon.
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.