Yeast isn’t expensive — but it also isn’t cheap! Yeast washing allows you to use the same yeast colony in your next batch of brewed beverages. Save money by investing a little time!
1. Boil water
Simply, boil a few quarts of water then allow to cool to room temperature. You’ll need this in step 4.
2. Harvest your slurry
Rack off your beer/mead/cider/wine from primary into secondary. Swirl it in the carboy to thoroughly mix the yeast, lees, and remaining liquid. You want it to be completely homogenous before moving onto the next step.
3. From glass to glass
Pour the slurry into sanitized mason jars. You only want to fill the jars 1/3 full. You’ll need that last third for…
4. Top it up
Take your previously-boiled but now room-temperature water and top up the mason jars to the neck. Place the lids on tight and shake vigorously for one minute.
Let the jars rest for 30 minutes without moving. A white line will form and begin to move down the inside of the jar. That is yeast beginning to settle on top of the lees.
6. Carefully, slowly, gently
Without much jostling at all, pour the liquid off the top into a clean and sanitized mason jar — leaving the lees behind. The lees can be discarded. Put the lid on the mason jar and place in the refrigerator.
7. Wait again
Let 24 hours go by without moving the yeasty water. The yeast will crash out to the bottom of the jar. Then you can simply pour the water off the top! Your yeast is now ready to be pitched into another batch!
Note: The washing process can be completed again after step 7 by jumping back up to step 4 — and then using a pipet to suction the yeast off the top of the layer of lees at the bottom of the jar. For slurries that may contain strong hops or other flavors, this can produce a slightly less-flavorful yeast colony.