While I much prefer to harvest yeast from a starter, this is still a viable option of saving your yeast after a good clean fermentation. Note of caution to not using after fermentation where it was under excessively warm, under pitched, harsh environment, high OG, low nutrients etc etc.
Sanitize all the things.
This is even more crucial than in brewing, as any contaminations will be extended due to the much longer storage time and will be continued through each generation and pitch.
When fermentation is done, and I’m racking the beer from the primary fermentation vessel, I leave a little beer on the cake. This makes it easier to pour, as the cake loosens up in the remaining beer. The actual process I use is pretty simple, as I just do the following:
#How to save your cake in three easy steps Leave some beer on cake. Swish to suspend the yeast. Pour beer and suspended cake into a cleaned and sanitized container. Done!
Optional Steps to slightly clarify saved yeast slurry (Optional) Leave single large container alone for a half hour to settle out the trub and hop matter. (Optional)After heavy trub and hops settles, slowly pour the remiaing liquid and yeast into a smaller (but still sanitized) container so that the thick layer on the bottom of the large container remains behind. New smaller contains can be saved until your next brewday!
To use your slurry
For now I’m using the yeast pitch rate calculator on brewers friend and selecting the “yeast type” to be Slurry. Since I’d rather over pitch than under pitch, I enter 1B cells/ml. That means that in 1C of slurry, I have about 237B cells. http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/