I have reused yeast twice but because I’d like to save some money, and hate throwing away what looks like perfectly good yeast, I’d like to reuse more. I How many times do all of you reuse yeast?
I’ve been reusing my yeast for several years now.
My two normal yeasts are WLP001 and WLP002.
I’ve found that I can get 10-12 repitches from the 001 before I notice any change.
However, the 002 starts to change around pitch number 6 or 7.
While it does save some $, I do it because it gives me a ready supply of yeast.
+1 More than the $, it saves me a trip to the LHBS.
I regularly re-pitch all types of yeast–even yeast that started out dry. I usually stop after about 3 generations. I’ve never noticed any change, infection, or mutation.
You should be able to go at least 7 generations. The key is to use it fresh, within 2 weeks of harvesting. Otherwise you should probably make a starter.
When I buy a vial or smack pack I usually start out with a schedule of what I am going to brew the next several weeks. I may start with a dunkel, then go to a bock then a doppelbock or start off with an ESB then from there go EIPA, Robust Porter and Barley wine. The key is to start lower gravity and stay the same or go up. You probably don’t want to reuse yeast from SGs much higher than 1.065, maybe 1.070.
If I am really lazy I may even start with a very low gravity beer, not make a starter and just pitch 2 packs of yeast per 5 gallons and use that as a big starter for my next beer.