WY 2124 I have lost count after 15 generations. I really only buy a new pitch when I have a hiatus, or for no good reason at all but I figure it must be time. It'll go a looooong time. Let me know how it goes! FWIW 3-5 gens is where I find 2124 (or anybody's version of 34/70) starts to act normal, having adapted from lab to brewing. I should also note I repitch pretty quick ( usually 2-4 days from harvest.)