Pitching on sour cakes

None of my sours are finished yet so I haven't done this myself, but I've heard only good things from people who have. And that the cake becomes more bug-driven and sour over time for what that's worth.

Every time I brew a 5 gal sour batch, I've been brewing an extra gallon and putting it in a separate 1 gal fermenter. Pretty soon when I have four or so of those 1 gal fermenters going, I'm going to blend the beer from all of them together with a little fresh wort, and then I'll have those yeast cakes ready to repitch well before the beers themselves are actually ready. The slurry might be a little different and a little less bug heavy than a cake from a 1-2 year + old sour, but given that I've been fermenting these beers mostly with dregs from sour tastings, the slurry from the small batches should be a lot better than commercial sour blends, and should be grown up considerably from the pitch size of just the dregs.

 

Pitching onto an entire cake, wild or not, is WWWAAAYYYYY over pitching. I recently pitched about 125mL of thick ecy02 slurry I'd saved and that seemed like to much. I'd say about 50-100 mL of slurry (depending on thickness) is what I'll pitch next time for a 5.5g batch. I do pitch additional sacc, at least when I'm using older slurry I've had sitting a while. Fresh probably has plenty of sacc.

 

How old is your cake? Is it a primary cake or secondary?

For repitching my sours (primary for ~ 3-4 weeks, secondary for > 12 months), I've used the secondary cake. With all the time, EtOH & acidity the primary sacc strain is waaaaaaaaay lysed so I pitch the entire secondary cake with another primary sacc strain. This sours more quickly than using denovo yeast/bacteria/dregs.