German Brewing

Currently, when I transfer over to spund I'm saving what's left at the bottom of my corny, which is typically about a quart of slurry. I store this in a mason jar in the fridge and repitch the whole thing into my next batch.

I'm curious how many times people are typically repitching and if/when you run into any issues?

I've been doing this for years - for up to four generations after the initial (probably no problems after that, but that's about where I find it starts to look a bit more trub-y rather than yeasty). It's important to minimise hop/break material into your fermenter when you do this. I only pitch about half of the collected yeast cake, so I can actually get far more than 5 batches off one yeast purchase. I always have it actively bubbling in some starter wort (I keep a bit of each batch in the freezer to use for starters.....select something similar to what I'm brewing for the starter). Part of my reason for doing this is that yeast is much more expensive in Australia than it is in the US ($14.50 per smackpack at my LHBS) and ferments are more vigorous with a good pitch of yeast cake. I am a bit concerned now though, with spunding, that I'm keeping the most flocculent yeast (least attenuative), so I'd like to hear from others who've done this for multiple generations with spunding. I'm about to brew with third generation WLP833 - hopefully I don't have attenuation problems!

I have it timed to where I keg the night before brew day and use that fresh slurry for the next batch. I've gone 12 generations this way without any bad results but usually don't go over 6. I also transfer very little trub to fermenter, seems to help yeast cake clean.

Makes sense. Think I'm going to roll with the Ayinger strain as long as I can.

Straight up re-pitching, about 10 generations for me (although, I change strains a lot). You can get 15-20 if you have really good aseptic skills, oxygenate well, use nutrients and transfer almost no trub from the boil kettle. If you are willing to take 1/2 of the slurry you need for your next batch and put it on a stir plate in an appropriate sized starter, then this ensures 1/2 of the cells are new and all are as healthy as possible. With this method, you can essentially keep it going indefinitely.