questions about re-using yeast

[bushman101]

howdy,
I've made a batch (cider) where I am re-using the yeast cake from the previous batch. I literally pumped out my cider and put apple juice on top of the sediment.

Fermentation is going well, but I got to thinking....

Will the yeast cake continue to grow? How often can I re-use a yeast cake before I get off flavors?

 

[rlmiller10]

Although I am not sure with cider, with beer you would be seriously over pitching to use an entire yeast cake. Some experiments have shown a difference in flavor with over pitching. Your taste buds get to tell is that difference is good or bad.

As for continuing to grow, yes, each new batch will cause yeast growth, so more cells and more volume. But I would suspect the number of live and active cells would not get a lot bigger. Just more old inactive or dead cells in the bottom.

 

[bushman101]

hmmm....ok.
Maybe next time I will just spoon out a bit instead of using the whole thing.
Thanks

 

[bobeer]

Look up "top cropping" yeast. I used to wash my yeast but now I top crop for 2 generations then I dump it. I find it's much easier than washing the yeast cake to reuse it. I still wash yeast every now-and-then though for a big beer brew day.

 

[madscientist451]

I've pitched cider right into the yeast cake without problems, but usually don't go another one after that. You can still re-use the same yeast, just dump the slurry into a jug and use a portion of it, maybe a quart in your next batch.