reuse safale 04

[Ginwu]

I have some russian imp stout in primary that I pitched with safale 04. What would be a good to use it with next?

 

[aiptasia]

yes, provided the beer you want to brew will taste good using re-pitched yeast from a RIS. A pilsner, for example, might not be a good choice.

 

[Ginwu]

I was thinking possibly another stout. Then I've seen that some just pour the wort directly into the same primary directly after racking. Would this not be a good idea with something with less of an OG? The OG on the ris was 1.074

 

[stpug]

Generally speaking, that would not be a good yeast cake to reuse due to the elevated gravity (1.060 is a good cut-off point). HOWEVER, I've done it and it worked out fine from my perspective (maybe not the best yeast profile in these beers but decent beer nonetheless). The problem is highly stressed yeast, higher dead cell count, more chance of mutation (usually takes a few generations though), and very high cell count (i.e. way way too much yeast). I didn't know well enough back then and would not do it again; I would have planned things better.

If it were me, and I was you, and I was going to do it no matter what, I would wash up half of the yeast cake really well. Let the trub settle out before decanting the remaining yeast. You will end up with a fraction of the original yeast cells but they should be much better cells to work with on your next batch. Not to mention, if you've washed them pretty good then you can use them for basically any type of ale.