(Probably stupid) yeast cake question

From all these posts I just assume you can throw the next batch onto your previous yeast cake, but do you have to clean anything out or stir up the yeast cake to invigorate the buried yeasties? I searched around but didn't really find any clear answers.

you can just pull the beer off the yeast cake and put a new beer on top, the only bad part is you will get some of the flavor from the other beeri do it with a secondary but i won't do it with a primary because i always have some hops on the bottom of my primary.


the suggestion is not to rack a lighter beer on top of a dark beer and higher gravity beers some times will stress yeast so some don't like to rack onto yeast that was stressed as such.

squeeky is absolutely right

However, you should probably wash the yeast. You get mostly viable yeast instead of residual proteins and autolysis yeast. Here's a thread you should definitely read https://www.homebrewtalk.com/f13/yeast-washing-illustrated-41768/

Thanks again guys. My first beer is relatively flavorless and as such shouldn't impart much of anything onto my next beer.

Still a good idea to wash the yeast I think. Get the old trub out of there. Unless you are going to brew a porter or stout or something...then it will just make it more "complex".

i understand the idea of washing the yeast before pitching, but what if you are using it for the same exact beer (or at least the same style with a slight variation?) i am going to be starting a house pale ale and want to have it as my experiment beer to make sure i can replicate procedures and perhaps tweak a thing here or there to perfect my recipe. can i just pitch right onto the cake then? i have read that there may be too much and you are overpitching...should you just dump some out, or switch some of it into a new carboy? just a bit confused, but would love to re-use to save time/money. also, is there a limit as to how many times you can use the same cake? if i brewed this every two weeks, how many batches would it last?

The problem with re-pitching onto a cake isn't with the yeast so much, but the proteins and fats that are in trub. When you re-pitch onto the yeast, that stuff is staying behind and breaking down. A wash will just remove the yeast from the stuff you don't want.

You will probably be fine pitching onto the cake with the trub in it, but I think washing yeast is so easy that it is worth doing.

steelerguy said:

The problem with re-pitching onto a cake isn't with the yeast so much, but the proteins and fats that are in trub. When you re-pitch onto the yeast, that stuff is staying behind and breaking down. A wash will just remove the yeast from the stuff you don't want.

You will probably be fine pitching onto the cake with the trub in it, but I think washing yeast is so easy that it is worth doing.

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Good advise that will help make better beer.

You have to remember that using a yeast cake is really overpitching and can be just as bad as underpitching .. Use the Mr.Malty pitching calculator .Mr.Malty

What I have done is to reclaim about a third of the slurry and repitch w/ wort into a sanitized fermenter. At this point you can wash the remains of the cake for future use.

something about pitching onto a cake that doesn't sit right w/ me.

i think i was reading on the Safale FAQ, they reccomend not exceeding five generations...wow, that seems excessive??

I think it's BEST to recover the cake, wash it and pitch it in a couple days. That gives the yeast some time to settle.

However, I've pitched right onto a cake before several times and never noticed anything "wrong" with my beer. I say go for it.

If you're going to use the same yeast again, however, I would def. recommend the yeast washing procedure.

Brew on!

leapdog said:

i understand the idea of washing the yeast before pitching, but what if you are using it for the same exact beer (or at least the same style with a slight variation?) i am going to be starting a house pale ale and want to have it as my experiment beer to make sure i can replicate procedures and perhaps tweak a thing here or there to perfect my recipe. can i just pitch right onto the cake then? i have read that there may be too much and you are overpitching...should you just dump some out, or switch some of it into a new carboy? just a bit confused, but would love to re-use to save time/money. also, is there a limit as to how many times you can use the same cake? if i brewed this every two weeks, how many batches would it last?

Click to expand...

If your goal is replication, you need to control the amount of yeast pitched just as much as you control everything else - malt, hops, etc. - because yeast create flavor-impacting byproducts during fermentation that have an impact on the finished beer. Knocking out onto a yeast cake is abdicating all control over your yeast colony, because I 100% guarantee there's too much yeast there.*

Healthy yeast are important. By carefully harvesting and washing yeast, you can pitch out to a dozen generations or more. By carefully manipulating your harvested yeast, you can pitch the same culture indefinitely, but this involves specialized techniques and equipment usually beyond the scope of the home brewer.

This HBT Wiki article tells you how to determine how much slurry to pitch. The above-referenced yeast washing thread tells you how to manage your yeast.

Cheers,

Bob

* I'm not going to get into brewers who go into painstakingly minute detail over their malts and hops and then put their fresh wort into a disgustingly dirty fermenter. WTF, over?

I'm pitching a cream ale onto a 1056 yeast cake from a stout, no washing at all.
I'll let you know how it turns out.

so, how'd it turn out?

It turned out fricken amazing. Chery stout and after a few months was the best stout I ever thad.

So I've had a Scotch ale (OG 1.070) on WLP007 in the primary for 2 weeks, and I am planning to put an Imperial Stout (OG 1.092) on the yeast cake this weekend. My only real concern should be a yeast explosion, right? This is only my 5th batch and the 1st time re-using a yeast cake.