Recycle yeast cake?

Hi,

about four days ago I began fermenting beer using either Wyeast's Roselare or Lambic Blend. I will be leaving home for 4 months in five days time.

-Is it better to rack @ day 7 or 8 of primary fermentation, or would it be okay to leave the beer in the primary fermentor for 4 months?

-If it is better to rack ~ day 7, will the yeast cake still be suitable for a second generation of beer? I would like to rack new wort onto the yeast cakes.

-Would it be okay to leave the second generation of beer (unhopped) in primary for four months? Or would this be too long to sit on the yeast cake?

Both fermentations are going strong at day 4 and sediment has formed.

If you do rack it, you must wash the yeast. No way you can use that yeast cake after so long if you leave it to sit.

CTR08 said:

If you do rack it, you must wash the yeast. No way you can use that yeast cake after so long if you leave it to sit.

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maybe you don't understand...

I am thinking about racking to secondary after 7 days in primary fermentor, and then immediately racking a new batch of wort onto the week-old yeast cake.

Yeah that's fine. you might want to dump some of the cake to avoid too high of a pitch rate

But yeah the yeast will be just dandy.

Any other opinions on this matter?

note that the first generation of beer was 36 IBUs...I'm thinking maybe I should add some lactobacillus, or will it grow from the original yeast cake, despite the high IBUs of the first beer?

Absolutely leave it on the cake for at least a few months. You can reuse it another generation, just rack a new beer onto the cake

If you want a funkier beer leave it on the cake, if not don't rack it and put a new beer on the cake. You can rack a second beer on the cake even after several months. I would add some new yeast though.

Do it. This way you have two beers with different profiles when you come back. If the starting beers are otherwise identical then I wouldn't do anything to the cake but rack right onto it with the second. This will give you a great way to see for yourself the difference between a beer that was racked to secondary and one that wasn't--I want to hear the details. Then you will have an idea what you want to do with the third one you rack onto the cake--if you choose to do it.

Delaney said:

maybe you don't understand...

I am thinking about racking to secondary after 7 days in primary fermentor, and then immediately racking a new batch of wort onto the week-old yeast cake.

Click to expand...

Sours like to stay on the cake. the Brett feeds off the dead sacc.

I would suggest racking the beer, and then swirling up the cake to a slurry, and adding about half of it to the original beer and racking the new beer onto the other half. That way both get some of the cake, both get lots of bugs.

The beers will do fine sitting on the cake. The Brett counteracts the autolysis effect by feeding off the dead yeast.

Delaney said:

note that the first generation of beer was 36 IBUs...I'm thinking maybe I should add some lactobacillus, or will it grow from the original yeast cake, despite the high IBUs of the first beer?

Click to expand...

Both Lacto and Pedio will not propagate (and therefore will not create lactic acid) in worts with high IBUs. I think 36 is way too high for anything you might have. I don't think it kills it, it just doesn't propagate. Adding more lacto will not change the IBUs, so will be pointless. I don't know what the practical threshold is, but there is a reason they say to limit the IBUs in Sours to 10.

I'd suggest trying to add the dregs from a couple of bottles of JP beers. They have a couple that have decent IBUs and seem to sour OK. I think any JP beers will do, I believe all their barrels have the same bugs.

I'm sure the commercial brewing strains can work in low IBU worts, but when making a Berliner Weisse, I found the Lacto I was using to sour the wort (Acidophilus) will not work if there are any hops in the wort.