Using yeast after a high gravity DIPA

[eluterio]

I am currently using wlp001 for a low gravity beer OG 1.032. Made a 1 ml starter for it with a gravity of 1.044 pitched that in 5 gallons. Plan was to make this and use it as a starter for a DIPA with a OG of 1.070-1.075. I was just going to drain my wort right onto the yeast cake.

Question, will the yeast be strained from the high gravity to wash and reuse?

 

[fatnoah]

I am guessing you meant you made a 1L starter?

Is your question about reusing the yeast after the DIPA? If so I would be hesitant to wash and reuse yeast that has just fermented a DIPA. There is going to be a LOT of hop residue in there and the yeasties are going to be pretty tuckered out. I think you'd be safer saving some of the yeast from this low gravity starter beer and building it up with a starter.

 

[eluterio]

Correct on the starter and yeah that's what I was thinking. I think I'll just dump after DIPA since I don't have time to wash yeast tomorrow.

Thanks


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[kanzimonson]

I wouldn't reuse the DIPA yeast - too much bitter resins coating the yeasties, and a little high on the alcohol to believe that they are the healthiest post fermentation.

I also wouldn't pitch the whole DIPA on the yeast cake. Using somewhere around 1/3 to 1/2 of the yeast cake will be about the right pitch rate. Just about the only time you'd want to pitch onto an entire yeast cake is if you're making a MEGA barleywine... something like 1.110+. Even then it's questionable.

How about saving the other portion of the yeast cake you don't use for a future batch? If you haven't done any yeast rinsing yet, you can just treat this as an experiment to learn the process. If you end up lacking confidence in the final product, dump it and forget it.

 

[eluterio]

It's the prep time that I didn't really have to rinse the yeast and use x amount but it sounds like my day just got a bit longer. What you said makes sense not using the entire yeast cake only a portion. If I'm going to use only a portion then I might as well save me some for future batches.

Question now I as how much ML do I use for the big DIPA? I figure I'll just pull off a slurry of yeast then rinse the rest. Thoughts?


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[kanzimonson]

Yeah, you don't want to overpitch it - commercial breweries are targeting a certain pitch rate, yielding a certain growth rate, all for a certain flavor profile. I believe that all homebrewers should do their best to mimic commercial breweries.

So again, if you're not comfortable with the washing procedure then this is a good opportunity to test it out and not be worried about the consequences.

If you really don't have the time, then here's my next best recommendation: When I rack a beer out of a primary fermenter and leave behind the slurry, I have found that there's about a quart of stuff in there. So you should get several pint mason jars (or something else where you can estimate volume), they don't need to be clean. Rack your beer out of the primary to wherever it's going. Then pour the remaining sludge into your measuring jars/cups until you've poured out about 2/3 of a quart. Then rack your DIPA onto the remaining slurry.

It's not the most accurate, but I still feel this is better than pitching onto a whole cake. Assuming this primary hasn't been sitting around for weeks, the yeast are probably pretty viable. You may want to add some yeast nutrients to the DIPA wort.

 

[Calder]

During reproduction, yeast will reproduce to about 6x the recommended pitching rate. So if you cold crash a beer after the first 24 hours, you would have enough yeast to straight pitch 6 batches of the same volume and gavity.

During fermentation, and conditioning, many cells will die, but the majority of the population will remain healthy.

To account for the lost cells, I generally assume I have 4x healthy cells when I rack off the cake. Based on this assumption, I would use a quarter of a cake for a beer if the same volume and gravity. In your case, the gravity is ~2x, so you would need 2x the yeast, or about half the cake.

While it is not good prctice to reuse yeast from high gravity batches, the occasional re-use will not be a problem. Provided you only use 'enough' of the high geavity cake, the yeast will reproduce with healthy cells, and ferment fine. Continual re-use of yeast from high graviy beers will accelerate mutation of the yeast.

 

[eluterio]

So just decanted and shook up and filled two pint jars. I figure I should get enough yeast out of these roughly looking like the yeast cake Is about 300ml each.


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