Should I harvest the entire yeast cake?

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Washington_Brewologist

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Sorry if this is a dumb question. I've just kegged an IPA that has been sitting in the primary for 2 1/2 weeks and I'd like to try and save some money by harvesting the yeast. At the moment I've got about 1 or 2 inches of green beer sitting on top of about 5 fingers worth of trub in a 6-gallon carboy.

Do I need the entire yeast cake to ensure I have enough cells to repitch or can I just pour off 1 or 2 mason jars full from the fermenter and make a starter for the next batch?

Also. Is it worth harvesting yeast that you don't plan on using frequently? I've never used this particular strain before and thought it might be cool to have some stored away. I have another beer about a week into fermentation and that one was brewed using Wyeast 1056 which I use more than any other. My gut tells me I should hold off on harvesting this slurry and just wait to harvest the 1056. Let me know what you guys think...
 

ba-brewer

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If the previous batch was a higher gravity IPA with some dry hopping that is not the best yeast to reuse.

In general a full yeast cake is enough to make 3 or 4 new batches of beer. If you save with some of that left beer it will still be good for a few weeks to a month used as is. If you go longer than that it is best to make a starter from some of the slurry to revitalize the yeast.

I use mrmalty.com to figure out how much slurry to use, it is a bit conservative as far a viability but it has given me good results.

I used to over build my starters and save a portion to build up later, I had good luck waking up slurry older than 6months. That approach is better for saving less frequent used yeast than saving slurry from a batch.
 
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Washington_Brewologist

Washington_Brewologist

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If the previous batch was a higher gravity IPA with some dry hopping that is not the best yeast to reuse.

In general a full yeast cake is enough to make 3 or 4 new batches of beer. If you save with some of that left beer it will still be good for a few weeks to a month used as is. If you go longer than that it is best to make a starter from some of the slurry to revitalize the yeast.

I use mrmalty.com to figure out how much slurry to use, it is a bit conservative as far a viability but it has given me good results.

I used to over build my starters and save a portion to build up later, I had good luck waking up slurry older than 6months. That approach is better for saving less frequent used yeast than saving slurry from a batch.
Yeah, the IPA in question had 1 ounces of centennial and one ounce of cascade dry hopping for 14 days. It seems a bit greener than usual so I think I just toss it. For the next batch with the 1056, do you suggest harvesting the entire cake? I plan on making starters with the harvested yeast regardless of how long they've been stored so do I really need to fill 5 or more mason jars?
 

ba-brewer

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If you plan to build a starter from the slurry then you don't need to harvest the whole cake, one pint jar would be more than enough. If you dump lots of kettle trub into the fermentor maybe collect a second jar or over build the next starter and save a portion to use as seed. Make sure to have some beer to cover the yeast.
 
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