Yeast Cake Generations?

cannondale · Post by **cannondale** » Mon Jun 21, 2010 12:50 pm

Has anyone pitched onto the same yeast cake more than once? Any thoughts or issues with this idea?

Here's what I am thinking about. I brewed an IPA (OG ~1.053) on June 14 with 1 pack of US-05. On June 20 I pitched a DIPA (OG ~1.093) right onto the yeast cake from the IPA. Next weekend, I would like to brew a RIS (OG ~1.110) and pitch it directly onto the yeast cake left by the DIPA.

Is this crazy talk?

matt7215 · Post by **matt7215** » Mon Jun 21, 2010 1:13 pm

its not crazy talk at all. do you know how to rinse the cake? you want to avoid pitching all the trub from your IIPA but if you rinse that then you will be fine.

here is one way to do it, process from notlob of ratebeer:

"I’ve found that the best way to get a good rinse is to do two transfers. First I boil up a large flask with about half a liter to a liter of water and let it cool covered with tinfoil. This is to sterilize the flask and the extra water helps me leave more of the trub behind during the second transfer. After either transferring the beer to the bottling bucket or to a keg, I give the remainder a good swirl and let it sit for a bit to let the trub/dead yeast/any hops settle. This is then decanted into the flask, which is given a swirl and let sit again for a bit to let anything unwanted settle. The liquid is finally transfered a second time into a sanitized flask, jug or a few smaller containers. I get very uniform light beige yeast each time."

markaberrant · Post by **markaberrant** » Mon Jun 21, 2010 2:28 pm

I only repitch 1-2 cups of slurry, and I would not reuse yeast from a 1.093 beer.

JerCraigs · Post by **JerCraigs** » Mon Jun 21, 2010 10:08 pm

markaberrant wrote:I only repitch 1-2 cups of slurry, and I would not reuse yeast from a 1.093 beer.

Base on what?

markaberrant · Post by **markaberrant** » Tue Jun 22, 2010 10:48 am

JerCraigs wrote:
markaberrant wrote:I only repitch 1-2 cups of slurry, and I would not reuse yeast from a 1.093 beer.
Base on what?

1-2 cups of slurry is more than enough yeast to repitch. Using the whole cake is overpitching unless you are brewing a ridiculously high gravity beer (say >1.120), plus you're also pitching onto all the trub and crap from the previous batch, so you're greatly increasing the chance of off flavours. Check out mrmalty.com for pitching rate recommendations.

Reusing yeast from a 1.093 beer is not a good idea. The stress on the yeast of a high gravity wort and higher alcohol levels will not leave you with a healthy culture for repitching.

matt7215 · Post by **matt7215** » Tue Jun 22, 2010 1:01 pm

also i think its worth saying that sa-05 is cheaper then most other yeast options. it might be worth it to just pitch a few packs rather then risk off flavours in a batch your already spending a lot on.

markaberrant · Post by **markaberrant** » Tue Jun 22, 2010 1:48 pm

matt7215 wrote:also i think its worth saying that sa-05 is cheaper then most other yeast options. it might be worth it to just pitch a few packs rather then risk off flavours in a batch your already spending a lot on.

Exactly. I have used S-05 almost exclusively for the last 2 years, and I think I've only ever repitched it once.

JerCraigs · Post by **JerCraigs** » Tue Jun 22, 2010 10:15 pm

markaberrant wrote: Reusing yeast from a 1.093 beer is not a good idea. The stress on the yeast of a high gravity wort and higher alcohol levels will not leave you with a healthy culture for repitching.

I assumed this was why. Makes sense.

cannondale · Post by **cannondale** » Wed Jun 23, 2010 12:08 pm

At $2.50 a pack for US-05, why push my luck I suppose. Clearly using the yeast cake again may turn out a perfectly fine beer. But in reviewing the available literature around yeast stress response and the like, the concerns are certainly real.