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-   -   Hot Fermentation - Yeast Worth Harvesting? (http://www.homebrewtalk.com/f163/hot-fermentation-yeast-worth-harvesting-289025/)

Xaphoeous 12-23-2011 03:47 PM

Hot Fermentation - Yeast Worth Harvesting?
 
Hey guys, I have two batches of yeast from two different brews that both fermented pretty warm. One reached 84 on the Fermometer strip on the carboy, the other reached 79 on the Fermometer strip on a plastic bucket. I am already aware that I need to keep them cooler than that, but a ductwork problem in the basement caused the temp down there to reach abnormaly high temps, allowing the beer to get very warm.

I had planned to harvest both of these yeast cakes, but both batches of beer are a little sour/tart tasting right now as I bottle them. Are the yeast probably overworked and should be thrown out, or are they still good to harvest and use on other beers?

One was a porter (OG 1.057, FG 1.014), one was a stout (OG 1.052, FG 1.009). Both are Nottingham.

Thanks for the help!

JohnnyO 12-23-2011 03:59 PM

X, I would start anew. I am no expert on the subject, but I would venture to guess that your yeast have been stressed by the heat. Spend the $6 for a new vial of yeast next brew.

giligson 12-23-2011 04:03 PM

You can "re culture" the yeast if you wish - ie build up a new cake from a small sample, this time in ideal conditions. But, don't use the current cake unless you want the next beer to taste like the current one.

Xaphoeous 12-23-2011 04:06 PM

Thank you. I think I will probably just end up scrapping these two and starting fresh with a new vial.

Thanks for the input!

bad coffee 12-23-2011 06:07 PM

IF it's the old-old-old Notty, I'd try it. If it's the new stuff, just buy a new packet your next brew.

If you're going to make a starter, take a couple of vials before you pitch. That way you've got a fresh base to fall back on if your fermentation goes funky again.

Harvesting after the beer is done you'll get somewhat better yeast. Jamil says his yeast is best around 4-5 generations. YMMV

B

Randar 12-24-2011 12:19 AM

Quote:

Originally Posted by Xaphoeous (Post 3596186)
Hey guys, I have two batches of yeast from two different brews that both fermented pretty warm. One reached 84 on the Fermometer strip on the carboy, the other reached 79 on the Fermometer strip on a plastic bucket. I am already aware that I need to keep them cooler than that, but a ductwork problem in the basement caused the temp down there to reach abnormaly high temps, allowing the beer to get very warm.

I had planned to harvest both of these yeast cakes, but both batches of beer are a little sour/tart tasting right now as I bottle them. Are the yeast probably overworked and should be thrown out, or are they still good to harvest and use on other beers?

One was a porter (OG 1.057, FG 1.014), one was a stout (OG 1.052, FG 1.009). Both are Nottingham.

Thanks for the help!

If you are getting off flavors on the original cultures, you need to start over. If not and you are simply worried about stress, you can grow them up from a lower gravity starter with plenty of nutrient and oxygen at the start (or a stirplate)...


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