Rehydrated dry yeast temp

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Dolfan86

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I know I should pitch my yeast at or slightly below fermentation temp, my case it's 64 so my yeast should be at that temp too correct? The instructions for rehydrating my dry yeast calls for 85-94 degree water, is it okay to put the rehydrated dry yeast in my fermentation chamber to get down to 64 after rehydrating? If so how long is it ok to leave in the fermentation chamber before pitching? Thanks!
 

BlueHouseBrewhaus

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Rehydrate at 85 - 95F and then add doses of your cooled wort to it every 5 or 10 min to drop the temp 5-10 degrees each time until you're at pitching temp.

Or you can just pitch your rehydrated yeast into the cooled wort knowing that some of them will die of shock but plenty of their comrades will carry on just fine.

Or cool your wort to <80F, pitch your rehydrated wort directly without cooling and cool the whole mess to ferm temp over 12 hours so it has cooled before fermentation starts.

Or just pitch the yeast dry (as some dry yeast manufacturers recommend) knowing that some will die but plenty of their comrades will carry on .... yada-yada-yada.

In other words, yeast are pretty hardy little buggers and will likely do fine unless you freeze them or boil them. All that being said, the first method listed is the uber-correct way of doing it.
 

Allenk

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I agree with the post above. I saw a talk from a technical adviser from fermentis. He recommended not pitching into a wort more than 5 degrees different than the yeast. With a high gravity wort you can add a little wort to the rehydrated yeast to help it acclimate.
 
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Dolfan86

Dolfan86

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Thanks y'all. Much appreciated
 

ncbrewer

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After the standing time for rehydration, I put the rehydrated yeast in a cold water bath once or twice to let it cool about 10 degrees at a time. As per Danstar, this method also works. But they do instruct not to delay pitching for more than 30 minutes after the start of rehydration, so I add 3/4 oz of wort before starting the water baths (also per Danstar's advice).
 

mongoose33

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Hmmmmm....no RO water for rehydration?

Saturday I brewed using S-05 dry yeast. Put some RO water in a Pyrex cup, boiled it in microwave, covered with sanitized foil, waited until it cooled to room temp, added the dry yeast, let it sit for 30 minutes, stirred again (sanitized spoon), recovered, then pitched when the time was right (wort at about 76 degrees, yeast was at a similar temp).

It did take nearly 24 hours to get going at a set temp of 65 degrees (put in ferm chanber so it slowly cooled down to 65). But it's going.

I didn't recall the "don't use RO water to rehydrate" so I visited Fermentis' website to see their specific instructions for rehydration. Here they are:

Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 27°C ± 3°C (80°F ± 6°F). Leave to rest 15 to 30 minutes. Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel. Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the wort using aeration or by wort addition.

No admonition to avoid RO water. That said, next time I'll probably rehydrate in my tap water just to see if there's any difference in lag time.
 
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