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Warm dry yeast into cold wort

A lot of brewers rehydrate dry yeast at 100 or so. What effect does that have on pitching said yeast* into a lager wort at 50 or so? Wouldn’t the temperature drop shock the yeast and cause more of a lag than simply tossing the yeast in straight from the fridge?

*S-189

Jamil has mentioned that “rehydrating” dry yeast isn’t recommended, because the yeast is ready to go out of the package, with the right amount of nutrients and cells in order to begin fermentation on a 5-gal batch of beer. Re-hydrating it past the pitching temperature (ie: up to 100 deg) wouldn’t be a good idea because fermenting at high temperatures produces off-flavors most people don’t like.

I agree with you- the shock from going from 35 deg in the fridge to 65 deg in the cooled wort would be a shock, but I’ve never had an issue with it. You may experiment with leaving the yeast on the counter, or putting the closed package into a cup of 65 deg water, then pitching it when you are ready.

[quote=“learningmore”]Jamil has mentioned that “rehydrating” dry yeast isn’t recommended, because the yeast is ready to go out of the package, with the right amount of nutrients and cells in order to begin fermentation on a 5-gal batch of beer. Re-hydrating it past the pitching temperature (ie: up to 100 deg) wouldn’t be a good idea because fermenting at high temperatures produces off-flavors most people don’t like.

I agree with you- the shock from going from 35 deg in the fridge to 65 deg in the cooled wort would be a shock, but I’ve never had an issue with it. You may experiment with leaving the yeast on the counter, or putting the closed package into a cup of 65 deg water, then pitching it when you are ready.[/quote]

Making a starter with dry yeast isn’t recommended. Rehydrating is fine, although I seldom do it and get good results anyway.

BTW, putting colder yeast into warmer wort is fine. It’s actually the best thing to do is you have a yeast starter for liquid yeast.

You won’t shock the yeast going from cold to warm.

As for rehydrating (which I do about half the time) you can acclimate the yeast by slowly adding the cooled wort to the rehydrating vessel a half cup at a time to gradually lower the temp.

If you rehydrate the yeast near 100*. Let it sit for 10 minutes or so to bloom. I bet the temp will have dropped to near room temp. I don’t see an issue.

+1, just check first

Actually I meant going from 100 rehydrate temperature going into 50 wort. It’s my understanding that going from cold to warmer isn’t a problem.

That’s what I thought.

I haven’t re-hydrated for a long time. maybe I should have a glass of water. or Michelob Ultra Light. :lol:

I’ve seen one of the dry yeast manufacturers say that you can either pitch dry or rehydrate. Both methods work. I have mostly pitched dry and it has worked great.

I did rehydrate once and it seemed like a hassle, and went against the whole RDWHAHB spirit to have to worry about having just the right temp of water (not too hot, not too cold), or adding a possible point of infection, so I elected to not use that method. Made great beer.

[quote=“twdjr1”]I’ve seen one of the dry yeast manufacturers say that you can either pitch dry or rehydrate. Both methods work. I have mostly pitched dry and it has worked great.[/quote]Rehydrating in wort instead of water reportedly kills about 50% of the yeast, so if you’re going bigger than maybe 1.060 and pitching dry, go with two packs to account for the losses. Or rehydrate and save $4.

Actually I meant going from 100 rehydrate temperature going into 50 wort. It’s my understanding that going from cold to warmer isn’t a problem.[/quote]

Correct.

A glass of water tastes better, and is cheaper.

A glass of water tastes better, and is cheaper.[/quote]

And less strain on the poor old horse. :wink:

I have never rehydrated dry yeast in my life. I think you’ll be just fine.

I rehydrate, let it bloom and then cool it to pitching temps. Not a problem to do, because I do it near the end of the boil and don’t use more than a half cup of water. For lagers, my final few degrees of cooling typically occurs in my lager chest, anyway. Even so, I don’t think you have to do it, because the number of yeast cells in a sachet of dry yeast is so great that killing off some generally still allows for a reasonable pitch - but I don’t have a cytometer, so this is merely anecdotal. I agree that with a bigger beer direct pitched, I would suggest going with a second pack.

In Yeast (the book), Jamil and Chris White note that “skipping rehydration kills about half the cells pitched.” They go on to recommend rehydrating in sterile tap water at 105 degrees F.

Check out this experiment:

http://seanterrill.com/2011/04/01/dry-yeast-viability/

In Yeast (the book), Jamil and Chris White note that “skipping rehydration kills about half the cells pitched.” They go on to recommend rehydrating in sterile tap water at 105 degrees F.

Check out this experiment:

http://seanterrill.com/2011/04/01/dry-yeast-viability/[/quote]

I too have never ever once heard JZ advise not to rehydrate. Perhaps I missed it, but I can’t see any good reason not to rehydrate. That said, I’ve done it both ways.

In Yeast (the book), Jamil and Chris White note that “skipping rehydration kills about half the cells pitched.” They go on to recommend rehydrating in sterile tap water at 105 degrees F.

Check out this experiment:

http://seanterrill.com/2011/04/01/dry-yeast-viability/[/quote]

I too have never ever once heard JZ advise not to rehydrate. Perhaps I missed it, but I can’t see any good reason not to rehydrate. That said, I’ve done it both ways.[/quote]

Believe it or not, a lot of people seem to screw up rehydration by using water that’s too hot. I know of at least one large homebrew operation that advised its customers to not rehydrate because so many of them killed the yeast by rehydrating.

[quote]

Believe it or not, a lot of people seem to screw up rehydration by using water that’s too hot. I know of at least one large homebrew operation that advised its customers to not rehydrate because so many of them killed the yeast by rehydrating.[/quote]

If they can’t get the temperature for rehydrating dry yeast right how do they manage to brew anything drinkable?

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