Author Topic: rehydrating dry yeast  (Read 824 times)

Offline jtoots

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rehydrating dry yeast
« on: January 21, 2015, 02:06:35 PM »
i've got a bit of an experiment going... this is one of the first times i've used dry yeast.  i did a 9 gallon batch of rye ipa, split between two carboys.  one carboy i rehydrated the yeast with 110 mL of 100 degree water, the other i simply dropped the US-05 into the carboy.  i pitched at about 17 degrees C, now we're up to 20.  we're a couple days into fermentation now.  surprisingly enough it looked like the sprinkled carboy was off to a better start, however this morning the krausen on the rehydrated carboy looked much stronger. 

what are your thoughts on dry yeast management?  i've recently read conflicting experiences with the hydrate/sprinkle debate on this forum, what are yours?

Offline erockrph

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Re: rehydrating dry yeast
« Reply #1 on: January 22, 2015, 02:12:39 AM »
In the end, the only thing that matters is the quality of your beer. I applaud you for trying this out for yourself.

Personally, for the beers I use dry yeast in, sprinkling works just fine for me with no rehydration. But this is typically for 3 gallon batches in the 1.045-1.060 range, YMMV.
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Offline jtoots

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Re: rehydrating dry yeast
« Reply #2 on: January 22, 2015, 12:48:27 PM »
In the end, the only thing that matters is the quality of your beer.

Agreed good sir.

No updates at this point, rehydrated carboy has a couple inches of krausen and the sprinkled has about an inch.  Both bubbling away.  Now is about the time with liquid yeast I'd be expecting krausen to take off and blowoff tubes would be needed.  We'll see if this batch gets that feisty.

Thanks for your input!

Offline Joe Sr.

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Re: rehydrating dry yeast
« Reply #3 on: January 22, 2015, 04:07:10 PM »
Rehydrating is so simple I just go ahead and do it.

I don't think it really has any significant impact, however.

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Offline jtoots

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Re: rehydrating dry yeast
« Reply #4 on: January 28, 2015, 02:36:39 PM »
results are in... with a goal of FG=1.016, rehydrated came in at 1.018 and sprinkled came in at 1.020. 

Offline Wort-H.O.G.

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Re: rehydrating dry yeast
« Reply #5 on: January 28, 2015, 02:41:22 PM »
results are in... with a goal of FG=1.016, rehydrated came in at 1.018 and sprinkled came in at 1.020.

FWIW, I've had beer finish on target with both rehydrated and not; not sure we can say either way is the reason for missing or hitting target FG.
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Offline jtoots

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Re: rehydrating dry yeast
« Reply #6 on: January 28, 2015, 04:08:43 PM »
results are in... with a goal of FG=1.016, rehydrated came in at 1.018 and sprinkled came in at 1.020.

FWIW, I've had beer finish on target with both rehydrated and not; not sure we can say either way is the reason for missing or hitting target FG.

Indeed... one data point here.  It's enough for me to rehydrate from this point forward though.

Offline denny

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Re: rehydrating dry yeast
« Reply #7 on: January 28, 2015, 04:38:52 PM »
results are in... with a goal of FG=1.016, rehydrated came in at 1.018 and sprinkled came in at 1.020.

Within the margin of error for measurement.  Unless these results can be repeated several times by different people, I'll take it as saying there's no difference.
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Offline TMX

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Re: rehydrating dry yeast
« Reply #8 on: January 28, 2015, 07:00:35 PM »
I usually pitch 3 packs of US05 in my 10 gallon batch. For me, my beer, and my process I get faster starts when I rehydrate and for me that gives me some piece of mind. Besides it is pretty easy to put 300ml of warm water in my 1 liter flask when I add the Irish moss
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Offline Steve Ruch

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Re: rehydrating dry yeast
« Reply #9 on: January 28, 2015, 10:45:12 PM »
Personally, for the beers I use dry yeast in, sprinkling works just fine for me with no rehydration. But this is typically for 3 gallon batches in the 1.045-1.060 range, YMMV.

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Offline Guenther

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Re: rehydrating dry yeast
« Reply #10 on: January 29, 2015, 06:02:50 PM »
Here in Brazil we use dry yeast a lot more than liquid 'cause usually it's tough to import liquid yeast from US, so when some BrewShops get some, they sell pretty fast.

Chris White and Jamil on Yeast book say that you can kill a lot of cells (book says up to 50%) if you do not re-hydrate with water because on the first moments yeast cannot regulate its cell wall permeability, so besides osmosis shock they say things like hop acids and other stuff might get in the cell and kill it.

While researching about this subject I found a very nice experiment from a Homebrewer: http://www.youtube.com/watch?feature=player_embedded&v=vOrfmzpDmPk

Basically, he splits the same wort in 4 different fermentors and he compares the same dry yeast with and without re-hydrating them using wort without aeration, and then the same thing aerating the wort with pure O².

The result is that lag-time on re-hydrated yeast was much shorter, and O² aeration pretty much didn't make any difference, which corroborates to some theories about high reservers of sterols and fatty acids dry yeast has due they condition the yeast before lyophilization (cooling the yeast gently slowly, trehalose, etc), which (in theory) makes aeration not so much important for regular OG worts (1050) with the proper amount of re-hydrated dry yeast.

On my batches, I observe exactly the same behavior as the experiment.

Regards,

Guenther
« Last Edit: January 29, 2015, 06:04:21 PM by Guenther »
Guenther Sehn

Offline TMX

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Re: rehydrating dry yeast
« Reply #11 on: January 29, 2015, 09:13:02 PM »
Here in Brazil we use dry yeast a lot more than liquid 'cause usually it's tough to import liquid yeast from US, so when some BrewShops get some, they sell pretty fast.

Chris White and Jamil on Yeast book say that you can kill a lot of cells (book says up to 50%) if you do not re-hydrate with water because on the first moments yeast cannot regulate its cell wall permeability, so besides osmosis shock they say things like hop acids and other stuff might get in the cell and kill it.

While researching about this subject I found a very nice experiment from a Homebrewer: http://www.youtube.com/watch?feature=player_embedded&v=vOrfmzpDmPk

Basically, he splits the same wort in 4 different fermentors and he compares the same dry yeast with and without re-hydrating them using wort without aeration, and then the same thing aerating the wort with pure O².

The result is that lag-time on re-hydrated yeast was much shorter, and O² aeration pretty much didn't make any difference, which corroborates to some theories about high reservers of sterols and fatty acids dry yeast has due they condition the yeast before lyophilization (cooling the yeast gently slowly, trehalose, etc), which (in theory) makes aeration not so much important for regular OG worts (1050) with the proper amount of re-hydrated dry yeast.

On my batches, I observe exactly the same behavior as the experiment.

Regards,

Guenther

Nice post, and goes with my real world experience as well.
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Offline Black Sands Brewery & Supply

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Re: rehydrating dry yeast
« Reply #12 on: February 01, 2015, 02:06:52 AM »
Here in Brazil we use dry yeast a lot more than liquid 'cause usually it's tough to import liquid yeast from US, so when some BrewShops get some, they sell pretty fast.

Chris White and Jamil on Yeast book say that you can kill a lot of cells (book says up to 50%) if you do not re-hydrate with water because on the first moments yeast cannot regulate its cell wall permeability, so besides osmosis shock they say things like hop acids and other stuff might get in the cell and kill it.

While researching about this subject I found a very nice experiment from a Homebrewer: http://www.youtube.com/watch?feature=player_embedded&v=vOrfmzpDmPk

Basically, he splits the same wort in 4 different fermentors and he compares the same dry yeast with and without re-hydrating them using wort without aeration, and then the same thing aerating the wort with pure O².

The result is that lag-time on re-hydrated yeast was much shorter, and O² aeration pretty much didn't make any difference, which corroborates to some theories about high reservers of sterols and fatty acids dry yeast has due they condition the yeast before lyophilization (cooling the yeast gently slowly, trehalose, etc), which (in theory) makes aeration not so much important for regular OG worts (1050) with the proper amount of re-hydrated dry yeast.

On my batches, I observe exactly the same behavior as the experiment.

Regards,

Guenther

Nice post, and goes with my real world experience as well.

Take away is... Nothing bad can come from rehydrating? We do it when using dry yeast.
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