Author Topic: Rehydrating Dry Yeast  (Read 6042 times)

Offline blatz

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Re: Rehydrating Dry Yeast
« Reply #15 on: October 16, 2012, 08:25:55 AM »
unopened 1/2 liter bottle of distilled or RO water (should be sanitary so long as it is sealed), let warm in the sun, the dump half, add yeast, swirl, voila.

most of the time, I'm too lazy to do it and just sprinkle and add another pack...
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Offline erockrph

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Re: Rehydrating Dry Yeast
« Reply #16 on: October 16, 2012, 08:29:59 AM »
unopened 1/2 liter bottle of distilled or RO water (should be sanitary so long as it is sealed), let warm in the sun, the dump half, add yeast, swirl, voila.

most of the time, I'm too lazy to do it and just sprinkle and add another pack...

Interesting. I think I've always heard from the rehydration camp that you shouldn't use RO/distilled water because the yeast want some minerals in their rehydration water.
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Re: Rehydrating Dry Yeast
« Reply #17 on: October 16, 2012, 08:30:19 AM »
Regarding the source of water for rehydrating yeast, I used to boil the water first but now I used municipal water that has passed through a carbon monobloc filter reasoning that it was very unlikely to contain significant quantities of beer spoilers.  Is my reasoning correct?  I don't repitch my yeast.

yes, that should be reasonably safe. Even for repitching yeast. You'll pick up more contamination from brewing than from the water.

If you want to test it, tough, you could do this:

take two glass jars, that you boiled to sanitize them, and fill them with some of your brewed and cooled wort. Then add some tap water to one of them and mark it. Cover with a lid or aluminum foil. Don't close he lid tightly. Let this at a warm spot until it starts fermenting. You are basically doing a wort stability test on the water. If the watered sample turns noticeably earlier, you have a contamination in the water and should refrain from adding it to your beer un-boiled.

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Offline blatz

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Re: Rehydrating Dry Yeast
« Reply #18 on: October 16, 2012, 08:31:10 AM »
unopened 1/2 liter bottle of distilled or RO water (should be sanitary so long as it is sealed), let warm in the sun, the dump half, add yeast, swirl, voila.

most of the time, I'm too lazy to do it and just sprinkle and add another pack...

Interesting. I think I've always heard from the rehydration camp that you shouldn't use RO/distilled water because the yeast want some minerals in their rehydration water.

that's true.  I've heard that as well.  guess you could use spring water instead - I generally have used whatever we had in the outside fridge - sometimes spring, sometimes distilled/dasani
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Offline nateo

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Re: Rehydrating Dry Yeast
« Reply #19 on: October 16, 2012, 08:35:30 AM »
I use 10ml per gram tap water in mason jar, microwave for 2-3 minutes, then let cool to 105-110* or so, then add yeast. The cold yeast usually drops the water temp 5* or so. I use go-ferm more often than not, so if you're using something like that, distilled water would be fine. Otherwise, diffusion will suck all the goodies out of the yeast bags.
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Re: Rehydrating Dry Yeast
« Reply #20 on: October 16, 2012, 01:25:13 PM »
Regarding the source of water for rehydrating yeast, I used to boil the water first but now I used municipal water that has passed through a carbon monobloc filter reasoning that it was very unlikely to contain significant quantities of beer spoilers.  Is my reasoning correct?  I don't repitch my yeast.

I would use the unfiltered water, personally. The carbon is filter is just another opportunity for contaminants to be introduced.
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Offline firedog23

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Re: Rehydrating Dry Yeast
« Reply #21 on: October 16, 2012, 01:45:17 PM »
I just used Fermentis T58 and did not hydrate and quite honestly, I don't know if it would have started any faster or needed to hydrate.  I have had great luck with US-05 but this stuff was a monster.  It raced to full fermentation in 6 hours and the next morning it was around 78 degrees which made me move quick to cool it down as I did not see the big temps coming.  It has since been cooled to the mid-60's but it is still bubbling away.
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Re: Rehydrating Dry Yeast
« Reply #22 on: October 16, 2012, 03:05:42 PM »
Regarding the source of water for rehydrating yeast, I used to boil the water first but now I used municipal water that has passed through a carbon monobloc filter reasoning that it was very unlikely to contain significant quantities of beer spoilers.  Is my reasoning correct?  I don't repitch my yeast.

I would use the unfiltered water, personally. The carbon is filter is just another opportunity for contaminants to be introduced.

The carbon filter removes chlorine which is a minor plus from avoiding chlorophenolics.  The monobloc also removes bacteria, but I couldn't say down to what size. 
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Offline tschmidlin

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Re: Rehydrating Dry Yeast
« Reply #23 on: October 19, 2012, 11:55:40 PM »
Another thing about temperatures that concerns me is that 100 degrees is a lethal temperature for a lot of yeast strains so rehydrating in that is just scary to me. But who knows, maybe it is better.
I think it would be fine - I typically rehydrate at 100-105F without issues.  The water doesn't stay that warm for that long.  There are yeast assays that call for 108F for 15 minutes, and the yeast survive that just fine so I doubt 105F and dropping over time is going to cause problems (and it hasn't for me).
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Offline dimik

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Re: Rehydrating Dry Yeast
« Reply #24 on: October 21, 2012, 09:39:49 PM »
Actually it seems to have worked very well.
It bubbled like MAD at 54 for about 2 days in just a couple hours after pitching (was too busy to look at the temperature so ended up with an English "lager" Winter Warmer lol). After that I moved it to my room and it bubbled for one more day and stopped. Not going to even look at it for a few more weeks, but it seems to me like it was the strongest dry yeast induced fermentation I've ever experienced.
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Offline anje

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Re: Rehydrating Dry Yeast
« Reply #25 on: November 06, 2012, 02:18:17 PM »
Well, I tried it this time. Rehydrated a pack of US-05 in the Fermentis-recommended 80F water for a while (I know, sounds cool to me too, but I decided to do it their way for a first try), then pitched it. Next morning, the airlock was burbling happily. Usually, I spend the day after brewing anxiety-ridden because I didn't seem much yeast activity before leaving for school.

There's more than one thing changed with this batch vs the previous APA I did, so I don't know what I'll be able to attribute specifically to the rehydrated pitch. (Need to try new things vs need to control experiments -- Argh!) But the peace of mind at seeing such obvious fermentation alone is reason to keep doing it.
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Offline Pinski

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Re: Rehydrating Dry Yeast
« Reply #26 on: February 08, 2013, 08:49:14 AM »
So, If I'm planning on boiling my water that I'll use to rehydrate some US-05 is there any reason I shouldn't add enough DME to the equivalent concentration of a typical starter  and a pinch of yeast nutrient for the purpose of rehydrating? I'm wondering if this would provide a nice boost or if the yeast would be confused by spending a short time in a "starter" solution prior to being pitched (say, after a couple hours or so).
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Offline morticaixavier

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Re: Rehydrating Dry Yeast
« Reply #27 on: February 08, 2013, 09:34:36 AM »
So, If I'm planning on boiling my water that I'll use to rehydrate some US-05 is there any reason I shouldn't add enough DME to the equivalent concentration of a typical starter  and a pinch of yeast nutrient for the purpose of rehydrating? I'm wondering if this would provide a nice boost or if the yeast would be confused by spending a short time in a "starter" solution prior to being pitched (say, after a couple hours or so).

As I understand it this is a bad idea because the yeast, when first reintroduced to a liquid environment are not prepared to triage what goes in to the cells via dried out membranes. So they can not regulate how much and and what kind of things are coming in and this causes a lot of damage if there are lots of sugar and other stuff in the liquid. Plain water gives them a chance to wake up and get their membranes working properly before they have to deal with sugars and other chemicals.

They already have the reserves they need to get through this period well. Hence the manufacturers recommending rehydration in plain water.
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Offline Pinski

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Re: Rehydrating Dry Yeast
« Reply #28 on: February 08, 2013, 09:48:04 AM »
So, If I'm planning on boiling my water that I'll use to rehydrate some US-05 is there any reason I shouldn't add enough DME to the equivalent concentration of a typical starter  and a pinch of yeast nutrient for the purpose of rehydrating? I'm wondering if this would provide a nice boost or if the yeast would be confused by spending a short time in a "starter" solution prior to being pitched (say, after a couple hours or so).

As I understand it this is a bad idea because the yeast, when first reintroduced to a liquid environment are not prepared to triage what goes in to the cells via dried out membranes. So they can not regulate how much and and what kind of things are coming in and this causes a lot of damage if there are lots of sugar and other stuff in the liquid. Plain water gives them a chance to wake up and get their membranes working properly before they have to deal with sugars and other chemicals.

They already have the reserves they need to get through this period well. Hence the manufacturers recommending rehydration in plain water.

That makes really good sense.  I suppose I should have just asked myself what I would prefer if I were dehydrated. Thanks Mort.
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Offline BrewQwest

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Re: Rehydrating Dry Yeast
« Reply #29 on: February 12, 2013, 02:42:38 PM »
Tried something new, for me anyways.... took some go-ferm rehydration nutrient at the proper dosage and added that to the cooled boiled water...then added the S-189 lager yeast packets to that....waited 15 min....slightly stirred (became really frothy) and pitched it into the fermentor at 50F .... bubbling merrily away within 8 hours.... cheers!!
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