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Old 01-01-2013, 05:32 PM   #31
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Man this thread had slow start but eventually got to good info. Just to reiterate, yeast rehydrate at nearly 100% viability in warm water while rehydration in a sugar dense liquid may yield 60% (IOW, 40% of the cells die).

From the Danstar FAQ:

Quote:
Why is rehydrating the dry yeast before pitching important?

Dry beer yeast needs to be reconstituted in a gentle way. During rehydration the cell membrane undergoes changes which can be lethal to yeast. In order to reconstitute the yeast as gently as possible (and minimize/avoid any damage) yeast producers developed specific rehydration procedures. Although most dry beer yeast will work if pitched directly into wort, it is recommended to follow the rehydration instructions to insure the optimum performance of the yeast.
rehydration instructions for Safalel US05
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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.
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Old 01-01-2013, 06:53 PM   #32
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Originally Posted by Bobby_M View Post
Man this thread had slow start but eventually got to good info. Just to reiterate, yeast rehydrate at nearly 100% viability in warm water while rehydration in a sugar dense liquid may yield 60% (IOW, 40% of the cells die).

From the Danstar FAQ:


rehydration instructions for Safalel US05
Good info! So as long as the wort is above 68 degrees then the yeast won't go into shock? I can see how pitching yeast from 80 degree water to below 68 degree wort can possibly shock the yeast.
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Old 01-01-2013, 09:59 PM   #33
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The rule I've seen is that you don't want more than a 10°F (5°C) jump in temperature between the yeast being pitched and the wort it's being added to. From other threads and the 71b-1122 data sheet, rehydrated yeast lose viability about 45 minutes after rehydration because they deplete the reserves that were stored with them.

Because of this, waiting for the rehydrated slurry to drop to the pitching temperature can be too slow. For some yeasts, the advice is to add small quantities of wort and mix them, wait a couple minutes, and repeat. This can bring the slurry to pitching temperature faster than waiting, but slow enough to avoid a thermal shock.

In most cases, the pitch rates are high enough with dry yeast that we're picking at details with a lot of these concerns, though. Other than major errors (like cooking the yeast), more than likely enough yeast will survive that you'll be within a factor of a few of the pitch rate you're after. I think for most of us, that's close enough that it's unlikely to be the difference between a good and a bad beer.

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Old 01-02-2013, 12:28 AM   #34
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Originally Posted by zeg View Post
The rule I've seen is that you don't want more than a 10°F (5°C) jump in temperature between the yeast being pitched and the wort it's being added to. From other threads and the 71b-1122 data sheet, rehydrated yeast lose viability about 45 minutes after rehydration because they deplete the reserves that were stored with them.

Because of this, waiting for the rehydrated slurry to drop to the pitching temperature can be too slow. For some yeasts, the advice is to add small quantities of wort and mix them, wait a couple minutes, and repeat. This can bring the slurry to pitching temperature faster than waiting, but slow enough to avoid a thermal shock.

In most cases, the pitch rates are high enough with dry yeast that we're picking at details with a lot of these concerns, though. Other than major errors (like cooking the yeast), more than likely enough yeast will survive that you'll be within a factor of a few of the pitch rate you're after. I think for most of us, that's close enough that it's unlikely to be the difference between a good and a bad beer.

Ok sounds good. I normally cool my wort to just below 80 degrees before pitching the yeast. If I hydrate the yeast in 90 degree water then it shouldn't be an issue regarding pitching temperature.
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Old 01-02-2013, 12:50 AM   #35
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Originally Posted by BansheeRider View Post
Ok sounds good. I normally cool my wort to just below 80 degrees before pitching the yeast. If I hydrate the yeast in 90 degree water then it shouldn't be an issue regarding pitching temperature.
Ive had pretty fruity beers pitching at that temp,if you like it then have at. I havent done that since my first few beers,which I think is way to high. You could get too fast a ferment as well as alot of esters. Ive always had good beers with nothing off hydrating at recommended temps then pitching at ferm temps. It does seem that you should add some wort after 15 min to ease it into your main pitch wort temp. Its really only about viability loss. So if you pitch more than enough dry yeast then you can pitch dry or hydrate and pitch the 20 degree difference and still afford some of the viability loss. Although it does stress and add loss of viability but again, if you overpitch you shouldnt have to worry too much about the temp difference. Although its better to strive for optimum yeast viability.
Also if your pitching just below 80 what temps does that mean your fermenting at? More than 10 deg drops can stress yeast(maybe more?) that way if you ferment in the mid low 60's that way. And its generally more estery fermenting above 70 to ferment in most yeast it seems anyway if your primarily fermenting that high.
So long story short: you may be getting more stressed yeast pitching @ 80 and fermenting above 70.

I dont generally hydrate- then add cooled(primary temp) wort- then pitch to main wort. I generally overpitch-hydrate, then just throw the hydrated yeast in to wort below or close to 70. If I knew I wasnt overpitching then I would add wort after hydration to get it closer to primary pitch temps.
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Old 01-02-2013, 01:01 AM   #36
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I use tepid tap water with a little table sugar mixed in.

I pour the dry yeast on top and let it sit there. I do not stir it in. I let it do its thing for a few hours.

I swirl it around and dump it into my wort when it is ready.

http://www.homebrewtalk.com/f39/ferm...tution-365182/

I don't stir it once it is in the wort.

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Old 01-02-2013, 01:13 AM   #37
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Quote:
Originally Posted by Dynachrome View Post
I use tepid tap water with a little table sugar mixed in.

I pour the dry yeast on top and let it sit there. I do not stir it in. I let it do its thing for a few hours.

I swirl it around and dump it into my wort when it is ready.

http://www.homebrewtalk.com/f39/ferm...tution-365182/

I don't stir it once it is in the wort.
You dont really want to "proof" it like bread yeast. Just hydrate it first. Shure that will work but you will get loss from that as discussed previously.
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Old 01-02-2013, 01:30 AM   #38
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Quote:
Originally Posted by jonmohno View Post
Ive had pretty fruity beers pitching at that temp,if you like it then have at. I havent done that since my first few beers,which I think is way to high. You could get too fast a ferment as well as alot of esters. Ive always had good beers with nothing off hydrating at recommended temps then pitching at ferm temps. It does seem that you should add some wort after 15 min to ease it into your main pitch wort temp. Its really only about viability loss. So if you pitch more than enough dry yeast then you can pitch dry or hydrate and pitch the 20 degree difference and still afford some of the viability loss. Although it does stress and add loss of viability but again, if you overpitch you shouldnt have to worry too much about the temp difference. Although its better to strive for optimum yeast viability.
Also if your pitching just below 80 what temps does that mean your fermenting at? More than 10 deg drops can stress yeast(maybe more?) that way if you ferment in the mid low 60's that way. And its generally more estery fermenting above 70 to ferment in most yeast it seems anyway if your primarily fermenting that high.
So long story short: you may be getting more stressed yeast pitching @ 80 and fermenting above 70.

I dont generally hydrate- then add cooled(primary temp) wort- then pitch to main wort. I generally overpitch-hydrate, then just throw the hydrated yeast in to wort below or close to 70. If I knew I wasnt overpitching then I would add wort after hydration to get it closer to primary pitch temps.
My fermenting temps fluctuate between 68-72 degrees. I have only done one batch of beer (currently in secondary carboy). I pitched the dry yeast at 80 degrees. The next morning the beer was fermenting like crazy at about 70 degrees. Are you saying this will create off flavors? I just ordered a recipe kit, I will try to get my wort to about 70 degrees this time before pitching the yeast.
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Old 01-02-2013, 01:38 AM   #39
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Quote:
Originally Posted by BansheeRider View Post
My fermenting temps fluctuate between 68-72 degrees. I have only done one batch of beer (currently in secondary carboy). I pitched the dry yeast at 80 degrees. The next morning the beer was fermenting like crazy at about 70 degrees. Are you saying this will create off flavors? I just ordered a recipe kit, I will try to get my wort to about 70 degrees this time before pitching the yeast.
It can. And depends what yeast if you want that or not. Its just something I learned and didnt know even with months of research before brewing,its just something that I didnt come across. Especially when directions say pitch below 80 deg. Yes,but generally that is still to high. JUst give your beer longer and it could still and may turn out very good right away, if its not give it more time and it may get better. There are alot of other things that can account for many different characters that may even be misleading at first when starting out. I was a little frustrated at first and just thought that homebrew may not be good or something.It was only a few things I happed to overlook which took experience and time to figure out.
Is your actuall beer 70 deg or your ambient temps 70? If you feel your fermenter and its pretty warm then you may have somewhat an estery beer.
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Old 01-02-2013, 02:03 AM   #40
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For my first few batches, I pitched in the low 80s or high 70s simply because I didn't yet have a good way to cool the wort and I got tired of waiting. I've not had what I'd call any fruity off flavors. In my case, I used Nottingham dry yeast, pitching two 11g packets. That should be a pretty generous pitch, although it's in line with the recommended numbers that were either on the packet or on the datasheet. That's a yeast that, especially at fermentation temps in the low 60s, tends to be pretty clean. So it's possible I did get some esters but the rest of the fermentation was so clean that they weren't enough to be prominent.

Now that I've got an immersion chiller, I can get down to proper ale temperatures very quickly. For lagers, I just chill it to room temperature, then stick it in the fridge overnight and pitch the next evening in the upper 40s.

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