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Re-hydrating Yeast Temperature Question

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Guysmiley54

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Hello all,

I like to re-hydrate my yeast before pitching for optimal health but have been thinking about the best way to do it.

I currently stick to the Fermentis instructions:

Re-hydrate the dry yeast into yeast cream in a stirred vessel prior to pitching. Sprinkle the dry yeast in 10 times its own weight of sterile water or wort at 27C 3C. Once the expected weight of dry yeast is reconstituted into cream by this method (this takes about 15 to 30 minutes), maintain a gentle stirring for another 30 minutes. Then pitch the resultant cream into the fermentation vessel.
To achieve the correct temperature, ahead of time I boil some water and pour it into a sanitized glass jar to cool down overnight. When I need to have sterile (as best as I can manage anyway) water around 27C I add boiling water to increase the temperature. I know that my fridge is 3-4C and I know that boiling water is 99C so I use an online calculator to help me work out how much of each liquid will bring me to correct temp. I could use a thermometer but I prefer not to as the less I muck about the better I feel about the water staying sanitary.

I pull the yeast out of the fridge about an hour before re-hydrating to minimize temperature shock....

My question (finally!!) wouldn't it be better to re-hydrate the yeast at fridge temperature with the water at fridge temperature and then bring them to room temperature together? Surely this would be the best (and easiest!!) way to do it in regards to minimizing temperature shock.

It is possible that there is another reason why 27C is recommended, but I couldn't tell you!

What do you guys do?
 

Steve@PMF82

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I rehydrate according to the manufacturers instructions.
The procedure / temps can vary for different yeasts / brands so i encourage anyone to look up the particular yeast you have.

When my yeast is fully rehydrated i like to adjust the temp of the slurry over 10mins with 3 additions of wort then add to the fermenter and aerate with a slotted spoon.

Have been getting healthy quick ferments with good attenuation. Good for pumping out quick tasty beers to share about.

Edit: oh yeah as for temp, i boil and add to wide glass bowl cover with foil. I have a SS probe that i check the temp with. I wipe down with 70% Iso pad (you can get boxes of 100 for first aid kits)
 

Thefatdoghead

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I just boil the needed water in my erlenmeyer flask then cool it to temp specified on packet. If im feeling paranoid I sanitise a glass thermometer and check the temp of the water then pitch the yeast in. I don't usually bother sanitising the thermo but thats up to you.
 

Nick JD

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I just bung it in some cold tap water, give it a stir and wait till it's creamy/foamy.

Used to make my beer out of 95% tap water and didn't get infections, and still often diluting wort with tapwater - so not too worried about using it for rehydrating yeast.
 

Guysmiley54

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Sounds like we are all following manufacturers instructions well and getting good results. I just think it would be cleaner and easier to re-hydrate cold. I'd love to see if anyone else has experimented or has some sciencey explanation as to why it's a bad idea.

Cheers

edit: Except Nick ;) Do you find that cold water is an issue for yeast health mate?
 

bum

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Guysmiley54, on a number of occasions MHB has detailed the reasons why it is better to pitch dry than to rehydrate following any method other than the exact manufacturer's instructions. I can't recall what any of them were... <_< ...but if you're able to find these posts in a search then your question might be answered.
 

The Village Idiot

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I just bung it in some cold tap water, give it a stir and wait till it's creamy/foamy.

Used to make my beer out of 95% tap water and didn't get infections, and still often diluting wort with tapwater - so not too worried about using it for rehydrating yeast.
+1 I really think we get a bit too paranoid about tap water and its "cleanliness". Never had an issue with warm or cold tap water. Many a kit brewed with good old tap water.
 

Nick JD

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edit: Except Nick ;) Do you find that cold water is an issue for yeast health mate?
Tap water is just about right most of the year in the Goldie. I always bring my yeast out of the fridge a few hours before rehydrating though.

TBH, you have to really **** it up to have issues with dry yeast.

I never pitch Wyeast straight into the fermenter - that shit is unpredictable. Especially if it came in the mail.
 

thylacine

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I use to rehydrate until I experienced the two bad batches of Nottingham (a couple years ago) that was around. ie. so I pitched another yeast type dry because the wort was ready and the rehydrated 'Not' was quite unusual. As in stunk badly... (is there a good stink?)

Next morning after the pitch, krausen was still forming in a similar time frame to previous rehydrated experiences. Wish I would have tried the same much earlier. eg. making a double batch then pitching the same yeast, but one dry and the other rehydrated.

http://www.aussiehomebrewer.com/forum/inde...59308&st=20
 

eamonnfoley

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I just clean a coffee cup, put spring water in it, heat in microwave for a few minutes until its jumping out of the cup, let cool to lukewarm (with the help of fridge or freezer), put yeast in, wait about 15-20 mins, then pitch. Although let it cool down before you pitch to avoid cold shocking the yeast.
 

slash22000

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Here you go...
linky
The information provided in that link contradicts the Fermentis instructions? Fermentis says 24C - 30C is ideal for rehydrating, whereas that document says ideal temperature is always between 34C - 40C?

The document also states to pitch within 30 minutes of hydrating whereas the Fermentis instructions take 45 - 60 minutes?

I would imagine Fermentis know how to use their own yeast, but I wonder why there is such a disparity? :huh:
 

dammag

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I use a small Pyrex jug. Give it a good clean in boiling water. Put some foil over the top while it is too hot to handle. When it has cooled down a bit, put some filtered tap water in it. Put it in the fridge, covered in foil, until the glass is no longer hot to the touch. Put it on the bench and let it equalise to room temp. Sprinkle in the dry yeast that has been out of the fridge for a couple of hours. Make some creamy yeast.

This is pretty simple and gets good results, normally using US05.
 

NewtownClown

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The information provided in that link contradicts the Fermentis instructions? Fermentis says 24C - 30C is ideal for rehydrating, whereas that document says ideal temperature is always between 34C - 40C?

The document also states to pitch within 30 minutes of hydrating whereas the Fermentis instructions take 45 - 60 minutes?

I would imagine Fermentis know how to use their own yeast, but I wonder why there is such a disparity? :huh:
hey, I just found the link that another had referred to in an earlier post in this thread....

From what I read, 34-40 is the "optimum" temp and will return a higher number of viable yeast. 24 - 30 is ideal because you have a greater margin of error ie: if it gets over 30 there is no problem.

Also , the optimum and ideal temp may vary from brand to brand. But from the copious amount of "internet" research I've done in the last few hours, this doesn't appear to be the case.

As for the time, again its probably a "margin of error" case. At optimum temp, 30 minutes is probably right.

My assumptions are that at 27-30c, waiting 45-60 min then pitching, I can't **** anything up. I could take the risk of trying to recover 100% yeast cells and pitch when all those cell walls are at their most effective for controlling osmosis and possibly pitch a bunch of mutants.

To sum up, there is a best way and then there is a safer way, and that is what you will find to be a manufacturer's reccommendations
 

pcmfisher

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hey, I just found the link that another had referred to in an earlier post in this thread....

From what I read, 34-40 is the "optimum" temp and will return a higher number of viable yeast. 24 - 30 is ideal because you have a greater margin of error ie: if it gets over 30 there is no problem.

Also , the optimum and ideal temp may vary from brand to brand. But from the copious amount of "internet" research I've done in the last few hours, this doesn't appear to be the case.

As for the time, again its probably a "margin of error" case. At optimum temp, 30 minutes is probably right.

My assumptions are that at 27-30c, waiting 45-60 min then pitching, I can't **** anything up. I could take the risk of trying to recover 100% yeast cells and pitch when all those cell walls are at their most effective for controlling osmosis and possibly pitch a bunch of mutants.

To sum up, there is a best way and then there is a safer way, and that is what you will find to be a manufacturer's reccommendations

And then again you could just not worry about all the bullshit and toss it in dry and defy anyone to tell the difference in the finished product :rolleyes:
 

mikec

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I remember someone posted up a link a few months back, to a very comprehensive report by a couple of guys OS who had done a pretty extensive study.
They compared the results of pitching dry yeast straight into the wort, versus re-hydrating and then pitching.
The results showed pretty conclusively that there was two tenths of stuff all difference in the end result.
 

jaypes

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If you read the datasheet of US-05 it says 2 methods on how to pitch, first is the re-hydrate method at 27C plus or minus 3C wait 15-30 mins (3 beers) then maintain a gentle stirring for 30 mis then pitch the cream into the FV.

Or the "She'el be right" method - pitch dry yeast directly into the FV, wait 30 mins (3 beers) then aerate.

There was a good article in last edition of Homebrewer stating that you will lose 50% of your yeast if pitched dry.

I have not experienced any real difference in either method but YMMV
 

NewtownClown

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And then again you could just not worry about all the bullshit and toss it in dry and defy anyone to tell the difference in the finished product :rolleyes:
Absolutely!

However, the debate over dry pitch or re-hydrated pitch has been thrashed for years on this and other fora.

The topic is: Re-hydrating Yeast Temperature... :rolleyes:
 

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