Rehydrate?

[geh4rig]

Is it necessary/better to rehydrate dry yeast .. I've read recipes that say to just pitch the dry yeast I've read others that say to rehydrate first?

 

[NordeastBrewer77]

'Necessary'? No. Recommended? YES!

You lose about half your cell count, give or take, when pitching dry directly. You should always rehydrate dry yeast.

 

[geh4rig]

Thank u., and boiling water, letting it cool, then adding the yeast is the best way to rehydrate?

 

[hopsalot]

this is what i do

http://www.fermentis.com/fo/pdf/Tips-Tricks.pdf

"After the wort has been boiled for at least 15 minutes collect the volume
required for rehydration and leave to cool to the required temperature.
Rehydrate the yeast for 30 minutes. The rehydration should end at the
same time as you start transferring the wort to the fermentation vessel.
Pitch immediately into the tank after checking the temperature of wort."

 

[NordeastBrewer77]

Thank u., and boiling water, letting it cool, then adding the yeast is the best way to rehydrate?

Yeah, if you're using tap water, pre boil, cool to room temp and rehydrate. Many times for brewing I use bottled spring water, so I just use a bit of that to rehydrate my yeast. If I use tap, I boil it up in the microwave to sterilize it before rehydrating.

 

[rifraf]

I read in a thread in here that it's actually better to rehydrate in 90ish degree pure water, and that you only want wort if you're doing a starter.

Something like while rehydrating the cells just absorb everything in the liquid, sugars and all which is bad for the overall health. Once the cells are rehydrated they can actively keep chemicals/sugars etc out and it's ok to put them in wort.

This is paraphrasing, I'll try to find the thread. FWIW I rehydrate in plain water and pitch right into fermenter.

Edit: found it! https://www.homebrewtalk.com/f163/yeast-rehydration-etc-290327/

 

[monkeymootj]

I have also heard to rehydrate in boiled water cooled to 90 to 100 degrees (Palmers "How To Brew") However, the guy at my LHBS said not to rehydrate. I rehydrated my us 05 in boiled tap water cooled to room temp (70 degrees) and have a fairly vigorous fermentation. Has anyone else noticed a difference rehydrating at different temps?

 

[Newmanwell]

I have much shorter lag times when I rehydrate. Mid 70s for 15 or 30 minutes depending on what the manufacture says.

 

[NordeastBrewer77]

I read in a thread in here that it's actually better to rehydrate in 90ish degree pure water, and that you only want wort if you're doing a starter.

Something like while rehydrating the cells just absorb everything in the liquid, sugars and all which is bad for the overall health. Once the cells are rehydrated they can actively keep chemicals/sugars etc out and it's ok to put them in wort.

This is paraphrasing, I'll try to find the thread. FWIW I rehydrate in plain water and pitch right into fermenter.

Edit: found it! https://www.homebrewtalk.com/f163/yeast-rehydration-etc-290327/

You sir, are correct. Rehydrate in water, NOT in wort. Rehydrating in wort is a starter and not needed for dry. As far as temps, I think that ~90 is the recommended temp that most yeast makers say to rehydrate. I'm not sure if there's a difference between 70 and 90, I've rehydrated at temps in between there and never bothered to look for a difference.

I have also heard to rehydrate in boiled water cooled to 90 to 100 degrees (Palmers "How To Brew") However, the guy at my LHBS said not to rehydrate. I rehydrated my us 05 in boiled tap water cooled to room temp (70 degrees) and have a fairly vigorous fermentation. Has anyone else noticed a difference rehydrating at different temps?

I sense an experiment on my next two batches using dry!

 

[wailingguitar]

Honestly, I don't see the point in rehydrating dry yeast. For one, it is generally considered normal to have active ferment within 12 hours... we sometimes say up to 24... personally I think 24 is too long and less than twelve is ok... How about 8 hours? Or 6? That is what I usually see when pitching dry... 6-8 hours for active ferment... Ok, so perhaps 50% of the pitched yeast doesn't survive, but you know what happens? It ends up as nutrient for the yeast that does... So, good start times... fewer steps... one less potential contamination source... I for one don't like screwing around with anything that is unnecessary, and if that unnecessary thing is a potential source for contamination... well, that clinches it.

At home, I pour the yeast into the bottom of my fermenter before I dump wort in, in a commercial setting I pour it through the manway into the unitank before I knock out. It's still going to do what it is supposed to do, which is make good beer, so why futz around with it?

 

[amandabab]

I've stopped bothering to rehydrate at all.
I never saw any difference in lag time, ferment time or any difference in the finished product.
Most dry pitched Fermentis strains show signs of starting within 3-4 hours, most Lalvin strains 12-16 hours (kinda settled into those two companies over the years).

 

[TimpanogosSlim]

just wanted to point out, the data sheet for nottingham yeast specifies that you should not use distilled water, that you should not stir it until after it has soaked up water, and that you should not add sugar.

notty works about any way you use it, but it may work better if rehydrated according to instructions. Basically, I figure that they are advising the safest way to wake it up.

 

[geh4rig]

So when u add the yeast to the water, u don't stir it in? It will soak up water? About how long does that take?

 

[rifraf]

So when u add the yeast to the water, u don't stir it in? It will soak up water? About how long does that take?

Not long at all. I usually turn on an electric kettle as I put my brew in the ice bath. It boils and I pour ~2cup into a bowl and cool to 90F, and sprinkle the yeast on top. I do all this in between stirring the wort and swapping out the ice water as it warms.

By the time I pour the wort into my fermentor the yeast is good to go.

 

[Newmanwell]

Here's an email I got from Keith Lemcke The actual question was in regards to stirring.

Thanks for your question.

You will probably continue to search for "definitive answers" in brewing as our response to many questions at Siebel Institute is "...it depends..." as there are simply too many factors at play in most areas of brewing!

Stirring can simply allow for separation of any "clumps" to make sure the largest amount of cells are rehydrated. Don't stir unless you need to, so pour the yeast across the surface of the water and allow it to stand for about 15 minutes. If you see it isn't uniformly dispersed through the rehydration water after that time, you can gently stir it. Some brewers don't rehydrate at all, but we find it improves yeast start-up by allowing wort to enter the cells more readily.

As Charlie P says, "Relax, don't worry..."

Thanks again,

Keith Lemcke

Is rehydrating necessary? No. Is best for healthy yeast? Research seems to point that way.