how to rehydrate yeast

[Harbrook]

Hi,
I'm from the UK and will be starting my second brew this weekend.
Last time I had some problems pitching the yeast by simply following the instructions on the kit. The kit said to pitch the dry yeast straight on top of the wort, which i did evenly, The wort was at 70f
Firstly, I didn't airate to wort enough before pitching, not good. Secondly, I didn't stir the yeast in after it had naturally hydrated, meaning I was left with clumps on top of the foam. This undoubtedly is the reason that i have struggled to get the first brew down to the target FG. I think half the yeast must have been left floating on the top!
Please could you guys firstly let me know the best way to pitch the yeast, I understand that it would be a good idea to rehydrate the yeast prior to pitching, but i would like to know the simplest way to achieve this. (as much detail as possible would be greatly appreciated.)
Is it a risk to rehydrate?, if its not that simple, please would someone let me know the best way to pitch it dry.
Many thanks in advance.

 

[LostHopper]

I've pitched it dry right in carboy without any stirring and it did fine.

To rehydrate I boil about 6-8oz of water in a pyrex measuring cup then let it cool to under 90 deg F.
With a sanitized spoon I stir in the dry yeast and let it sit on the counter with a sanitized piece of foil as a lid.
It will get milky and maybe a little foamy.
I will use the sanitized spoon to stir it up right before pitching into carboy.

I think other factors could have influenced your FG. Pitching dry yeast is pretty foolproof in my experience.

 

[Enemygod]

I agree with LostHopper. I've pitched dry yeast without re-hydrating many times and I've never had a problem. It almost sounds like you received really old or maybe even bad yeast. From what I've read the main purpose for re-hydrating yeast is to get your fermentation started a little quicker and wont affect your FG.

 

[McKnuckle]

Take a half cup of tap water at 95-105ºF and set aside in a small, shallow bowl. Best practice would be to boil first, then cool, but I never do that.

Sprinkle the dry yeast evenly on the surface of the water. Cover it with plastic wrap. Wait about 15-20 minutes, til the yeast have swollen into a moist clump, and some have become submerged.

Take a sanitized spoon or any similar utensil, and stir the yeast into the water until it's a well integrated, creamy mixture. Dump it into the aerated wort. Don't stir.

[Edited to correct temperature. It does matter - Google it.]

 

[Jim311]

I don't even bother rehydrating. The give you a gazillion more yeast cells in that pack than you probably need for the average beer anyway.

 

[Harbrook]

this seems to be the ever conflicting question.. to rehydrate or not to rehydrate..

 

[TexasDroughtBrewery]

Yeah, I pitch dry all the time and never had any issues but this is a conflicting and controversial topic as mentioned.

 

[Harbrook]

Yeah, I pitch dry all the time and never had any issues but this is a conflicting and controversial topic as mentioned.

do you stir after pitching?

 

[JONNYROTTEN]

I've never rehydrated,never stir ever and skip aeration half the time. Never had a single issue reaching FG and yeast always takes off within a day.

 

[jmcdaniel0]

do you stir after pitching?

I re-hydrate simply because that is my habit from wine making. My grandpa always told me to re-hydrate for wine, and thats how I do it. He could have been wrong, yeast will multiply until the sugar is gone or the ABV gets to high for them. Whichever happens first. I honestly think you are ok doing it either way.

I stir for the same reason.

 

[treebeerd]

Not sure where, probably on here, but I've read that rehydrating at temps from 105-95 F is best (after cooling from boiling). I usually use less water, around 3 fl oz per pack of dry yeast. I have done this countless times with no problems in fermentation. I have also pitched dry yeast right on top of wort without problems. I usually rehydrate for bigger beers to make sure the yeast are as healthy as possible.

 

[TexasDroughtBrewery]

do you stir after pitching?

After I pitch the yeast I close the lid to the carboy and give it a good shake.

 

[GHBWNY]

I've done both and don't really see a difference in the beer. Maybe in theory, rehydrating helps lessen the shock of the yeast diving into its new environment? Like splashing yourself with water before jumping into the pool? Dunno. I do it because in my mind it *seems* more beneficial to the yeast than not doing it. I get the wort oxygen-ready (aerate), toss in the rehydrated yeast, give it one unnecessary, gentle stir.

 

[McKnuckle]

Whether one notices a difference in the beer is unrelated to the fact that there is a legitimate biological reason for rehydration:

"The idea is to combine water and dry yeast in order to “wake up” the yeast and restart its metabolism. When pitched directly into wort, the sugars that are present can prevent the yeast cells from drawing enough water through their cell membranes to kick start their metabolism."

Good article (not the source of the above quote):
https://www.northernbrewer.com/connect/2010/06/the-importance-of-being-hydrated/

 

[GHBWNY]

Whether one notices a difference in the beer is unrelated to the fact that there is a legitimate biological reason for rehydration:

"The idea is to combine water and dry yeast in order to “wake up” the yeast and restart its metabolism.

Rehydration "wakes up" the yeast, but metabolism doesn't "kick start" in the absence of food. It's like saying that our appetites kick start in the presence of water. Nah, they kick start in the presence of an appetizer!

 

[Sadu]

Way I see it, yeast are adaptable and are willing to overlook 1 or 2 mistakes that you might make.

So you can not rehydrate, or not aerate, or not pitch enough yeast, or pitch at high temps, or ferment a bit high/low, or pitch yeast that is a bit old. And things tend to work out fine. And to complicate things brewers will disagree (sometimes vigourously) on the importance on all of these things.

But when you start to do some/all of these things together that's when you might get punished for it. If you are not rehydrating and not aerating and the yeast has been on the shelf a bit long, that is yeast abuse. At best your beer won't be as good as it could be and at worst the fermentation will stall or another organism starts fermenting instead of the slow yeast.

A lot of people don't rehydrate and have success every time, and no doubt sprinkling the yeast is less hassle. That's great. But once you start getting into lagers and higher gravity beers it's worth paying more attention to the health of your yeast and rehydrating is one part of that.

That said, I pitch all my brews from leftover slurry or starters so I can't add any anecdotal evidence to the pile

 

[McKnuckle]

I think it's fair to say that there are many best practices in brewing that can be either followed or not, and things are often "fine" if they are not. You don't have to do everything perfectly to brew great beer. But at least if you ignore something, do it with the conscious knowledge of exactly what you are ignoring.

 

[TexasDroughtBrewery]

Way I see it, yeast are adaptable and are willing to overlook 1 or 2 mistakes that you might make.

So you can not rehydrate, or not aerate, or not pitch enough yeast, or pitch at high temps, or ferment a bit high/low, or pitch yeast that is a bit old. And things tend to work out fine. And to complicate things brewers will disagree (sometimes vigourously) on the importance on all of these things.

But when you start to do some/all of these things together that's when you might get punished for it. If you are not rehydrating and not aerating and the yeast has been on the shelf a bit long, that is yeast abuse. At best your beer won't be as good as it could be and at worst the fermentation will stall or another organism starts fermenting instead of the slow yeast.

A lot of people don't rehydrate and have success every time, and no doubt sprinkling the yeast is less hassle. That's great. But once you start getting into lagers and higher gravity beers it's worth paying more attention to the health of your yeast and rehydrating is one part of that.

That said, I pitch all my brews from leftover slurry or starters so I can't add any anecdotal evidence to the pile

I said I use dry yeast often but I do absolutely make starters for my lagers. This is probably the most accurate post on this thread yet.

 

[Beesnbeer]

Made a batch a week or so ago and used a new pack of US05. I rehydrated, but the package directions said to sprinkle on cooled wort.

 

[Harbrook]

Thank you all so much, this has been very helpful