this is what i use to rehydrate. it's worked great for the last five or six batches, so i figured i would post how i do it.

rehydration allows water to pass through the cell walls of the yeast and bring them back to life... something that the cells can't easily do in wort. john plamer recommends it... jamil zaniasheff recommends it... fermentis has a how to on their website... danstar tells you how to rehydrate as well. it's imperative... otherwise you lose about 60% of the cells when you just sprinkle directly onto the wort.

i have a 1 liter pyrex erlynmeyer flask, my brewmometer, a square of aluminum foil, and the packet of dry yeast... that's pretty much all you need to do it.

note: you can use a pyrex measuing cup in place of the flask. just have foil large enough to completely cover the cup. and, anything "pyrex" can be put directly on the heat, and straight into a water bath without shattering.

i start the process once my wort has cooled to 100° F... it usually takes another half hour, or so, for the wort to cool to pitching temps, which is just about how long the rehydration process takes. you want to time it right so you don't let the rehydrated yeast sit around... finish the process and pitch the slurry as soon as it's done.



there is one cup of warm tap water in the flask.

put the flask on the heat, and bring it to a boil.



let it boil for a minute or two... just to sterilize the water (this is also how you make sterile water... so if you see anything that calls for "sterile water", it mean water that has been boiled and cooled).

take it off the heat, put on the aluminum foil square to cover the mouth of the flask, and insert the brewmometer. i have an ove glove that i use to move the flask around... oven mitt, towel, etc... be careful, of course.

put the flask in a water bath so it can cool down to 100° F.



once it's cooled to 100° F, you're ready to sprinkle in the yeast. this recipe i used US-05 in an 11.5g packet, but this process will work for Mr Beer yeast packets, as well. make sure you spray the packet and the scissors with sanitizer... i keep a bottle of star san around just for stuff like this.



you'll see the yeast floating on top. DON'T STIR! just let it sit. 15 minutes. start a timer... clean up from your brew day.

once the 15 mins is up, i swirl the flask to mix the yeast into a cream/slurry and resuspend everything.

it'll look like this...



and you're ready to pitch. just pour the whole slurry into the fermenter. any dilution effect to the wort will be compensated by the alcohol produced during carbonation in the bottle... or i like to think it is.

it's super easy, and when i rehydrate my dry yeast, the beer has started fermenting within 4-6 hours. when i've only sprinkled dry yeast on, it's taken 12-24 hrs for fermentation to kick off... not good.

give it a try... i think you'll be pleasantly surprised at how easy it is and how much of a difference it'll make.

One thing I have never understood is the recommendation to just sprinkle the yeast on top and let them float without stirring. What is the purpose of not stirring?

By my thinking the yeast on the bottom of the pile are rehydrating but the ones on top are not. Yeast are microscopic so I find it hard to imagine that stirring the dry powder causes any harm and possibly helps by wetting the entire mass so all the yeast can rehydrate. But, there must be a reason so many sites and yeast manufacturers recommend letting the yeast island float undisturbed.

yeah, that's something i've wondered about, as well. but, you're right, they all say "Don't Stir!"... so i don't stir lol.

Very nice Chunk! This ties in well with the current BBR-BYO experiment!

Nice Job Chunk!

I do something very simiar, but with a pyrex measuring cup and the microwave.

Nice pictoral!

that'll certainly work, as well... i kinda geared this off of some of the steps to make a yeast starter... easier to make the transition when i start brewing larger batches

I would like to try, but looks to involved.

not in the least! it seems complicated, but it's really no harder than boiling water and cooling it in the sink... and setting a timer lol. the whole process takes about 30 mins... i do it while my wort finishes cooling.

try it....I am sure you will quickly realize it is very easy...

+1! Rehydrating yeast is no harder than brewing a Mr. Beer batch!

Nice thread Chunk...exactly what I've been doing. I also dont' stir, but I think I usually rehyrate at a lower temp, I may have to check the temps from now on to make sure I'm in range of close to 100*.

Good info, Chunk!

I use a pyrex cup covered with microwave safe plastic wrap and nuke until it boils, then place in the fridge. It takes a while to cool this way. The flask looks like a nice alternative.

A store attendant at Austin HBS recommended Go-Ferm for yeast re-hydration, so I tried it. It seems to yield better fermentations- but who knows. I think the main thing is just to re-hydrate.

I've become very lazy when rehydrating lately using 85-ish degree tap water and a gentle stir to start. Prior to pitching, I give it a vigorous stir to kick everything up into solution and pour.

I also use the pyrex measuring cup and microwave approach.

Note that different yeast manufactures do have different temperatures and instructions. Danstar, for example, is more involved. Once the yeast has been stirred in, add small amounts of wort every few minutes to gradually bring the yeast to pitching temp.
Danstar rehydration and usage

Also note that when rehydrating dry yeast, there is no need to aerate the wort.

For Real?

yeah I have heard that about Danstar, but do not buy it....they assume you do not need to aerate since you are basically over pitching...but in reality you are most likely not...

Yeah, it goes against everything we know about yeast needing oxygen. I dont' buy it either. As far as tempering the yeast with wort to match up temps, thats a good practice since you don't want to shock the yeast. But with such a small sample while rehyrating I think it would cool down fairly easily unless you are pitching at very low ale temps.

Also, it's very important to use sterile water (cooled pre-boiled tap water)...it's been said you dont' want to use wort or anything like distilled or RO water.

From what I see, it's not just Danstar. Fermentis (S-33, S-05, etc) only instructs to aerate when pitching dry yeast directly: "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 and then mix the wort e.g. using aeration."

btw - saw this experiment from a few years back which I found interesting. Some good discussion, too.
Dry yeast experiment

Yeah this is the sort of instructions I like to see, good ol pictures, don't have to do any of that fancy smancy reading if I dun wanna. :P

Great tutorial Chunk, I think I'm going to give this a shot on my next brew, looks simple enough.

Also I think we have the same counter tops. :P

I thought the same thing until I tried it.It couldn't be easier and you have all that time while cooling your wort.

Nice job Chunk

thanks for the feedback, everyone!

Now I need to shop for a Pyrex something for rehydrating. I've been doing it in a cokctail tumbler and feel a bit ghetto after seeing the laboratory equipment.

I thought the same thing until I tried it. I did the same thing pretty much except in a pyrex bowl. It ends up being much easier than it sounds.

http://www.sciplus.com/category.cfm/subsection/4

they have good prices... but you'll have to pay for shipping. i ran across this compamny when i was pricing equipment for a summer camp at the science center where i used to work... their catalogs are easily the greatest catalog i have ever seen.

but, a 2 cup pyrex measuring cup will work equally as well... i used one , as well, until someone on the forums actually sent that flask to me.

Hey mods, perhaps this should be a sticky!

I thought it already was....

I have been fooled before!

I've never understood the "don't stir" I always have stirred the hydrated yeast right b4 pitching and never had a problem, maybe I should try the no stir method, however my lag time since I started hydrating (and stirring) has never exceeded 8 hours and often as little as 4 hours. Maybe the no stir would produce a zero lag and cause instant fermentation.... My brewing motto, if it aint broke don't fix it.

Oh and nice pictorial Chunk !!!
Well done Sir !!!!

Sounds like you've got it right, mr bill... I stir right before I pitch as well. Gets everything "creamed" and resuspended.

I guess it all depends on the yeast you are using. Safale US-05 Different instructions for different brands. I've noticed better results rehydrating my yeast for sure. Shorter lag time, better fermentation...and better beeer in the end.

I usually sprinkle the yeast in a cup or so of boiled and cooled tap water in my flask that was covered with foil. Let it sit sit 15 minutes, stir, sit another 15 minutes and give it a good mix into a liquid slurry prior to pitching. I think ultimately we should note the different directions per package...maybe there is not just one perfect method.

It's simple. The only hassle point is timing. It mostly coincides with the busiest last 30 minutes of the brew. But it's still worth the effort. Dry yeast is "defenseless" and just not ready to go to work.

seems there is some confusion about when you should stir the dry yeast...

manufacturers say to just sprinkle to dry yeast on top of the sterile water. at this point, you just sprinkle, and wait... DO NOT STIR. set the 15 minute timer... when the timer is up, THEN you stir/swirl the yeast to make the slurry all creamy and resuspend all the cells. some say to wait another five minutes at this point, then stir again, then pitch. i skip the second wait, and just pitch the creamy slurry after the first timer.

also, if you wait until your wort is completely cooled to pitching temps, then start the rehydration steps, you won't have to worry about timing it with the end of cooling the wort. the wort will be fine for the added 1/2 hour it takes to rehydrate... as long as the lid stays on the brew pot and you were sanitary/clean during the brewing process.

Since this has become a sticky, it seems worthwhile to point out that the instructions given in this pictorial for S-05 are quite different than the manufacturer's instructions.

It may be good to make note of that upfront and/or make adjustments.

From Fermentis:
"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 (80F ± 6F). 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.
Alternatively, pitch dry yeast directly in the fermentation vessel providing the temperature of
the wort is above 20C (68F). 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 and then mix the wort e.g. using aeration."

the only comparison i've made between this method and the methods directed by the manufacturer are that both methods will give you the end result of rehydrated yeast.

i've used this method for both danstar and fermentis dry yeasts with great results.

1 cup of water (which i use) is about 20 times the weight of the 11.5 gram yeast packet.... that way no continuous stirring is necessary, since the greater volume of water will allow the cells to rehydrate without agitation (which you need in a smaller volume to ensure the cells get equally exposed to the water).

like i said... this is what i do. if you have another method, feel free to go about it that way. but this has worked for me, regardless of the manufacturer of the dry yeast, so i thought i would post it for everyone.

Yes, you have rehydrated your yeast, but is it the same end result?

Beating the dead horse, but if you say rehydration is imperative, it seems you would want to treat the yeast as best you can by following the specific procedures. 100 degrees just seems much higher than recommended. And then pitching after only 15 mins. will most likely be at a much greater temperature than the wort. I believe temperature shock can lead to bad fermentation, off flavors, etc. If this has worked for you, fine.

For many, following the instructions, which could include pitching without rehydration, has also worked.

From what I have seen they recommend a range I am sure you can find a value that it will work for every dry yeast at least the major ones

It's not rocket science a degree or two or a ml here and there in the overall scheme will not matter much.

Yes, S-05 is 80F ± 6F. Again, 100 degrees that you are using is much more than a degree or two. And when you pitch that only 15 mins. later into much cooler (hopefully) wort, you are most likely shocking that yeast .... risking improper fermentation, off flavors, etc. I thought healthy yeast was the whole point of the current MUST REHYDRATE message.

you are correct you should follow the yeast manufacturers rehydration process...

on the shocking the yeast....that is why they suggest adding small amounts of your cooled wort to the rehydrated yeast to slowly acclimate the yeast to your pitching temp, which is also part of the rehydration instructions...

Damn dgs.... Chunk spends some time to make a very informative
pictorial post that would help people and all you do is bust his balls ??? Most experts agree dry yeast should be re hydrated.
But as I have often said... it's your beer your call. You don't want to do it, that's just fine, your beer. Don't rain on Chunks parade just because you believe differently.
As Pudge has asked a couple times and I take the liberty of quoting another thread.




I believe several of us are waiting for a response to this question as if you have solid info backing up your claim I'll
rethink my re hydrating practices.
I normally don't get all fired up over brewing practices because there are infinite ways to achieve good beer. But when someone spends the time to create a informative post with "SOLID" info I dislike it being trampled on.

Again, I am not saying to not rehydrate. I do rehydrate. But I can also understand why some may not. Fermentis, for one, even gives this as a valid option.

"But when someone spends the time to create a informative post with "SOLID" info"

That is where my problem lies. The post does not follow the Fermentis instructions. Perhaps I missed something, but yeast in one cup of 100 degree water after 15 mins, I estimate, will still be 90+ degrees. Pitching that into cool wort is not SOLID practice. I am not certain this will provide better yeast health than dry pitching.

I imagine I can come across as an a$$, but as others have expressed, there seems to be a message recently that those who do not rehydrate are committing some kind of yeast abuse. There are many trade-offs and options in brewing. As many say, it's your beer...

Kinda late. Good night.

Look, I've posted this because it works. It's worked every time I've used this method. I based it of what others have reported, as well... Read a TON of posts on rehydration over on HBT... And this is similar to how Palmer and the guys on the BN have described rehydration.

If you want to follow manufacturer's directions to the T, then feel free. But sometimes it makes the most sense to leave well enough alone. It works. It will continue to work. And it is the easiest and most sime method I've found.

Our resident "Yeast Police" has spoken.......

I give ya a star for following directions !

I don't know why I'm the "yeast police", as I don't think I was pushing one way or the other on whether people should rehydrate.

But since this is the internet, it's about time we had a car analogy

If someone is saying it is imperative to rotate your tires, I don't think following generic, general instructions for all types & brands of tires is going to result in the claimed benefit. And I can imagine it can be more costly than not rotating if done incorrectly.

I know. Analogies can be picked apart, but we needed a car analogy.

I love car analogy's ..... and you are right can be picked apart
If your tire dealer is worth his weight in salt he will rotate for you for free on a monthly basis. In a perfect world rotating your tires daily would be ideal.... You can't do it enough for the obvious reasons. If your a car guy and understand tire wear and why they wear the way they do....but I digress......
I'm just messing with ya now dgs. I understand where your coming from on the yeast thing, let's agree to disagree..

I'm confused...which one of you guys is rotating my tires daily and must you rehydrate the yeast before you use it to patch a tire?

I picked up a small Pyrex measuring cup yesterday at a kitchen store for rehydrating yeast. $1.99 and it has markings in ml making it easy to get the right 10:1 ratio. I just tried it with RO water in the microwave. Not such a good idea. Bzzzzz and nothing until... boom. The water instantly boiled/flashed and blew 90% of it out of the container getting the entire interior of the microwave soaked. For my next attempt I used plain tap water which boiled more controlled.

yeah they say tap has the mineral content needed for the yeast to properly rehydrate anyway... just something else i read... not looking to start another debate lol

Aw come on. How about another three pages and then a push to make a sticky about the proper water to use for rehydrating. Maybe even a heated argument about which shape container is best.

Hey, you're the one having issues trying to boil water. Not us. I'm not saying... I'm just saying...

That's kind of scary. I've read that it's theoretically possible for that to happen, but I've never heard of anybody every actually having it happen to them. Once the measuring cup gets some scratches on it, I think that can't happen anymore.

I've read the same thing. I don't remember where or I'd post a link, but I think it was pretty recent.

Ok... sorry to resurrect this thread, but only "Pyrex" labware can be put directly on the heat of the stove. DON'T PUT YOUR PYREX MEASURING CUP DIRECTLY ON THE HEAT! Yes, I just learned that the hard way earlier this week... shards everywhere when the cup exploded... thankfully, i "Matrix" dodged everything when it blew, and i din't get burned. thankfully.

they can be used int he microwave to boil water, then transferred directly to the ice bath without breaking, so there's that... but don't put them directly on the stove.

Do you have an electric stove? Even pyrex labware should probably have a metal spacer of some kind between the burner and glass if it's electric.

I use an Erlenmeyer flask on a gas stove top. I still try to do temp changes gradually though.

never had a problem with the knock-off "pyrex" erlynemeyer on the electric cooktop... maybe it it were electric coil, i could see that being an issue, but we have that ceramic cooktop electric stove... no problems thus far.

Yeah, I meant the old-school coil type...the ceramic cooktop kinda already has a built-in spacer.

chunk, thanks for this guide. I've been using dry yeast due to cost lately and through rehydrating, I've seen both batches take off within 12 hours. Both put in the fermentation fridge at night and both showed activity the next morning, love it!!

One question though, would it be ok to sub bottled water for the boiled and cooled water? We are only boiling to sterilize right? I would heat the water in the microwave to 100* and then go from there. Do you see any issues?

Boiling sterilizes but also removes dissolved o2 from the water. Now, I don't know if that's something we're going for, or if it's just a byproduct of boil sterilizing the water.

To be safe, boil. That said, I'm betting you'd be fine just using bottled water heated to the appropriate temp.

I don't think the removal of o2 matters. Even if you boil and remove it, you are going to oxygenate the wort anyways. A little oxygen in with the yeast doesn't seem to be a big deal.

I might try this on my next batch and see how it goes. Then again, I am brewing the day before I leave on a week long trip and won't be able to watch it so I might wait until the batch after that one lol.

I bought a case of the little 10 oz bottled waters. My last few
batches I have poured out some water and added the yeast at
room temperature a couple hours before pitching. No issues so
far but I never had any yeast related issues pitching dry either.

That's actually a neat little trick. I never thought of that.
File that one away for future references. Thanks!

yeah, seems good, HJ... but the few hours might be a little bit too much time for the yeast to sit around without being pitched... i think you want to pitch about 15 mins after the granules fall to the bottom of the water. that way, they've had time to rehydrate without dipping into their nutrient reserves that they need once the cells are introduced to the wort.

Yeah you may be right usually it's probably only in there 30
minutes to an hour but I have not really timed it. Probably I
have been adding the yeast to the water bottle sometime during
the boil.
I wonder though about rehydrating in hot water. Something
just seems wrong about that method. I would be afraid of damaging
the little buggers.

Warm water is good, hot water is bad.

I believe cooler water is ok, but it takes longer.

100° F is what i shoot for... and just let it cool naturally while i wait the 15 mins before pitching. seems like it cools pretty quickly.

So maybe 2 hours in a water bottle is not so bad?
Stink will be along shortly to staighten us all out ;-))

As long as DGS doesn't try to spank us again!

What?

So the reason we rehydrate in water and not wort is because the yeast can be shocked by the wort (the sugars...not the temp) and potentially lose 50% viability, right? And the temperature of that wort should be <70 degrees, right? So if the problem with direct pitch is the fact that it's wort and not water, why can't (or actually, why shouldn't) we pitch to <70 degree water? Are you shooting for 100 degrees because that's "cool enough" to not kill the yeast? or is there some other logic for the 100 degree rule? Do the yeast absorb warm water better than cool water? I could buy that.
I'm just trying to understand the science of it as opposed to "it works for me and I haven't had a problem yet."

I believe you're correct BiG Z, that yeast absorb warm water faster/better than cool water.

I think I may try this out as well, seems like a much easier way to rehydrate (even though the other way is still really easy).

Guess I need to brew up a quicky batch to try this out on.

Well if warmer water is ideal, why not float the water bottle
in a sink or bowl of hot tap water. If you are brewing a canned
kit and warming the extract cans anyway? it would be a good time
to warm it?

I like that idea HJ.

I believe you want to use warm water because yeast act faster at higher temps( of course not too high) they ferment faster at high temps right?

The point of rehydrating is to allow the yeast time to rebuild their cell walls before they are introduced into a hostile environment. I would assume you could rehydrate in room temp water it would just take longer, but I am just guessing at that.

I usually use 80-90 degree water and it is just fine.

the wort is too acidic and too full of sugars for the yeast to properly rehydrate... and yes, i think 60% of the cells die if you just sprinkle the yeast granules on the wort. sterile water, on the other hand, will pass through the yeast's cell wall (osmosis) and rehydrate the cell, itself. and, 100° F is not hot enough to kill the cell, but warm enough for the yeast to start a little more quickly without harming the cell... like getting into a nice hot tub... gets the blood flowing, feels nice and cozy and relaxing

i think the reason we pitch into <70° F wort is to prevent the off flavors and "hot alcohol" taste that can develop in the initial stages of a fermentation that is too warm... pitch at or a touch below fermentation temps, right? you could ferment beer at 100° F, and the yeast would love it... they'd tear through fermentation like that. but, that wouldn't taste very good for us, so we need to pitch where we want fermentation temps to be so the temps don't "spike" out of control.

Just an update on the water bottle trick. I brewed wednsday 10
gallons so I took 2ea 10 oz water bottles and placed them on top
of my infrared heater for about 30 minutes. They were warm to
the touch but not hot. I then poured a couple oz of water out
of each one and put one pack of US 05 in each bottle, shook them
up and proceeded with brew day. They probably sat 4-5 hours and
really did much better than when I had pitched them at room temp.
Pitched one in each fermenter bucket.