rehydrate dry yeast?

[Pinhead]

I've used the rehydrating instructions in the dry yeast sticky for my last two batches. For the past 4 years have just opened the package and dropped the yeast in.

I brewed two days ago and rehydrated the yeast, I've had no activity in the air lock so I opened the lid and nothing is going on inside.

The instructions tell you to float the yeast on water that is 104 degrees which is what I did.

I know hot water will kill the yeast how hot does it have to be to kill it?

 

[SleepyCreekBrews]

I imagine the kill temp varies from strain to strain, but the best advice is, follow the instructions on the yeast. 104F does seem a tad high though, generally the temps are in the 80-90 degree range. I'll add that it's highly recommended to match the yeast temp to the wort temp when pitching.

 

[yourlastchance89]

I've only used dry yeast a few times and I've rehydrated everytime. I know it's a hot button topic whether to rehydrate or not but I figured I don't have anything to lose by rehydrating, it's a pretty simple step, so I always do it typically the night before brewday and keep it in a sanitized flask in the fridge overnight. I have always cooled the water to 90 degrees or lower when rehydrating. 104 is kinda hot but I don't think it would be detrimental to the yeast. My guess if I had to surmise would be if you rehydrated and pitched the same day as brewday, going from 104 degrees rapidly to whatever far cooler temperature your wort is at, probably put the yeast in a cold shock and delayed fermentation. I would give it a few more days to see if activity occurs and if nothing happens, I would suggest a re-pitch, and then post your process more detailed on here to figure out what possibly went wrong. I like to cool down my rehydrated yeast before pitching specifically so I get a faster take off when it does come in contact with the warmer wort. My guess for you is the opposite occurred.

 

[Miraculix]

Did you use distilled or ro water for the rehydration? If so, that killed the yeast.

 

[auburntsts]

From what I gather the generic rehydration process is to warm sterilized tap water to between 95 and 105 deg F (depending on the strain). Add the yeast, cover, wait about 15 min then gently stir. Then cool to within roughly 10 deg of the wort temp before pitching. That sound about right?

 

[cubalz]

Did you use distilled or ro water for the rehydration? If so, that killed the yeast.

^I disagree with this completely. Whenever I use dry yeast (admittedly not very often, I almost always use White Labs liquid) I always proofed mine in 105f distilled water for 15 minutes, creamed it, and then pitched when it was within 10 degrees of my 65f wort. I have been doing it this way for well over 20 years and I make damn good beer in all styles.

 

[Kozwald]

I take 1.5 cups of water, throw it in the microwave for 2 minutes to boil, then cool it in the freezer to around 75 to 8- degrees. I sprinkler the yeast on the water, cover and let it sit for 15 minutes. I know the directions say not to stir but I usually gently stir it so all the yeast is submerged. After about another 10 minutes the yeast forms a nice creamy head. I dump the whole solution into the fermenter and typically see activity within 8 hours.

 

[Miraculix]

^I disagree with this completely. Whenever I use dry yeast (admittedly not very often, I almost always use White Labs liquid) I always proofed mine in 105f distilled water for 15 minutes, creamed it, and then pitched when it was within 10 degrees of my 65f wort. I have been doing it this way for well over 20 years and I make damn good beer in all styles.

Then either your distilled water sucks or you were very lucky that all the insides of those yeast cells which exploded due to high osmotic pressure provided enough ions to keep the few remaining ones from exploding to. Look up the school chemistry experiment with a piece of potato and distilled water.

 

[cubalz]

Lucky while producing a crap ton of excellent beer that wins comps? Give me a break. It works and I always saw fermentation activity within 12 hours. I have been brewing at least 1-2 batches a month since 1989. Do the math. This isn't my first rodeo.

 

[auburntsts]

Lucky while producing a crap ton of excellent beer that wins comps? Give me a break. It works and I always saw fermentation activity within 12 hours. I have been brewing at least 1-2 batches a month since 1989. Do the math. This isn't my first rodeo.

Just curious -- in your first post you said you "proofed" in distilled water. By "proofed" do you mean you added some kind of yeast nutrient and then yeast to the water vs just yeast into the water?

 

[Miraculix]

Lucky while producing a crap ton of excellent beer that wins comps? Give me a break. It works and I always saw fermentation activity within 12 hours. I have been brewing at least 1-2 batches a month since 1989. Do the math. This isn't my first rodeo.

You said that you "creamed" your yeast with the water, which implicates that you used a very little amount of water. The dead yeast cells, which make up a big percentage of the dry yeast, provided ions that lowered the osmotic pressure on the yeast. Or you might have added nutrients which basically would do the same thing. Otherwise the osmotic pressure would be so high that the distilled water would flow uncontrolled into the yeast cells till they burst.

 

[eric19312]

Did you use distilled or ro water for the rehydration? If so, that killed the yeast.

this can't possibly be right


edited:
This is probably not completely right (doubt all the yeast were killed) but has reasonable basis and I thank Miraculix for pointing it out..

Found this on Danstar TDS for BRY-97...emphasis added by me

Sprinkle the yeast on the surface of 10 times its weight in clean,
sterilized water at 30-35°C (86-95F). Do not use wort, or distilled or
reverse osmosis water, as loss in viability will result. DO NOT STIR.
Leave undisturbed for 15 minutes, then stir to suspend yeast
completely, and leave it for 5 more minutes at 30-35°C. Then
adjust temperature to that of the wort and inoculate without
delay.

 

[Miraculix]

this can't possibly be right


edited:
This is probably not completely right (doubt all the yeast were killed) but has reasonable basis and I thank Miraculix for pointing it out..

Found this on Danstar TDS for BRY-97...emphasis added by me

Sprinkle the yeast on the surface of 10 times its weight in clean,
sterilized water at 30-35°C (86-95F). Do not use wort, or distilled or
reverse osmosis water, as loss in viability will result. DO NOT STIR.
Leave undisturbed for 15 minutes, then stir to suspend yeast
completely, and leave it for 5 more minutes at 30-35°C. Then
adjust temperature to that of the wort and inoculate without
delay.

Exactly. The intensity of the lethal effect depends on the yeast / distilled water ratio. The more distilled water you use compared to the amount of yeast, the more yeast will die. If you use enough you kill every cell. We had those cases here in the forum.

 

[Pinhead]

Did you use distilled or ro water for the rehydration? If so, that killed the yeast.

I'm using filtered tap water that has been boiled cooled then reheated to 105 also float the yeast.

 

[Pinhead]

After reading all of the comments yesterday got my wine thief out, and my hydrometer and went out to test it. Great big creamy head on the beer. Closed it up and let it do its thing

 

[BobBailey]

The content of this thread is good reason to learn to separate the fly **** from the salt and pepper before taking any advice to heart. This is more of a pissing match than it is anything constructive.

Please people, read your responses before hitting the "Post Reply" buton.

 

[RM-MN]

I've used the rehydrating instructions in the dry yeast sticky for my last two batches. For the past 4 years have just opened the package and dropped the yeast in.

I brewed two days ago and rehydrated the yeast, I've had no activity in the air lock so I opened the lid and nothing is going on inside.

The instructions tell you to float the yeast on water that is 104 degrees which is what I did.

I know hot water will kill the yeast how hot does it have to be to kill it?

140F is considered pasteurization temperature, milk must be held at that temperature for 30 minutes to be certain. Hotter temps pasteurize faster.

I just spent the last hour reading at Beer Advocate about rehydrating yeast and pitch rates and viability. The consensus was there was no consensus and that direct pitching dry yeast works at least as well for most people as rehydrating and that rehydrating can at times give much worse results such as long or very long lag times.

I've pitched dry and I've pitched rehydrated. I've sprinkled yeast on top of the foam and left it and I've stirred the dry yeast into the wort. The only real difference I can notice is that I have to make sure the water for rehydrating is the right temperature and that I can't accomplish any meaningful work while I wait for the yeast to rehydrate as I need to be there to stir it at 15 minutes and pitch it at 30 except for the one set of instructions that said I needed to stir it for 30 minutes after the 15 minutes. Forget all that, sprinkle the dry yeast on the foam, pop the lid on and set it where it is cool.

 

[eric19312]

I've pitched dry and I've pitched rehydrated. I've sprinkled yeast on top of the foam and left it and I've stirred the dry yeast into the wort. The only real difference I can notice is that I have to make sure the water for rehydrating is the right temperature and that I can't accomplish any meaningful work while I wait for the yeast to rehydrate as I need to be there to stir it at 15 minutes and pitch it at 30 except for the one set of instructions that said I needed to stir it for 30 minutes after the 15 minutes. Forget all that, sprinkle the dry yeast on the foam, pop the lid on and set it where it is cool.

I'm a big fan of dry yeast because of the flexibility it allows in brew day scheduling. I try to always have a few packages on hand just like store malt and hops so if a brew day opportunity comes up I am not needing to figure out how to find time for the brew day and a run to LHBS.

But I am willing to take same time and care with dry yeast that I do with any other ingredient.

The dry yeast manufacturers provide instructions which allow for either rehydrating or direct sprinkle but consistently indicate a preference for rehydration. Sort of like the liquid yeast manufacturers who claim their package should be good for an ordinary strength batch of wort but then also either directly provide (Wyeast) or facilitate (White Labs working with Mr Malty) detailed pitch rate calculations and directions for building starters to get there. The people who make these products understand there is a best way to use them while also providing a reasonable rule of thumb shortcut. It is up to the brewer to decide which route to follow. So long as I remember to rehydrate my yeast at same time I am starting to chill the step is just not that inconvenient.

 

[RM-MN]

I'm a big fan of dry yeast because of the flexibility it allows in brew day scheduling. I try to always have a few packages on hand just like store malt and hops so if a brew day opportunity comes up I am not needing to figure out how to find time for the brew day and a run to LHBS.

But I am willing to take same time and care with dry yeast that I do with any other ingredient.

The dry yeast manufacturers provide instructions which allow for either rehydrating or direct sprinkle but consistently indicate a preference for rehydration. Sort of like the liquid yeast manufacturers who claim their package should be good for an ordinary strength batch of wort but then also either directly provide (Wyeast) or facilitate (White Labs working with Mr Malty) detailed pitch rate calculations and directions for building starters to get there. The people who make these products understand there is a best way to use them while also providing a reasonable rule of thumb shortcut. It is up to the brewer to decide which route to follow. So long as I remember to rehydrate my yeast at same time I am starting to chill the step is just not that inconvenient.

Some manufacturers only mention direct sprinkling on the package and if you want their info on rehydration you have to go on their website to find it.

 

[Kent88]

Maybe it isn't helpful to say this, but this is why, even for my one-gallon batches, I always make a proper yeast starter. I really like knowing that my yeasts are alive, healthy, and active when I add them.

 

[eric19312]

Some manufacturers only mention direct sprinkling on the package and if you want their info on rehydration you have to go on their website to find it.

This is likely because the 11 gram sachet is intended for home brewers while information on their website is provided for pro/large batch applications.

 

[Bobcatbrewing42]

Then either your distilled water sucks or you were very lucky that all the insides of those yeast cells which exploded due to high osmotic pressure provided enough ions to keep the few remaining ones from exploding to. Look up the school chemistry experiment with a piece of potato and distilled water.

In seven years of brewing, I have had almost identical results pitching dry yeast directly into the wort as with rehydrating. The cell count is so much higher with dry than liquid yeasts that it always seems to work. I use liquid when I need a specialty yeast but the cost is about double, storage is a problem and shat happens. I've had a smack pack burst trying to get the nutrient bubble to break (brew shop 40 miles away). White labs yeasts have a low cell count and seem slow without a starter. Starters work but kill another day, cost money. Saved yeast yields inconsistent results but seems to be the best when it is viable. It seems like every step that is added is another risk of contamination.

 

[IslandLizard]

[...] I figured I don't have anything to lose by rehydrating, it's a pretty simple step, so I always do it typically the night before brewday and keep it in a sanitized flask in the fridge overnight. [...]

That's definitely NOT a recommended procedure.
Pitch right after (properly) rehydrating, don't let the slurry sit without food (wort), all her sterol reserves will be depleted. That's probably worse than sprinkling directly onto the wort.

 

[ncbrewer]

That's definitely NOT a recommended procedure.
Pitch right after (properly) rehydrating, don't let the slurry sit without food (wort), all her sterol reserves will be depleted. That's probably worse than sprinkling directly onto the wort.

Danstar agrees with this. I asked Danstar about it and got this response:
"Our technical manager suggests that you don't go longer than 30 minutes after the start of rehydration before pitching the yeast into wort as the yeast needs nutrients. If there is a delay you could actually add more wort to the rehydration water to give the yeast something to eat while you are waiting to pitch it, so long as it isn't too hot."

 

[ncbrewer]

To those who have been successfully dry pitching: Fermentis instructs to pitch into wort over 68F if dry pitching, which is a big part of the reason I've been rehydrating - I generally pitch at about 64F. Have you been pitching into warm (above 68F) or cool wort.

 

[RM-MN]

I've pitched Danstar Nottingham into 55 degree wort and often pitch Fermentis yeasts into wort that is between 58 and 64. No problems with either.

 

[stz]

Do what works. Hydrate though if you want to follow best practice. If you don't hydrate then you'll kill a significant number of cells. This doesn't mean that there aren't still enough left over to finish the job, especially with yeast growth and dry yeast tends to be pitched on the high side anyway, but correct counts and hydrating dry yeast is best practice. Hydrate at 24-26C. After a while use some wort to bring it down closer to fermentation temperature prior to pitching. Here is the really contentious idea, why hydrate with unboiled tap water? Been doing it professionally for years without a single problem. Yes tap water isn't sterile, but it is sanitary. The kind of bacteria present isn't in significant numbers or ones which flourish in beer.

 

[Miraculix]

Do what works. Hydrate though if you want to follow best practice. If you don't hydrate then you'll kill a significant number of cells. This doesn't mean that there aren't still enough left over to finish the job, especially with yeast growth and dry yeast tends to be pitched on the high side anyway, but correct counts and hydrating dry yeast is best practice. Hydrate at 24-26C. After a while use some wort to bring it down closer to fermentation temperature prior to pitching. Here is the really contentious idea, why hydrate with unboiled tap water? Been doing it professionally for years without a single problem. Yes tap water isn't sterile, but it is sanitary. The kind of bacteria present isn't in significant numbers or ones which flourish in beer.

I completely agree. But I do boil my tap water because it is highly chlorinated, not because of bugs. I do not know what this chlorine would do to the yeast, so just to be on the safe side, I boil it off.

 

[h22lude]

Buy two packets and pitch right in the wort. Some yeast will die but with two packets, you will have plenty of yeast left.

 

[MaxStout]

All of my last 6 or 7 brews have been with dry yeast, most of them US-05. Of those, the first couple were rehydrated in 80-90F tap water and fermentation started out fine within a day, maybe 36 hours tops. With the last 4 or 5 brews I added Go Ferm to the warm tap water for rehydration. All of those fermentations took off like a rocket, within 12 hours or so. Of course, this is just a few data points, and YMMV, but the change I've encountered keeps me using the Go Ferm.

 

[RM-MN]

All of my last 6 or 7 brews have been with dry yeast, most of them US-05. Of those, the first couple were rehydrated in 80-90F tap water and fermentation started out fine within a day, maybe 36 hours tops. With the last 4 or 5 brews I added Go Ferm to the warm tap water for rehydration. All of those fermentations took off like a rocket, within 12 hours or so. Of course, this is just a few data points, and YMMV, but the change I've encountered keeps me using the Go Ferm.

Do you get noticeably better beer with the quicker starts?

 

[yourlastchance89]

That's definitely NOT a recommended procedure.
Pitch right after (properly) rehydrating, don't let the slurry sit without food (wort), all her sterol reserves will be depleted. That's probably worse than sprinkling directly onto the wort.

I didn't know that. Thanks for the info.

 

[cooper]

This is a great thread to prove there are many ways that work great. I've pitched dry, I've boiled tap water and cooled to 95 and rehydrated the yeast, and I've also taken a water bottle and poured about half of it out and sprinkled the yeast directly onto the room-temperature water and pitched a half hour later. ALL have been successful.

 

[MaxStout]

Do you get noticeably better beer with the quicker starts?

I noticed that the beers were a little cleaner, with less off-flavors. No way for me to know for sure if that was attributable to the yeast boost or not. Too many other variables. But the fact that my yeast took off faster is reason enough for me to continue using it. I know that Go Ferm is generally used for wine yeasts, but I don't think beer yeasts mind.

 

[EagleScout]

After some suggestions I was given for my first lager I've started making a starter for every batch, even when using dry yeast, using this calculator to figure out how big it needs to be.
https://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/
Sometimes it would take a few days to see activity without a starter but since I've started making starters for everything I usually see activity in a few hours.

 

[Miraculix]

All of my last 6 or 7 brews have been with dry yeast, most of them US-05. Of those, the first couple were rehydrated in 80-90F tap water and fermentation started out fine within a day, maybe 36 hours tops. With the last 4 or 5 brews I added Go Ferm to the warm tap water for rehydration. All of those fermentations took off like a rocket, within 12 hours or so. Of course, this is just a few data points, and YMMV, but the change I've encountered keeps me using the Go Ferm.

That sounds really interesting! Unfortunately, I did not find it reasonably priced in the uk... only really expensive for a one time dose or 1kg....

 

[nh_homebrew]

If I rehydrate dry yeast do I need to use it all or some? I know I can wash and reuse after its done fermentation.

 

[ancientmariner52]

The packets are sized for 5 gallon batches. Once you hydrate, it's awake and rarin' to go. If you don't intend to use it all, weigh out what you need dry, then hydrate.

 

[mabrungard]

I've summarized information on yeast rehydration studies from the past few years on the Bru'n Water Facebook page.

https://www.facebook.com/Brun-Water-464551136933908/?ref=bookmarks

 

[nh_homebrew]

Sorry I wasn't very precise. I should have worded it this way. If you hydrate a packet of dry yeast made for 5 gallons, can you use it for more than 5 gallons? Once the yeast cells populate doesn't it grow to be more yeast?