# Rehydrating Dry Yeast



## bevdawg (19/12/10)

Just after some advice on my rehydrated S05 yeast.

Did my second AG yesterday, went very well, chucked the pack of S05 dry yeast into 35c water and let sit for pehaps too long, as I was still trying to get my wort temp down. Pitched it at 22c, but about 1-1.5 hours after rehydrating. Didn't think too much of it but does not appear to be much action today airlock wise. Some condensation on lid.

Just wondering if the yeast was stuffed from sitting there for too long? I've read that it's fine to leave it for over 30 min but you just wont get the inital kick start you're after. Is this correct? Should I pitch another pack?

When I rehydrated it, I stirred it into the 100ml of cooled boiled water and it made a big bubble of foam on top. 

Any advice appreciated. I'm probably just stressing, but I spent 4 hours making this one


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## bignath (19/12/10)

Dont stress mate, all will be ok.

I'm not sure about which temps are ok and for how long, but i use US-05 A LOT, and what you are describing as condensation on lid means it's doing it's thing. Don't worry about the airlock - one of the most overrated pieces of gear brewers think they need to use. 

read up on using glad wrap over the fermenter hole instead of the lid. you hold the glad wrap in place by the o ring from inside your lid. Works well for a heap of brewers (myself included).

when i rehydrate us05 i boil some water while i am brewing and because i am a "no chiller", i put the wort in the fridge/outside/cold water bath to cool down. i do most of my brewing at night so as i go to bed i boil the kettle, then use the cooled boiled water in the morning to pitch my yeast when the temp of my wort has reached it's target.

I wouldn't worry about your rehydrating too much this time around. Obviously next time try to use cooler water but i wouldn't go pitching another packet just yet....

cheers on you going to All Grain and your first post too! Welcome to the forum.

Nath


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## bevdawg (19/12/10)

Cheers for the reply! I'm sure you know how it can be sometimes, stressing everything is going wrong after so much work 

I know the airlock is overrated but it really gives you comfort sometimes  There's condensation on the lid, not heaps, but the lid was also not quite airtight this morning as well. There's no real foam etc on the top either.

So the yeast is fine even though it was in the water for so long? Does it just mean it needs longer to start it's thing?

Thanks again!


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## bignath (19/12/10)

bevdawg said:


> Cheers for the reply! I'm sure you know how it can be sometimes, stressing everything is going wrong after so much work
> 
> I know the airlock is overrated but it really gives you comfort sometimes  There's condensation on the lid, not heaps, but the lid was also not quite airtight this morning as well. There's no real foam etc on the top either.
> 
> ...




Yeah probably just needs a little more time. 

I spent all night on tuesday (8pm - 5am) brewing back to back beers of the same recipe to go in two separate fermenters (i don't quite have the ability YET to do a double batch brew in one process). One of them has fired up well, the other has taken a bit more time to go nuts, and they are side by side in my ferment fridge.

Oh, and speaking of things that can go wrong, no matter how often i tell myself to check the tap on my fermenter before transferring my wort, i still get wet feet if i've had a few whilst brewing.


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## glaab (19/12/10)

If you have no krausen after 24 hrs I would throw in another pack, there is usually plenty of visible krausen by then and the longer you leave it if the yeast aint diong it;s thing yoru riskihng ifnection. I used to always rehydrate and swear by it but after using about 36 packs of 05 this yr and watching it fairly closely doing it both ways I won't bother anymore.


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## MHB (19/12/10)

The other school of thought, unless you know more about yeast than the people at Fermentis, follow their instructions, they are quite clearly written on each and every packet.
I'm not going to get into another 5 page flame war about who's right and who's wrong. I've sold thousands of packets of US-05, the only people who ever have any problems with it are those that **** with it.




It may be possible that you can get slightly better performance out of the yeast if you rehydrate it, but only if you follow the instructions given by Fermentis exactly, if you intend to rehydrate yeast read the specific instructions for US-05.View attachment Safale_US_05_CB.pdf

MHB


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## manticle (19/12/10)

I've both rehydrated and sprinkled straight in and have seen little discernible difference in either method (lag time, final beer, attenuation etc). That leans me towards sprinkling as it's one less vessel to clean and sanitise, one less step to stuff up.

I think freshness of yeast and good storage are probably much more important.


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## Online Brewing Supplies (19/12/10)

The guys at the BOP I use to frequent many years ago would make me wait with a jug of hot water and a thermometer till the temp was just right to rehydrate. Their bulk yeast was in an open type lunch box, funny I never got an infection.
Got me hooked on brewing.
GB


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## Fourstar (19/12/10)

MHB said:


> The other school of thought, unless you know more about yeast than the people at Fermentis, follow their instructions, they are quite clearly written on each and every packet.
> It may be possible that you can get slightly better performance out of the yeast if you rehydrate it, but only if you follow the instructions given by Fermentis exactly, if you intend to rehydrate yeast read the specific instructions for US-05.
> MHB



I always follow the second procedure noted. Observing the fermentis website, as you walk through their portals of homebrewing, craft and industrial that the recommendations change drastically. I say if you are *capable* of performing whats noted for the craft brewing methods, follow them.

as noted by fermentis.


> 2. Is rehydration necessary?
> To achieve *maximum viability* of the yeast we recommend that the directions are followed, either by re-hydrating in a separate vessel or in the fermenting vessel at elevated temperatures.



Other reason i have is noted below with a little math thown in for clarity.  



Fourstar said:


> ....
> I overheard some interesting information that Chris White (whitelabs) was discussing regarding the use of dry yeast. I believe he estimated cell death of dry yeast if not rehydrated of close to 50%. AKA pitching direct to fermenter.
> 
> Now using that information, see the following. The dry yeast packets state on their spec sheet each packet contains 11.5g of yeast and the viability at packaging is 6 * 10 ^ 9 (6 billion cells per g) which equates to 69 billion cells in a packet.
> ...


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## MHB (19/12/10)

Not suggesting that Chris White doesn't know his stuff, but he does flog liquid yeast for a living. I for one would like to see some independent evidence for that 50% fatality rate before I was too convinced; having seen similar numbers published for old pressed air dried yeast, rather than the more modern "Active Yeast".

In the interest of fairness, PDF I posted was from the Craft, rather than the Home Brew page of the Fermentis website, there it recommends (either sprinkled into the wort or properly rehydrated) 50-80g/HL (HL = 100L) that's 11.25-18g/22.5L (just quoting the manufacture, not discussing the merits of different pitch rates).

Not saying that it's a right/wrong choice, just before anyone decides to chuck some yeast in water and hope for the best THINK - if you don't have a thermometer in one hand THINK TWICE.
This is a good read http://koehlerbeer.com/2008/06/07/rehydrat...r-clayton-cone/, and the opening question reflects my personal experience as a retailer for the last decade so closely that it's scary.

MHB


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## glaab (19/12/10)

:icon_offtopic: isn't 69-65%=24.15, under 8% of 187.5, so that's 13 packs for 20L or >6 packs rehydrated?


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## beerbog (19/12/10)

manticle said:


> I've both rehydrated and sprinkled straight in and have seen little discernible difference in either method (lag time, final beer, attenuation etc). That leans me towards sprinkling as it's one less vessel to clean and sanitise, one less step to stuff up.
> 
> I think freshness of yeast and good storage are probably much more important.



I'm the same, have done both rehydrated (exactly as Fermentis says) and sprinkled straight onto wort. No noticeable difference, just a whole lot more time rehydrating. Now I just sprinkle. :beerbang:


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## MHB (19/12/10)

glaab said:


> :icon_offtopic: isn't 69-65%=24.15, under 8% of 187.5, so that's 13 packs for 20L or >6 packs rehydrated?



And people ask why experienced brewers are leaving AHB in record numbers, thanks for just adding one more reason to the list the place is filling up with wankers.

If you don't want to discuss Brewing (or are incapable) there are plenty or other places where I'm sure your insights will be valued, here they aren't. I went to your profile to give you a one star rating, didn't as it would have actually raised your standing.

MHB


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## glaab (19/12/10)

MHB said:


> And people ask why experienced brewers are leaving AHB in record numbers, thanks for just adding one more reason to the list the place is filling up with wankers.
> 
> If you don't want to discuss Brewing (or are incapable) there are plenty or other places where I'm sure your insights will be valued, here they aren't. I went to your profile to give you a one star rating, didn't as it would have actually raised your standing.
> 
> MHB



what's your problem tool?, am I wrong?, just saying it doesn't add up. aaaw, I wanted that star too


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## MHB (19/12/10)

I don't believe you; you put an OT flag out front and then just blathered.
If you have a point please make it, that at least might contribute something to the discussion. Trying to duck after the fact is fairly infantile.
Mind you I agree that a lot of what gets said about yeast doesn't add up, if I was brewing commercially I would be rehydrating, and/or building up an "Active Starter" (not the same) and inoculating a well proven pitch after doing a cell count. All conducted aseptically and with temperature control. But I'm not working in a brewery, I'm a home brewer.

MHB


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## glaab (19/12/10)

"wanker", "infantile", all valuable input for sure. Your just a cockhead Mark, another tough little girl behind the computer screen, hope you got the point this time.


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## Steve (19/12/10)

MHB said:


> if I was brewing commercially I would be rehydrating, and/or building up an "Active Starter" (not the same) and inoculating a well proven pitch after doing a cell count. All conducted aseptically and with temperature control. But I'm not working in a brewery, I'm a home brewer.
> 
> MHB



I was very surprised at one of the Wig n Pens brew days organised by the Canberra Brewers a few years ago when Richard just ripped opened a couple of boxes of SO4 and tipped them into the fermenter.


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## Fourstar (20/12/10)

MHB said:


> Not suggesting that Chris White doesn't know his stuff, but he does flog liquid yeast for a living. I for one would like to see some independent evidence for that 50% fatality rate before I was too convinced; having seen similar numbers published for old pressed air dried yeast, rather than the more modern "Active Yeast".
> 
> rinkled into the wort or properly rehydrated) 50-80g/HL (HL = 100L) that's 11.25-18g/22.5L (just quoting the manufacture, not discussing the merits of different pitch rates).



Interestingly during the see the beasts display there was some s23 pitched direct to wort, dead cells dyed and observed under microscope. Iirc, the fatality observed was something like 1/3rd from what we could see on the slide. I know it's not a proper count but a good marker for observation nonetheless.


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## MHB (20/12/10)

I hope you read the link in my post, or this might not make much sense and please understand this one point, I'm not against rehydrating yeast, just people doing it badly
When yeast is either pitching directly or rehydrated it must be handled properly; just a couple of degrees out on your temperature and you can kill half of the yeast.
The number of ways to harm your yeast whilst trying to "help" it I believe for most home brewers outweighs the benefits, that is also I believe the thinking behind Fermentis printing on the packet "Sprinkle into Wort".

To those brewers willing to rehydrate and/or build up a culture, more power to you, if you do it properly it will give you a better healthier pitch.
To tell people to chuck yeast in a glass and cover it with gladwrap is in more cases than not going to do more harm than good without providing a lot of supporting information specific to each yeast strain its bad advice to offer.

MHB


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## cKc (4/1/11)

A related question or two on rehydrating Safale US-05 yeast. I'm still learning so be gentle...

I recently rehydrated as per Palmer's instructions for an extract brew (Chapter 1 - A crash course in brewing). The first yeast-related step is _"Put 1 cup of warm (95-105F, *35-40C*), preboiled water into your sanitized jar and stir in the yeast. Cover with plastic wrap and wait 15 minutes.". _Then he moves on to proofing the yeast.

Note the temperature is much higher than recommended the PDF attached by MHB and generally recommended by brewers on this forum.

*Questions*


What is the likely effect of using the higher temperature water for rehydration? I wouldn't have thought 40C would be enough to kill any yeast cells...?
Wouldn't properly rehydrating and proofing your yeast increase the cell-count (before it is pitched)? I.e. wouldn't the numbers in the maths quoted earlier in the thread need to be adjusted for the cell count when the mixture is pitched?
According to Palmer, the rehydrated yeast is pitched_ before _pouring in the cooled wort. There is no recommendation to mix. I assume by doing things in this order the yeast is well mixed with the wort "for free". Funny thing is, almost everywhere else I have seen (this forum included) describes pitching _on top of _the wort. Any reason _not _to follow Palmer's advice?
NB. Fermentation is strong and vigorous with nice Krausen. :icon_chickcheers: Re-reading Palmer's instructions I also just realised I only used one packet of US-05....


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## felten (4/1/11)

Have a read of this http://koehlerbeer.com/2008/06/07/rehydrat...r-clayton-cone/ (just noticed this was already posted above, whoops)

It's best to follow the manufacturers specific instructions for each yeast strain though.


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## cKc (4/1/11)

felten said:


> Have a read of this http://koehlerbeer.com/2008/06/07/rehydrat...r-clayton-cone/
> 
> It's best to follow the manufacturers specific instructions for each yeast strain though.



Cool - thanks. So that answers the question of potential damage done by rehydrating too hot. Since the Safale specs state 27C +/- 3C I guess I was up to 10C too hot! So fermentation is likely to take a bit longer.

Any comments on the other questions? :icon_cheers: 



> _Answered._
> Wouldn't properly rehydrating and proofing your yeast increase the cell-count (before it is pitched)? I.e. wouldn't the numbers in the maths quoted earlier in the thread need to be adjusted for the cell count when the mixture is pitched?
> According to Palmer, the rehydrated yeast is pitched_ before _pouring in the cooled wort. There is no recommendation to mix. I assume by doing things in this order the yeast is well mixed with the wort "for free". Funny thing is, almost everywhere else I have seen (this forum included) describes pitching _on top of _the wort. Any reason _not _to follow Palmer's advice?


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## Ross (4/1/11)

None at all - either way works fine.

cheers Ross


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## felten (4/1/11)

> # Wouldn't properly rehydrating and proofing your yeast increase the cell-count (before it is pitched)? I.e. wouldn't the numbers in the maths quoted earlier in the thread need to be adjusted for the cell count when the mixture is pitched?


Yes, with proper rehydration you can recover 100% of the yeast cells, as for the optimum pitching rate I would check with the mrmalty calculator.



> # According to Palmer, the rehydrated yeast is pitched before pouring in the cooled wort. There is no recommendation to mix. I assume by doing things in this order the yeast is well mixed with the wort "for free". Funny thing is, almost everywhere else I have seen (this forum included) describes pitching on top of the wort. Any reason not to follow Palmer's advice?


I'm don't think before or after would make a difference. Whichever way you do it, it's recommended to get your yeast to within 8c or less before pitching, otherwise you may shock the yeast.


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## cKc (4/1/11)

Great - appreciate the quick responses.

Main takeaway from me is _if _I bother to rehydrate next time I should make sure I do it properly, according to specs. Otherwise my attempts may in fact result in a lower cell count going in the fermenter than if I'd just dry pitched anyway <_< 

Cheers.


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## The Giant (4/1/11)

Bit of n00b question but what is the benefit of rehydrating yeast?
Is it just so ur yeast cells work better/more effectively?

Reading this I assume its easy as putting yeast into the correct temperature water and letting it settle before adding to the wurt?


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## manticle (4/1/11)

Check the first page of the thread for instructions and info on why it can be beneficial.


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## Mattwa (1/9/15)

If anyone stumbles across this topic again and wants to check out the link above from felten, it's moved to https://koehlerbeer.wordpress.com/2008/06/07/rehydrating-dry-yeast-with-dr-clayton-cone/


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