Re-Hydrating Yeast

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mangine77

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Ok. So I've always been a just open the packet of dry yeast and pour it in guy. I've NEVER once had a problem.

Yesterday for the second time ever I rehydrated the yeast, 24 hours later, no fermentation. So both times that I've rehydrated, I've gotten no fermentation within 24 hours. The first time, I never got fermentation and I had to re-pitch after 2.5 days.

Now, I know it's only been 24 hours, but I always have something going before now, so of course it makes me nervous.

So, here's the question. I did re-hydrate my yeast pretty early in the brew day. I boiled 1 cup of water, let it cool to 95 degrees and sprinkled in the yeast. Covered with a sanitized lid. Right before I pitched, I swirled it up with a sanitized spoon, and yes I aerated the wort.

I've since learned that most people do this about 15 minutes before pitching. I did this about 90 minutes before pitching.

Will this make a difference? Is this why I'm not seeing fermentation yet?? Does this extra time of the yeast sitting in the water hurt something?

When would you re-pitch?
 
I rehydrate all the time, and the closer to the pitch time, the better control over the temperature. Also, it ensures your dry yeast is activated. I never have proofed the yeast, but have found rehydrating to give me some peace of mind.

From what I understand, the yeast slurry needs to be pretty on target with the temperature of the wort. So if you are pitching the yeast at a different temp than the wort, the yeast might get shocked.

I would repitch just to be safe.

Good luck!:mug:
 
You really do want to rehydrate then pitch immediately, although 90 mins shouldn't be long enough to do kill your yeast and your fermentation. Double-check that you are actually rehydrating at the temperature recommended by the yeast manufacturer. If your thermometer is out, you might be frying your yeast. Otherwise, perhaps it is just a bad coincidence?
 
But do you think there is still a chance it will take off?

I also don't have any other yeast laying around. I know that I should.

Homebrew shop is closed today. That means if it doesn't take off by tomorrow morning, it will be at least 48 hours lagtime before I get to repitch.

Should I even bother re-pitching at that point, or dump it???

I've read the chances of a beer coming out good after 48 hours and then re-pitching is rare.

Do you agree?
 
... I boiled 1 cup of water, let it cool to 95 degrees and sprinkled in the yeast. Covered with a sanitized lid. ...

It sounds to me like you are rehydrating the yeast with water that is just too hot. I rehydrate every brew and fermentation always takes off fast (< 12 hours).

It can be instructional to look up the manufacturers recommended rehydrating practices. For example, these are the instructions for rehydrating Fermentis SafAle US-05:

"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."

And these are the instructions for rehydrating Nottingham:

"Sprinkle the yeast on the surface of 10 times its weight of clean, sterilized (boiled) water at 30&#8211;35°C. 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&#8211;35°C. Then adjust temperature to that of the wort and inoculate without delay."

There aren't many differences, but there are some, including temperature range and whether to stir or not during the first 15-30 minutes
 
I was just following the instructions from Jamil's book and I didn't think to look at specific yeast directions.

So what about the rest of my questions about should I even bother to re-pitch?

Is there anything I can do during the next 24 hours that I have to wait for my homebrew shop to open, that will help?

I have a real turn-off to re-hydrating now. I'm 0-2. I've probably brewed 40 batches by just sprinking the yeast on top, and I've never had an issue. I'm not convinced it makes that much of a difference.

Does anyone else out there still just pitch it dry?
 
What temperature is the water you are rehydrating with?

I followed the advice from the Palmer book that said any dry yeast can be rehydrated from 90-105 degrees. I rehydrated at 95, so I thought that would be good.
 
95F is totally fine.

100dF is actually the ideal temperature for yeast to adsorb water into their membranes...

And Safale actually recommends about an hour of rehydrating prior to pitching.

"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. 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."

I have done this twice now (100dF, 30 mins of sitting, then 30 mins of stirring, then pitch) and have had great results. Safale says to use about 80dF (± 5F) water, but you're totally fine at 95dF.


EDIT: Just thought of something. You didn't use RO water or distilled water, did you? You want to make sure there are some minerals in the water too. I used tap water that has been boiled and then cooled.
 
I gotta say I've had a similar experience as the original poster. It's actually uncanny--I was going to post this exact topic this evening.

I brewed a foreign extra stout on Saturday and although I usually direct-pitch when I use dry yeast, this time I figured I'd rehydrate per the recommendation in "Brewing Classic Styles" by Zainasheff & Palmer (I was using a variation of the recipe on p.171).

About halfway through the boil, I boiled about a cup of tap water for 5 minutes, covered it, and let it cool. After the wort was finished boiling, I started the wort chilling process and checked on my cup of water. It was down to 91°F so I sprinkled 11g of Nottingham and re-covered it. Once the wort was down to about 75°F I checked on the yeast-water, and the yeast was thoroughly wet-out, forming a uniform layer of sediment at the bottom of the pan. I stirred up the yeast into a slurry and pitched it into the cooled and oxygenated wort. There couldn't have been more than about 10°F temperature difference between the slurry and the wort, so I have no reason to suspect the yeast cells were shocked. I pitched at 6PM Saturday.

By noon on Sunday, I expected fermentation to be well underway (my last 10 batches or so have all taken off in a matter of a few hours and most have finished primary fermentation within 48 hours.) But, now at 18 hours after pitching, there was no activity whatsoever. The wort was sitting at 64°F with no krauesen. I direct-pitched another 11g of dry Nottingham, and by late evening, fermentation was underway.

I haven't given up on re-hydrating, but I'm open to suggestions before I do it again. I actually figured I might dip-out a cup of wort during the boil and let it cool to a suitable temperature and use it for re-hydrating, rather than boiling tap water. But now I see in this thread that the use of wort is not recommended. Any ideas on why?

I'll have to look back through my notes from past batches, but I'm quite certain I've re-hydrated dry yeast in a similar manner a couple times before and everything worked out fine. Puzzling, indeed. To mangine77, I'd still pitch new yeast. Even at 48 hours later, I think you can still hold out some hope that you will be able to make decent beer. And for the future, you should always have a few packets of common dry yeast on-hand for such emergencies. I make it a point to keep US-05, Nottingham, S-33, S-04, & T-58 hanging around in the fridge.
 
I checked on the yeast-water, and the yeast was thoroughly wet-out, forming a uniform layer of sediment at the bottom of the pan.
That's strange. Anytime I have rehydrated dry yeast, it mostly floats on top and foams up after about 15 mins. Did it all really sink to the bottom and just sit there?
 
At first, it floats and spreads out evenly across the top of the water. This is always what happens when I pitch yeast. But once it's wet-out, the yeast grains break up and "dissolve" into the water or wort. (I use the word "dissolve" loosely because I think of it as more of a suspension.) At any rate, when I checked on the yeast-water later on, the majority of the yeast was settled to the bottom.
 
I've tested the impact of rehydration and it's valid from the point of preserving the max number of cells. Is it possible your thermometer is off and you're pitching into 110F water?
 
I've tested the impact of rehydration and it's valid from the point of preserving the max number of cells. Is it possible your thermometer is off and you're pitching into 110F water?

Well, that's what I'm starting to think. So, it's been 48 hours and nothing is happening. I took a real quick peek inside, nothin.

I'm just sitting here waiting for 9am to roll around, so I can go to the HBS and pick up another pack of S-05.

What do you think the odds are that this still turns out to be a decent beer and doesn't get contaminated with all this lagtime??
 
In my case, I used a digital probe thermometer for both the water that re-hydrated the yeast, and the wort that was chilling. The reading I got with the digital probe thermometer when I finished chilling the wort agreed with the reading on the liquid crystal thermometer I got a few minutes later after racking the wort to the fermenter. So there was one check to make sure the thermometer wasn't flaking out on me. It's still possible that something was amiss, but I think it's unlikely that my probe thermometer was way off.

mangine77, just repitch and think positive. :) You've already done all the hard work. Dropping in another $3 worth of yeast with even an outside chance of saving the effort and cost of brewing a new batch is a no-brainer. Yeah, your chances of infection have gone up a bit, but if your process was fairly sanitary you could still be looking at good clean wort that's just begging to throw a yeast-party.
 
I forgot to boil my water first last on my last batch, do you think this will be a big deal? Water from the tap must be pretty sanitary right?
 
I forgot to boil my water first last on my last batch, do you think this will be a big deal? Water from the tap must be pretty sanitary right?

I used to top off with straight tap water with no problem. If the yeast take off, I don't see a problem. Although it still is ideal to use sterile water.
 
I screwed up one batch. I hydrated the yeast according to instructions, but I used warm tap water. I found out later my tap water (well) sucks. The beer is the worst I have made. Still drinkable, but not good. The next batch I just sprinkled the yeast on the wort and had no problems. Good beer.

I generally use liquid yeast with a starter, but tried the new dry stuff.

Now I wash and save the liquid yeast. I just have better luck.

David :)
 
"I found out later my tap water (well) sucks. The beer is the worst I have made. Still drinkable, but not good. The next batch I just sprinkled the yeast on the wort and had no problems. Good beer."

Probably it was using warm tap water. THe guy who said it should be 90f's = 32*c!!! that is WAY too hot!!

I always rehydrate with the coldest water possible (5-10*c). At pitching the fermenter should be at 18-25 *c. alot lower i think for lagers, but i only do ales.

Sources: various beer guides, kits, and pamphlets.

If you have yeast that activates at 32*c then it is yeast for bread not beer. They are different. Or so i was told.

i was interested in the guy who said that it should be as close to the temp of the wort as possible. Usually i pitch at 23*c or so, but i have never had a problem. I suspect, as with most things with this hobby, it is hard to screw up.
 
Probably it was using warm tap water. THe guy who said it should be 90f's = 32*c!!! that is WAY too hot!!

I always rehydrate with the coldest water possible (5-10*c). At pitching the fermenter should be at 18-25 *c. alot lower i think for lagers, but i only do ales.

Sources: various beer guides, kits, and pamphlets.

If you have yeast that activates at 32*c then it is yeast for bread not beer. They are different. Or so i was told.

Actually, 32C is just about perfect for Nottingham, as per the company's data sheet. And it's only a little warm for the Safale US-05, as per their data sheet.
 

An interesting stance he takes on rehydrating yeast. I would like to know where he gets his information since I've never seen a manufacturer recommend this. I guess it could be argued that dry pitching straight into the fermenter would be rehydrating in wort. But I've seen several references, both from the yeast manufacturers themselves and other people far more experienced on the matter than myself, state that it can be detrimental to the yeast to be rehydrated in wort.

This link has Dr Clayton Cone of Lallemand Lab responding to a question from a homebrew shop owner about rehydrating yeast that says almost the exact opposite.

I personally say do whatever works for you, it's your beer, but for those who do want to rehydrate, I'd prefer them to have the best advice possible.
 
Actually, 32C is just about perfect for Nottingham, as per the company's [Literature]

Well, did you read that pdf? You have to cool it down in a very laborious way or it forms and i quote
"Attemperate in steps at 5- minute intervals of 10*c to the temperature of the wort. Do not allow attemperation to be carried out by natural heat loss" " temperature shock at greater than 10*c will cause formation of petite mutants> leading to long term incomplete fermentation"
Emphasis mine.


Mutants dude! that tells you something right there!

Besides, this is probably some pro grade yeast what does have a higher than normal tolerance for temp. The pdf says it eventually does its job at the lower temp of the wort. Or at least I assume it is lower temperature, as i dont think its recommended to ferment at 35*c !


The other gentlemens link with some pretty molecules is a bit more convincing however could be completely false and just backed up by pointless images. Most beer kits do say sprinkle it but i always read it was bad.

I am sure you really cant go wrong with modern brewing, if you picture the tools and ingredients that people had to work with, hundreds to tens of thousands of years ago. Its easy to see how we are much better off. :tank:
 
I don't use tap water ever. Use spring water that is bottled, when I re hydrate yeast it always starts fermenting later because the yeast starts in the bottom instead of the top.(more air on the top). If you aerated your wort you shouldn't have a problem. If you didn't, you may just have a slow fermentation process. Remember, just because you aren't seeing any activity in your air lock, doesn't mean it isn't fermenting. Take a hydrometer reading and see if it's going anywhere. I'm brewing an Irish stout that didnt start bubbling til 24 hours or more later. now it is bubbling out of control for the last 2 days.
 
My tap water is from a glacier. Its good you brought this back up so I can post an update. After posting this some months ago, I stopped re-hydrating the yeast. This is partly to save some time on brewing day, however I have not noticed any difference in sugar absorption in the fermented beer either. (which might not be as scientific as a hydrometer, but its less complicated, messy and more delicious). I am not sure of any other negative effects from not rehydrating.

When I did rehydrate, I stirred it around the same as I do now. Although really, if you picture it like mold or something, the yeast is im sure going to munch munch munch till its all munched away! Although I dont have any science for that.
 

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