How many don't rehydrate their yeast?

[rhys333]

I rehydrate if I'm doing ~1.050 5 or 6 gallon brews, but lately I'm doing a lot of 4 gallon stove top batches. When using dry yeast on these I just direct pitch without rehydrating.

 

[UndeadFred]

I do rehydrate dry yeast because, even though I know better about being patient for up to 48 hours (on ales), I am a horrible worry wort. If I see it "proof" (foam up) then it's likely good and then I don't worry until the next morning..

I find it interesting though that you lose 50% of viable cells and that somehow matters.. with those cell count numbers I'd be concerned with "orders of magnitude" and not "2"... but I'm an engineer.

If I forgot to rehydrate and I was post chill, I'd probably dry pitch most beers..

Fred

 

[bierhund]

Orders of magnitude would come into play once cell division comes into play. Losing half your cells due to shock will cause the lag phase to take longer. The shock from the high sugar (relative) environment causes heat shock proteins to turn on. This can potentially cause issues in fermentation. I think in a small batch/low gravity beer, these effects are unnoticed because there still is plenty of cells to get the job done. Dry yeast provides the most cells out of all the ways to use yeast. That being said, I would bet that if the yeast was properly rehydrated, it could handle larger batches / higher gravity ales. It would be a neat experiment. I like to think of it like this, "How would I like to be woken up from a deep sleep? Gently with a warm cup of coffee and breakfast cooking or with a pail of ice cold water?" I know which method is going to start my day better lol

 

[kombat]

The problem with not rehydrating dry yeast is the oft quoted study by Chris White stating that direct pitching of dry yeast results in up to 50% reduction in viable cell counts.

I can't find the study. I believe it is just mentioned as empirical data in his book "Yeast". Not a peer revied syudy in a scientific journal but his own unpublished work. I could be wrong.

FYI, the "White" in "White Labs Yeast" is the same White in Chris White. As in, it's his company. I trust his knowledge of yeast.

I always rehydrate. I want to give my beer the best chance possible, and the research suggests if I pitch dry, I'm wasting half my money, so why not rehydrate? It's not that hard.

 

[bob1852]

FYI, the "White" in "White Labs Yeast" is the same White in Chris White. As in, it's his company. I trust his knowledge of yeast.

I always rehydrate. I want to give my beer the best chance possible, and the research suggests if I pitch dry, I'm wasting half my money, so why not rehydrate? It's not that hard.

since they don't sell 1/2 packs, you're not really wasting any money.

 

[Gavin C]

FYI, the "White" in "White Labs Yeast" is the same White in Chris White. As in, it's his company. I trust his knowledge of yeast.

I always rehydrate. I want to give my beer the best chance possible, and the research suggests if I pitch dry, I'm wasting half my money, so why not rehydrate? It's not that hard.

Yeah. I know.

Totally aggree. Simple no effort task, no down side.

I too trust the information from the Chris White book and Chris White himself. I have no reson to question his or it's veracity; not my intent to do so. It's just that to the best of my knowledge, the data is not open to scrutiny. Nor should it have to be of course.

His products speak volumes as to the man's knowledge and skill.

 

[rhys333]

FYI, the "White" in "White Labs Yeast" is the same White in Chris White. As in, it's his company. I trust his knowledge of yeast.

Does White Labs sell dry yeast or just liquid? Financial incentive does sometimes play a role in interpreting data. I'm not arguing its the case, just playing Devil's Advocate.

 

[kombat]

I'm not sure - but his statements in "Yeast" don't claim that liquid yeast is universally superior to dry, but rather simply that sprinkling dry yeast directly into wort can reduce viability by up to 50%. If he were seeking to discredit competition, I'd expect him to take a position that portrays liquid yeast as superior to dry in all cases, rather than simply telling you how to get the most out of your dry yeast (that he doesn't even sell).

 

[rawlus]

I think you can use yeast the way you want, but I also think that if you choose to pitch dry yeast you also forfeit delving into inane detail on other aspects of the brewing process. There's no point in discussing water or malt freshness or temp control if you're taking a kit approach to pitching yeast. Yeast actually make beer. Give them some respect.

 

[Akavango]

I have brewed a few pro batches under contract, S05 was used for 3 of them. The first batch, the yeast was rehydrated and the other 2 dry yeast was dumped into the fermenters. There was no noticeable difference between the batches. Each batches were 2200L and the OG was 1053. They all came down to 1010.

 

[rhys333]

I'm not sure - but his statements in "Yeast" don't claim that liquid yeast is universally superior to dry, but rather simply that sprinkling dry yeast directly into wort can reduce viability by up to 50%. If he were seeking to discredit competition, I'd expect him to take a position that portrays liquid yeast as superior to dry in all cases, rather than simply telling you how to get the most out of your dry yeast (that he doesn't even sell).

You have a point there, but it can have the effect of knocking dry yeast manufacturers down a peg or two. Perception only of course. I don't mean to whack the beehive but its fun to ponder these things.

 

[Venari]

I tend to just sprinkle the dry yeast onto the foam (after splash aerating, there's quite a bit of foam)

Everything seems to turn into beer.

 

[joshesmusica]

You have a point there, but it can have the effect of knocking dry yeast manufacturers down a peg or two. Perception only of course. I don't mean to whack the beehive but its fun to ponder these things.

Completely disagree. Why would it have the effect of knocking them down a peg or two? If you read his advice correctly,

"If you are working with dry yeast, determining how much to pitch is relatively easy. Most dry yeast contains about 7 billion to 20 billion cells per gram, depending on the cell size and other nonyeast material, but that is not the number of viable cells per gram you will have once you rehydrate yeast. That depends on a number of factors, such as storage and rehydration techniques. Find out from your supplier how many viable cells per gram you can expect (which might be as low as 5 billion), then simply divide the number of cells needs by the number of viable cells, and you will know the weight in grams of dry yeast need. Of course, this assumes all the yeast is active and that you properly rehydrate it following manufacturer's recommendations before pitching. Failure to rehydrate dry yeast properly will result in the death of approximately half the cells."

This is an aside when talking about how to figure out your viable cell count in slurries and in liquid yeast vials. He goes into great detail about how to determine that, and talks about some less complicated ways to figure it out, but for the most part shows how complex it can really be. Then he states how easy it is to figure out the cell count for dry yeast. Which would make it sound more like an endorsement for using dry yeast because you know how much yeast to expect in the pack. Never does he say, "Oh but then with dry yeast you have to take the extra 10-15 minutes to rehydrate it. How lame is that?" He simply says, follow the manufacturer's advice in how to rehydrate properly, and you'll easily have the amount of viable yeast cells you're expecting.

He has absolutely no financial incentive to convince people to rehydrate. In fact, quite the opposite. If he finds out that people are thinking they're pitching approximately 200b cells, and in fact his studies are showing that 100b of those are dying off by dry-pitching, he has EVERY incentive to keep his mouth shut. He should want people to keep under-pitching, in the hopes that they will produce lower quality beer, and he can then point to exact studies about his own yeast and how many viable cells to expect, and how much more reliable his yeast is compared to dry yeast.

It helps to play the devil's advocate with actual logical arguments.

As far as my opinion on the matter, I'll just reiterate what others have said:
1) Even Safale says you can do both. Which leads me to believe that they likely know something about rehydration, but want to make the ease-of-use of their product appealing.
2) Anecdotal evidence of people under-pitching, yet still creating good beer will never trump evidence from the guy who runs his own yeast lab. Never.
3) It's so simple and easy, I just don't see why people would skip it.

 

[RM-MN]

Orders of magnitude would come into play once cell division comes into play. Losing half your cells due to shock will cause the lag phase to take longer. The shock from the high sugar (relative) environment causes heat shock proteins to turn on. This can potentially cause issues in fermentation. I think in a small batch/low gravity beer, these effects are unnoticed because there still is plenty of cells to get the job done. Dry yeast provides the most cells out of all the ways to use yeast. That being said, I would bet that if the yeast was properly rehydrated, it could handle larger batches / higher gravity ales. It would be a neat experiment. I like to think of it like this, "How would I like to be woken up from a deep sleep? Gently with a warm cup of coffee and breakfast cooking or with a pail of ice cold water?" I know which method is going to start my day better lol

Why will this cause the lag time to be any more than the time it takes for the yeast cells to reproduce, thus doubling the amount of cells. It would seem like the difference in time would be a matter of minutes rather than hours.

 

[UndeadFred]

Why will this cause the lag time to be any more than the time it takes for the yeast cells to reproduce, thus doubling the amount of cells. It would seem like the difference in time would be a matter of minutes rather than hours.

You got it. I took particular interest in modern physics in college as an engineer and 2x is exactly one cell reproduction. Yeast acts a lot like quantum physics... (But yeah. It is observable, I get that) If the dry pitch causes all or a lot of mutants I would say that is an issue. But clearly almost exactly no one has ever said a dry pitched dry yeast beer tastes significantly worse.. So.. I am thinking.. Overall.. Meh.. I still like seeing a proof though..

Fred

 

[bierhund]

Why will this cause the lag time to be any more than the time it takes for the yeast cells to reproduce, thus doubling the amount of cells. It would seem like the difference in time would be a matter of minutes rather than hours.

That's under the assumption that the yeast are healthy and have a perfect doubling reproduction event. The shock creates unhealthy yeast and wort though delicious is not technically considered a perfect environment.

 

[normonster]

Damn I better start reading that Yeast book since I bought it.

 

[bierhund]

Damn I better start reading that Yeast book since I bought it.

Probably one of the best books in the series. Very useful information

 

[cjbalough]

So, for the folks that argue against secondary because of the risks of infection, do you argue not to rehydrate for the same? For what it's worth, I'm a relative rookie (entering my third year of brewing) and have done it both ways with success, but I do tend to prefer liquid yeast as i think the bad batches I've made have have all been with dry yeast, the worst 2 were Nottingham rehydrated with properly boiled then cooled water.

 

[rhys333]

Oh dear, I did whack the beehive.

 

[normonster]

Oh dear, I did whack the beehive.

Hive-whacker!

 

[moreb33rplz]

I'm still not convinced. He doesn't cite any studies or anything, he just says 'it will kill half the yeast'.

I know he knows more than me, but something that definitive should have some evidence you can point at.

 

[bierhund]

Wikipedia provides a possible explanation to why the yeast die. Depending on what reproductive state the yeast are in (haploid vs diploid) will greatly affect their ability to handle stressful environments.

https://en.m.wikipedia.org/wiki/Saccharomyces_cerevisiae

 

[rhys333]

You got it. I took particular interest in modern physics in college as an engineer and 2x is exactly one cell reproduction. Yeast acts a lot like quantum physics... (But yeah. It is observable, I get that) If the dry pitch causes all or a lot of mutants I would say that is an issue. But clearly almost exactly no one has ever said a dry pitched dry yeast beer tastes significantly worse.. So.. I am thinking.. Overall.. Meh.. I still like seeing a proof though..

Fred

Amen brother.

 

[edues]

I never did and I never had a problem. Sprinkle mix n go.

 

[jwalk4]

When I began brewing, I pitched dry because it was simple. After some long lagtimes and many google searches like "Why isn't my wort fermenting?" I started rehydrating and now my beers take off like a shot!

I am converted. Rehydrating is even easier and more satisfying than rdwahahb.

 

[Pkrd]

I'm speculating the US-05 rehydration instruction let you know that you can dry pitch if you really want too because otherwise everyone would buy the other brand. Certainly doesn't mean its best practice.

Also, rehydration speeds up brew night because you don't have to wait for half an hour after you pitch.

Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 27°c ± 3°C (80°F ± 6°F). Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.
Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). 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, then mix the wort using aeration or by wort addition.

 

[joshesmusica]

I'm still not convinced. He doesn't cite any studies or anything, he just says 'it will kill half the yeast'.

I know he knows more than me, but something that definitive should have some evidence you can point at.

Ok, good lord you guys are picky with your scientific data to back facts up all the time!

http://seanterrill.com/2011/04/01/dry-yeast-viability/

https://bkyeast.wordpress.com/2013/03/13/more-on-yeast-rehydration/

 

[Gavin C]

Thanks for the interesting links @Joshesmusica

Much appreciated

 

[kombat]

I'm still not convinced. He doesn't cite any studies or anything, he just says 'it will kill half the yeast'.

I know he knows more than me, but something that definitive should have some evidence you can point at.

Read "Yeast." According to biologists much smarter than me, the problem is that until the yeast cells are rehydrated, they're unable to regulate the amount of sugars passing across their membrane, which can lead to autolysis. Once they're rehydrated with plain water, they're much better able to regulate sugar uptake across their membrane.

Or something like that. I trust the guy with the multi-million dollar yeast company and the Ph.D.