Any good reading on yeast science? I have questions

Hey all, I just want to know a few specifics about yeast itself. How does a yeast manufacturer say, "Hey let's make a new strain". What all goes into that? What is the intrinsic differences between Nottingham and S-04 and a wheat beer yeast? They must still be very similar since they are all under the general term of yeast. I want to know how this works. It is very interesting but how did they arrive at a new kind of yeast if they only had a certain amount of varieties before.

Basically what I want to know is how do you make a new yeast strain and can a homebrewer do it to tailor make their own strain of yeast.

Lots of homebrewers use a custom strain for all of their beers. Sometimes it's just a mixure of a few current strains, and sometimes they culture it themselves by letting a petri dish sit out for a few months (very basic explaination). BYO magazine had a great issue this past month. It had 3-4 articles all about yeast. I suggest picking it up if you're interested in yeast biology and/or culturing your own.

According to the Phaff Yeast Culture Collection, of UC Davis, they've banked over 6,000 known yeast strains. A yeast company like White Labs probably only needs to take one from that 6,000 and call it "new".

As I understand it, if you want to select for a specific mutation, you just need to induce a particular stress that you want the yeast to be tolerant to. For example, if you brew/wash/reuse an ale yeast over the course of many batches and consistently ferment it on the lower end of its range, you'll eventually wind up with a mutation of that strain that ferments exceptionally well at those temps.

There was a podcast on The Brewing Network that talked about this, I think it was the "Yeast Washing" podcast of Brew Strong.

hexmonkey said:

if you brew/wash/reuse an ale yeast over the course of many batches and consistently ferment it on the lower end of its range, you'll eventually wind up with a mutation of that strain that ferments exceptionally well at those temps.

There was a podcast on The Brewing Network that talked about this, I think it was the "Yeast Washing" podcast of Brew Strong.

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I recently listened to the Brew Strong Yeast Washing podcast and came away with a question about the same topic: At one point, Jamil made a comment that you wouldn't want to continually save yeast from the upper sediment because it's less flocculant than the yeast in the middle layer. If you continued saving this upper layer of yeast, you might end up with a strain that's very highly attenuative with very low flocculation. Makes sense to me.

My question is, aren't you always going to be saving a little bit of less flocculant yeast? I mean, if you're collecting from the primary and the beer hasn't had a long time to settle, these less flocculant yeast will be in the minority, but they're not statistically insignificant. Anybody else stay up at night wondering these things?

Suthrncomfrt1884 said:

Lots of homebrewers use a custom strain for all of their beers. Sometimes it's just a mixure of a few current strains, and sometimes they culture it themselves by letting a petri dish sit out for a few months (very basic explaination).

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If it is a mix of strains then it would not be a custom strain, it would be a custom blend.
Manufacturer's don't "make" new strains. They either acquire a sample from elsewhere, make a master slant, and then propagate (WL001/WY1056 are the same "Chico" strain from the same brewery) or find/develop a mutant from an already existing strain. The mutant strain then has to be developed further through stressing/coaxing to make sure that it is a stable mutant with consistent expression of the desired trait. It is possible to do this at home (Cry Havoc) but the chances of coming up with a stable mutant outside of laboratory conditions is not very likely unless you are willing to invest a lot of time and money.
If you really want to get into some reading on it check out this review:
http://www.springerlink.com/content/e6168770225h0v12/

The new yeast book by jamil Z. and Chris White (White Labs) is great.

LOL zombie topic rising from the dead after almost 2 years!

The new yeast book by jamil Z. and Chris White (White Labs) is great.

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Absolutely...That book has become a guide to me.

New brewer only slightly less new baker. Anyone use the same strain for both? How do I look into keeping my yeast

So then this makes me want to thread jack and ask a question. Everything I know about yeast I've read and learned from others so I'm really not a microbiologist or anything. (Also buzzed so that may not help) When people say that you should only reuse washed yeast for 5 generations or so because of the mutation, if you continue to use it after that will it be "bad" meaning putting out off flavors or fermenting slowly, whatever? Or does that just mean that it'll no longer be the same strain?

Schizosaccharomyces said:

If it is a mix of strains then it would not be a custom strain, it would be a custom blend.
Manufacturer's don't "make" new strains. They either acquire a sample from elsewhere, make a master slant, and then propagate (WL001/WY1056 are the same "Chico" strain from the same brewery) or find/develop a mutant from an already existing strain. The mutant strain then has to be developed further through stressing/coaxing to make sure that it is a stable mutant with consistent expression of the desired trait. It is possible to do this at home (Cry Havoc) but the chances of coming up with a stable mutant outside of laboratory conditions is not very likely unless you are willing to invest a lot of time and money.
If you really want to get into some reading on it check out this review:
http://www.springerlink.com/content/e6168770225h0v12/

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Custom strain...custom blend...all the same to me. I try to make my answers in this site as simple as possible since most homebrewers aren't biology majors.

http://www.yeastgenome.org/

http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae/

Noobrew said:

New brewer only slightly less new baker. Anyone use the same strain for both? How do I look into keeping my yeast

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I have never heard of anybody using a beer specific strain of yeast for baking but it would make sense since bakers and brewers yeast are both S. cerivisiae, however I do know of a lady who has been making mead and other honey/fruit wines with Fleischmann's for over a decade and is constantly winning awards for her entries. Personally I think it would be kinda cool to use part of a fresh yeast cake to get some dough rising and make some tasty bread.

Glad you mentioned the Fleischmann's... My supplier forgot the yeast when she put my ingrediants together and they closed before I started the boil... Let's see how it goes!

The problem with using Fleischmann's is the amounts of contamination units allowed per package. I don't know what the standard is but I know when testing beer and yeast slurries labs aim for less than 10 colony forming units with 0 preferred. Fleishmanns is cheap because they do not adhere to strict cleanliness standards like brewing yeast producers because baking yeast is made for baking and any contaminates die in the baking process.

Good luck with the Fleischmann's. It will ferment but it will be slow. And the taste will not be right. I did it many many years ago and I learned bread yeast is better for bread. And yeast for beer is better for beer. And there is no real difference in cost.

Taste is ok, won't be using this recipie often for other reasons. Biggest pain about Fleishmans is the low floccuation. I lose about an ounce or two each bottle trying to avoid the dregs. Very carbonated, but could be the recipie too.

Worst case scenario: its better than dumping a batch, but I bought extra beer yeast for the next time I'm in a bind.

Schizosaccharomyces said:

I have never heard of anybody using a beer specific strain of yeast for baking but it would make sense since bakers and brewers yeast are both S. cerivisiae, however I do know of a lady who has been making mead and other honey/fruit wines with Fleischmann's for over a decade and is constantly winning awards for her entries. Personally I think it would be kinda cool to use part of a fresh yeast cake to get some dough rising and make some tasty bread.

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I tried it. Bread came out very dense.

Actually if I would have just RDWHAHB, its getting better every day

kanzimonson said:

. . . . Anybody else stay up at night wondering these things?

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Yes, had to get up at 3 this morning too, my brain is sometimes bothersome.

bwomp313 said:

. . . . . if you continue to use it after that will it be "bad" meaning putting out off flavors or fermenting slowly, whatever? Or does that just mean that it'll no longer be the same strain?

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Possibly all or none of the above, it all depends on how you maintain the yeast, when you harvest it, what temperatures you ferment at, what adjuncts you ferment the brews with, etc, etc.

If someone gets into this, I suggest saving a sample of your initial yeast for propagation after a few generations. Unless of course you are trying to mutate it.

That being said, there are companies (breweries/distilleries) that have maintained a specific strain (or blend) of yeast for 10's of years, maybe 100's. It all depends on the effort you can afford to put into it.

Other interesting info: Some strains come from other strains or blends, for instance, I've read that the Duvel strain (Like white labs WLP570) was isolated from the 20 odd strains in the McEwans yeast (White labs WLP028, Wyeast 1728, etc) at Moortgarts in the 1940s I believe