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**agroff383** · 09-01-2009, 01:14 AM

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.

Suthrncomfrt1884 · 09-01-2009, 01:49 AM

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.

hexmonkey · 09-01-2009, 05:48 AM

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.

kanzimonson · 09-01-2009, 08:39 PM

Quote:

Originally Posted by hexmonkey

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.

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?

Schizosaccharomyces · 05-12-2011, 10:28 PM

Quote:

Originally Posted by Suthrncomfrt1884

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).

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/

JonK331 · 05-12-2011, 10:35 PM

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

hexmonkey · 05-13-2011, 01:49 AM

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

blackstrat5 · 05-13-2011, 02:59 AM

Quote:

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

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

Noobrew · 05-13-2011, 03:03 AM

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

**bwomp313** · 05-13-2011, 03:50 AM

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?