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crazyboy · 04-14-2009, 02:14 AM

There are many different strains of yeast available some produce more alcohol others less, some produce esters and others do not. How can a homebrewer go about creating a strain of yeast unique from a store bought strain?

If I wanted a super yeast like the one used to brew utopias could I pitch Nottingham into a unusually high sugar wort, harvest the living yeast and repeat until I get the strongest ones?

Boulderbrewer · 04-14-2009, 03:06 AM

It sounds like you are on the right track. You would be looking for a yeast that will withstand high alcohol levels, but you want one that give you high attenuation also.

menschmaschine · 04-14-2009, 01:19 PM

In theory, yes. It's similar to selective breeding. This can take a long time though and many yeast generations. Didn't it take Sam Adams like 15 years to get the yeast for Utopias? To do it right, you'd also need some lab equipment to culture and isolate yeast strains.

**pjj2ba** · 04-14-2009, 03:01 PM

Yeast sex. Yeast have to come across another of a different mating type to have sex. In our fermentoers, they are strictly doing it with themselves. I recall seeing a scientific paper (available online - might take some searching) on common brewing strains that had a table that gave the mating type for them. Mix two of the opposite kind together and bingo, new varieties. That is the easy part. All of the offspring produced, are going to be, just like with us, different. The trick then is to select for the ones with the characters you want.

As Mensch said, lab equipment would certainly be handy. Or if you just are into it for fun, go for it. After your yeast have sex, boil up 5 gal. batch and divide it into 5 1 gal. containers for fermentation. Bottle them up, and then taste. Keep the yeast from the one you like best. Do the same thing again, this time dividing the one you liked into 5 again. Or whatever you want, 2, 3 gal. etc batches. Keep the yeast from the batch you like best. And so on, and so on.

menschmaschine · 04-14-2009, 03:39 PM

Quote:

Originally Posted by pjj2ba

Yeast have to come across another of a different mating type to have sex. In our fermentoers, they are strictly doing it with themselves. I recall seeing a scientific paper (available online - might take some searching) on common brewing strains that had a table that gave the mating type for them. Mix two of the opposite kind together and bingo, new varieties. That is the easy part. All of the offspring produced, are going to be, just like with us, different. The trick then is to select for the ones with the characters you want.

Not that I know all that much about yeast genetics, but just from my general biology background, aren't there other contributers to selecting yeast strains? IOW, some yeast cells within a strain may have or develop better resistance to alcohol or exhibit various levels of ester production, regardless of their reproduction. Each individual brewhouse may, over time, affect a yeast strain due to wort chemistry (lauter techniques, etc.), aeration techniques, etc.

I'm just reminded of a paper I did in college on benthic invertebrates (in this case midges) and the effects of acid mine drainage on them... whether they developed resistance to various parameters of acid mine drainage pollution genetically (breeding/mutations) or if they developed certain tolerances individually.

**rocketman768** · 04-14-2009, 07:32 PM

Quote:

Originally Posted by crazyboy

There are many different strains of yeast available some produce more alcohol others less, some produce esters and others do not. How can a homebrewer go about creating a strain of yeast unique from a store bought strain?

If I wanted a super yeast like the one used to brew utopias could I pitch Nottingham into a unusually high sugar wort, harvest the living yeast and repeat until I get the strongest ones?

Or you could artificially stress your yeast. It would probably require less time and resources. Place them in a 10% ethanol solution and propagate the survivors (for example).

FLO1 is a variable green beard gene that drives bi...[Cell. 2008] - PubMed Result

Damonic · 04-14-2009, 08:25 PM

In all honesty I'd just leave it to the pros with expensive machinery and spend you time brewing beer!

menschmaschine · 04-14-2009, 08:35 PM

Quote:

Originally Posted by Damonic

In all honesty I'd just leave it to the pros with expensive machinery and spend you time brewing beer!

That's not in the spirit of the Brew Science Forum!

Damonic · 04-14-2009, 08:45 PM

Sorry! Sorry! Mutate away my friends... mutate away!

crazyboy · 04-14-2009, 10:22 PM

Quote:

Originally Posted by rocketman768

Or you could artificially stress your yeast. It would probably require less time and resources. Place them in a 10% ethanol solution and propagate the survivors.

This is the exact conclusion I came to earlier today! I think I could take some white labs super high gravity yeast which can take up to 25% alcohol pitch it in 15% alcohol repropagate, pitch into 20% repropagate 25% etc...

As far as lab equipment goes my other hobby is chemistry so I have beakers, flasks, a heating mantle, distillation apparatus, thermometers, graduated cylinders and a microscope (800x).