Breeding yeast?

Does anyone know if breeding yeast is possible, in a non scientific way…

If i was to make a beer with say one pack of us 05 and one pack of us 04. and use that yeast cake for several generation would i have a yeast strain that is unique or would it just be half us 05 and half us 04? Granted im not going to go buy lab equipment and get crazy but if its that easy i think it’d be soemthing cool to experiment with.

[quote=“beerme11”]Does anyone know if breeding yeast is possible, in a non scientific way…

If i was to make a beer with say one pack of us 05 and one pack of us 04. and use that yeast cake for several generation would i have a yeast strain that is unique or would it just be half us 05 and half us 04? Granted im not going to go buy lab equipment and get crazy but if its that easy i think it’d be soemthing cool to experiment with.[/quote]

When you do that the results are completely unpredictable, especially if you reuse it. And you wouldn’t be creating a “new” strain of yeast.

[quote=“Denny”][quote=“beerme11”]Does anyone know if breeding yeast is possible, in a non scientific way…

If i was to make a beer with say one pack of us 05 and one pack of us 04. and use that yeast cake for several generation would i have a yeast strain that is unique or would it just be half us 05 and half us 04? Granted im not going to go buy lab equipment and get crazy but if its that easy i think it’d be soemthing cool to experiment with.[/quote]

When you do that the results are completely unpredictable, especially if you reuse it. And you wouldn’t be creating a “new” strain of yeast.[/quote]

Got ya. Just a thought, figured it couldn’t be that easy. You have wyeast 1450 Denny’s favorite, how did you go about developing that? Not in detail or anything im just curious on how creating a strain would be done.

[quote=“beerme11”][quote=“Denny”][quote=“beerme11”]Does anyone know if breeding yeast is possible, in a non scientific way…

If i was to make a beer with say one pack of us 05 and one pack of us 04. and use that yeast cake for several generation would i have a yeast strain that is unique or would it just be half us 05 and half us 04? Granted im not going to go buy lab equipment and get crazy but if its that easy i think it’d be soemthing cool to experiment with.[/quote]

When you do that the results are completely unpredictable, especially if you reuse it. And you wouldn’t be creating a “new” strain of yeast.[/quote]

Got ya. Just a thought, figured it couldn’t be that easy. You have wyeast 1450 Denny’s favorite, how did you go about developing that? Not in detail or anything im just curious on how creating a strain would be done.[/quote]

I didn’t develop it, I discovered it in the yeast banks of a company that’s now out of business. You had to buy slants and culture it yourself. When they went out if business I still had some slants in my fridge. I convinced Dave Logsdon if Wyeast to use my slants to build up a stock for Wyeast to sell in smackpacks.

While I agree that the results would be unpredictable I don’t think it’s a waste of time for anyone who is interested. The real problem, a far as I’m concerned, it’s numbers. At the end of several generations you would have billions ofyour original yeast and some new yeast. Without any selection, there’s no reason for your hybrid yeast to dominate the culture. however you could think of some ways to select some traits that you want. Flocculation is probably the easiest.

Yeast don’t cross breed, so one type of yeast being in the presence of another type won’t affect it. You could still have interesting results using two strains and see if you like what you get.

Keep in mind if you reuse the slurry, one strain will likely dominate and you won’t have a 50/50 split anymore.

I’ve found that if you really want to use 2 different yeasts it works much better to split the batch, ferment each half with a different yeast, then blend them.

Yes, yeast do “cross breed”, though some strains may not.

this. otherwise one will dominate over the other, IME.

Yup. Though if that happens they won’t all result in the creation of some uniform third strain, but rather thousands of new yeasts each different from all others. So you’ll have your two main strains there and a ton of single cell strains who’s impact on flavor will not be noticeable.

On the other hand, if you can introduce a selection, you could potentially enrich for novel yeast strains which could then be isolated by streaking, which is pretty straightforward. For instance, mix a high-flocculating ale strain and a weizen strain in a small tube. After a day (?) of fermentation, when sugars are just being exhausted, remove the supernatant (all the yeast in suspension). Add fresh wort and repeat several times. Streak out to isolate single clones. You may have enriched for high flocculating yeast which may have some Hefe genes. You should be able to pick out some clones that have different aromas that you can pick out by culturing in small tubes from single colonies. If you’re lucky.

Of course if you really want to do it, then you would want to start with single cells of each strain, test for mating type (by watching them schmoo towards reference strains under the microscope), and cross the appropriate strains.

Yeast rely on asexual reproduction - there is no breeding involved

Beaver is right. Actually there is a lot of sex involved with yeast. Happens all the time.
Brewer yeast also form spores, which adds a whole new level of sexual reproduction into the picture.
Just because they prefer budding doesn’t mean they exclusively reproduce that way.

Theoretically, sexual reproduction could happen in fermenting wort. Practically speaking, budding is the only method you’ll encounter in a homebrewing environment

Wrong. I haven’t bothered looking at my yeast during fermentation, but post fermentation I have found plenty of spore formation.

From the wikipedia article:

In general, under high stress conditions like nutrient starvation, haploid cells will die; under the same conditions, however, diploid cells can undergo sporulation, entering sexual reproduction (meiosis) and producing a variety of haploid spores, which can go on to mate (conjugate), reforming the diploid.

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