Does the same strain of yeast adapt over time to fit a certain brew?

So I am siting at home brainstorming and I was thinking: I know that certain organisms adapt themselves to the environment they are in over a period of time. So then I thought: Does yeast adapt to the same brew if it is used again and again with the same recipe? If i brewed a porter 5 times in a row and pitched on top of the same yeast cake would that yeast adapt to my brew and be a "special' strain for that recipe? If so, this could be a great project to try out

I'd venture to say yes.

Correct me if I'm wrong, but it's my understanding that this is how many strains of yeast came to be in the first place.

Anbrew said:

I'd venture to say yes.

Correct me if I'm wrong, but it's my understanding that this is how many strains of yeast came to be in the first place.

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thats exactly what i was thinking. I am going to do a test on this probably and keep a log book and post it on here when i am finished

This is a very interesting idea. I will look into this, as much as I can. Not only could the yeasties evolve, they also might change expression of different genes.

****Questions for the next geneticist I bump into****
1. Where would the yeast get the genetic variablity?

2. What is the mode of selection?

3. What would the end result be?
********

Let us know if the taste of your beer changes!
OR if the gravity readings slowly change!

I think it would be awesome to evolve your own yeast!

Doesn't Papazian have a "house" yeast that he's developed over the last 20 or so years?
Get to it.

Not only could the yeasties evolve

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I don't think that's really the proper term given the temporal limitations of this experiment.

1. Where would the yeast get the genetic variablity?

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From their genome. They have a good 32 chromosomes (when diploid). Though that's not always the best indicator...ferns have like 24,000 genes or something and have been relatively unchanged for millions of years.

2. What is the mode of selection?

-Natural Selection?

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Are you willing to continue to do this over and over for decades with the same exact recipe? Then not natural selection. If you had 4 concurrent batches, and 1 tasted best, you'd only culture the yeast from that batch and not the other 3 to make the next batches with, so it would be artificial selection.

3. What would the end result be?

-Would yeast 'evolve' to make more/less alcohol?

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Probably not, unless they magically evolved some way to break down different (additional) compounds than they already do.

-How many generations would it take to notice a difference?

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A whole hell of a lot, most likely. Not that that's a bad thing though, since the yeast generation time is pretty short. However, if the generation time is 1 hour, and it takes 50,000 generations to elicit 1 random base pair mutation....you see where I'm going. You'd have to hope there was enough variability in between batches for you to discern a difference, and keep REALLY good notes so you know how previous batches were. A change of 1 bp will most likely do absolutely nothing, and that's where the artificial selection comes in. If you let the yeast go on its own, mutation alone is not a sufficient force to drive selection. If the frequency of an allele that is favorable in your eyes is present only at 0.00000001%, the chances of it becoming fixed are 0.00000001%.

BigKahuna said:

Doesn't Papazian have a "house" yeast that he's developed over the last 20 or so years?

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Its White Labs 862 Cry Havoc. I think it was originally the Budweiser strain that mutated over the years.

Well it looks like I am going to get into this. Probably just pitch a neutral dry yeast like US-05. Now I just have to decide which type of yeast it will be? I will write up a outline for it later....i got to study right now

I asked a Microbiological Engineer (PhD) he said it would take a while but they would eventually adapt to optimize themselves for the environment.

The discussion started when I had to older cultures and decided to mix them as an experiment. The combination gave a unique flavor and we talked about if they were re-cultered together over a number of generations would they develop into a new strain with properties of both.. The conclusion was eventually yes, the yeast would be capable of adapting to working together and eventually become the same strain different from both the original cultures.

The conclusion was eventually yes, the yeast would be capable of adapting to working together and eventually become the same strain different from both the original cultures.

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Assuming that they both have the same temperature preferences, utilize all nutrients exactly at the same rate and with equivalent efficiency, both multiply at the same rate, etc. However in reality, the chances of one not having some sort of slight advantage over the other are slim to (almost certainly) none.

Yeast like all micro organisms will "evolve" relatively quickly. Whether this means better beer is questionable at best.

Sam adams will only repitch their yeast 16 times because of mutation.

How does white labs keep their yeast from mutating in their master yeast? Do they selectively test each single cell using DNA?

WBC said:

How does white labs keep their yeast from mutating in their master yeast? Do they selectively test each single cell using DNA?

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They take it from frozen glycerol stocks in their universal bank.

This is why I advocate decanting a portion of yeast slurry from your starter for storage rather than washing yeast post-fermentation. This way you are keeping the original yeast, not yeast that is stressed and possibly mutated from the fermentation process.

Another experiment that you can do to see firsthand the selective power the brewer has over their yeast is top cropping. I've done this with S-05.

Pitch for a normal beer for a normal fermentation. Around Day 2, when you have high krausen, I go in with my thief and get a couple pulls off the top. Let it settle, grow another starter for another beer (or pitch right away, although I wasn't brewing 2 days after my last batch). Do it again with the next beer.

What you are doing is selecting the most viable, active yeast. You should observe the second fermentation take off quicker, and go faster. Even more so with the third. The point is that once you pitch, all the most flocculent, less viable yeast is going to fall to the bottom.