Harvesting yeast from the bottom of a keg?

[zanemoseley]

I'm curious, seems like most people use the junk from the bottom of the primary for washing yeast. I usually don't filter out cold break or pellet yeast from my wort so this would be pretty nasty stuff mixed with the yeast in my fermeters. I was thinking why not harvest from the bottom of a keg? I usually have a thin layer of yeast with a small amount of hops and other matter in the bottom of my kegs when I wash them out. It seems as if this would be prime yeast to possibly wash once and reuse. Does carbonating have any affect on yeast?

 

[mb2696]

One thing you may want to keep in mind is that the yeast that makes it to the bottom of the keg is the last yeast to settle out. That yeast may have qualities that you might not want to pitch (slower and/or less flocculent and/or lazier)?

I think the middle layer of the primary yeast cake is generally considered the best to save. I've never taken yeast from the secondary or keg though, so who knows, maybe it's fine? I don't think the carbonation itself causes any problems -- cause think about it, people culture yeast from commercial bottles all the time.

 

[zanemoseley]

Lazy yeast lol, listen mofo's you punk a$$ b!tches need to get a job. I guess I get what you're saying but to me it seems more like chance that they settle last, kind of like blowing out a woodworking shop, the majority of dust will settle quickly but a good bit is still settling after hours. I don't like to attribute more advanced qualities such a "lazy" and "slow" to a minuscule yet astounding organism. I'm pretty intrigued by slanting so this may be my first attempt at reducing the cost of liquid yeast while giving me something fun to do between brewing.

 

[mordantly]

+20 on slanting your boys.

 

[mb2696]

Lazy yeast lol, listen mofo's you punk a$$ b!tches need to get a job. I guess I get what you're saying but to me it seems more like chance that they settle last, kind of like blowing out a woodworking shop, the majority of dust will settle quickly but a good bit is still settling after hours. I don't like to attribute more advanced qualities such a "lazy" and "slow" to a minuscule yet astounding organism. I'm pretty intrigued by slanting so this may be my first attempt at reducing the cost of liquid yeast while giving me something fun to do between brewing.

actually it looks like the opposite of what i said is true...

http://www.howtobrew.com/section1/chapter8-1-1.html

palmer says you should take it from "the primary yeast cake and preferably from the upper layer of the cake or from the secondary. This yeast will have the optimum characteristics for re-pitching." so that means the first yeast to settle out are the LAZIEST


seriously though, saving slurry is so easy and works great as long as you brew more than once a year. i don't filter out my cold break, i don't wash my slurry either. never any off flavors or problems. no need to make a starter. slanting just seems like so much work.

 

[dobeluvr]

don't know if I'd call it lazy or not, but in nature there is this thing called survival of the fittest, makes sense that the ones still working are the fittest

 

[Synovia]

One thing you may want to keep in mind is that the yeast that makes it to the bottom of the keg is the last yeast to settle out. That yeast may have qualities that you might not want to pitch (slower and/or less flocculent and/or lazier).

Slower and less flocculant?


Or is it stronger, and more vigorous? The other yeast is pooped at this point, this stuff is still out there eating sugar.



I'm not convinced it matters either way.

 

[tidehouse]

I thought the point of washing the yeast is that it separates the yeast from the rest of the junk since the yeast takes longer to settle out. You can just pour the yeast off and leave the junk behind.

 

[zanemoseley]

I've never washed yeast but was looking through the illustrations and I though when you initially added the sterilized water and let the trub settle back down you didn't want the stuff on the bottom (trub). Then once you have the washed yeast in the smaller containers the yeast would settle to the bottom. So esentially whats on the bottom of the keg would be very similar to what would usually be washed out normally.

 

[zanemoseley]

Update: I finished drinking my keg of Hefeweizen that used the WLP300 Hefeweizen yeast, there was a nice layer of yeast with very little trub/hops at the bottom of the keg. I boiled and cooled about a cup of water and dumped it into the keg, swirled and poured into a flask of boiled/cooled wort (2 cups water, 1/2 cup X-light DME). After fermenting on the stir plate I decanted and added another 2 cups of DME wort. I decanted a bit off the top of this so everything would fit into a pint mason jar. After a couple days I have a nice healthy looking 1/2" or so of healthy looking yeast at the bottom. After I get my hops from hopsdirect.com I will try it out but I'm almost sure it will be successful. Now I need to do some reading about how many times you can do this with a yeast before it gets mutated or contaminated.

 

[TristanL]

You'll have to keep us updated on how your Hefeweizen using the yeast from the bottom of the keg turned out!

 

[zanemoseley]

Well I made 10g of Hefe from the harvested yeast and everything went fine. The more I thought about it the more its really just like harvesting yeast from the bottom of a large bottle. I also have 10g Hobgoblin II fermenting away in the basement with WLP002 I harvested from a special bitter.

 

[kanzimonson]

I think the point people were trying to make earlier is this: if you keep harvesting from your keg, you're selecting the yeast that are the very last ones to flocculate and drop out. Keep doing that, and you may end up self-selecting a yeast strain that NEVER drops out.

I also suspect that because these self-selected yeasts are essentially heartier and able to continue fermenting for longer, your WLP002 (typically a lower-attenuating strain) will have higher attenuation than normal. Was the FG on your Hefe lower than expected? Does it have more yeast haze than expected?

And when you say "it's really just like harvesting yeast from the bottom of a large bottle," are you referring to homebrew or commercial beer? You're correct if you mean homebrew, but as for commercial breweries, they filter their beers and then repitch for bottle conditioning, so you're essentially getting the full spectrum of the yeast when it settles to the bottom.

 

[zanemoseley]

Perhaps I don't give the yeast enough credit but I don't think there's as much diversity in characters from cell to cell of the same strain when we pitch. I don't think the last yeast to settle is substantially different than the first or middle drop outs. I didn't measure my FG of the Hefe as I rarely do anymore. If I pitch an adequate amount of yeast and give adequate time to ferment before racking to the keg (I always allow at least 2 weeks) I don't see a reason to worry about FG unless you're really concerned about the ABV.

 

[kanzimonson]

How can the yeast be exactly the same and yet drop out at different times? Mutation is not hard to imagine when you have a sample that contains thousands of generations.

Imagine this: you are able to perfectly isolate some of the cells that drop out at the very beginning of fermentation and some of the cells from the bottom of your keg. Then you brew a beer, split it into two fermenters, and compare these two "strains" of yeast. Don't you think one would finish fermentation quicker than the other, but it would probably still have a lot of leftover fermentables in solution?

I think you're thinking of the entire colony of yeast as one organism that reacts to its environment in a certain way, but never forget that there are thousands more cells in that one beer than all the humans living on Earth now, and it looks like we've developed quite a bit of individual variation.

As for checking FG, sure you can probably estimate what it's going to be based on your yeast's standard attenuation percentage but there are so many other factors and I want every data point I can get, especially if it comes to trouble shooting.

 

[zanemoseley]

I guess I live by the K.I.S.S. principle. I got my brewing process fairly down pat. I get consistent efficiencies from 75-80%, I sanitize to the best of my ability, I make good sized starters and allow my beer to fully ferment. I don't worry anymore about attenuation or FG as I've never had an under attenuating batch.

I can appreciate complex organisms like yeast but at the same time try to "keep it real" with my approach to my process. If the worst I have to worry about by taking the "bottom of the keg" cells is having a yeast that is too hard working then I can deal with that. If I notice some really dry beer then perhaps I'll re-evaluate my process but for now its a way to easily re-use yeast and save $6 a batch. Got my 10g batches down to about $25 by buying hops in bulk, using "washed" yeast or dry yeast and using my house's NG instead of propane.