Yeast farming?

[CoopsOz]

I know that you guys take some of spent yeast from the bottom of your wash, give it some food/nutrients and throw it in the fridge for next time. Why is it done that way? Is there a reason why you can't take half your starter and put it in the fridge for next time? That way the strain is less likely to be stressed...or am I barking up the wrong tree?

[msrorysdad]

I am experimenting with this myself. I plan on unfridgeing some this weekend to start a new wash, I'll let you know how my test works. I am mr. cheap yeast, but I still was curious as to how that would work. I'll let ya know by Sat. how it went for me.

[junkyard dawg]

One reason for getting it from your wash is that there will be many more yeast cells in the fermenter than in the starter. Another is that the yeast strain in the fermenter will have grown and adapted to the particular wash. That can be good or bad... If you have had a good fermentation and no infections or other bad flavors, etc... then use the yeast from the fermenter...

good info here:

http://www.lalvinyeast.com/library.asp#

[Uncle Jesse]

I have done this many times. It helps to have a conical fermenter. Mine has a nice valve on the bottom which I can open very slowly. I collect the white yeast from the bottom of the fermenter for re-use.

I've done this for many generations with beer and it worked quite well. Be careful about what you collect, you want to keep it relatively clean which is why I only take out the white part of the lees.

[Samogon]

Is there a reason why you can't take half your starter and put it in the fridge for next time?

That is what I do to maintain a pure strain - keep about 1/8 of the starter. You do have to keep feeding it occasionally. I'd rather keep a stock of pure stuff for making more starters than risk contamination. But the above posters have valid points about ease, quantity and adaptation.

However, adaptation isn't always what you want. I use the same yeast for everything and I wouldn't want to harvest yeast from something like a UJSM (super low pH and gotta be full of lactic bacteria from the uncooked corn) and start a brandy or something with it. Yeast can be washed and recultured, info on how to do it is in many beer brewing books and I'm sure online somewhere.