Originally Posted by bzwyatt
Yeast can improve performance in successive generations.
Understood but this isn't really the point. We're talking about the mechanics of yeast harvesting. It's about what purpose the yeast harvesting is serving. I see three cases (there may surely be more, like a plating and a real yeast bank, but these are easy, common, homebrewer methods):
1. brewing a small beer so that you can build up a nice yeast cake for a big beer,
2. washing the post fermentation yeast for repitching in future batches.
3. collecting small portions of yeast harvest from new starters for freezing.
#2 is beneficial to those who brew often and large jars of yeast kept in the fridge won't just go bad from non-use. The downside to #2 is that the longevity of the yeast is directly dependent on the quality of the wash job. And it's a fair bit more work than #3.
#3 is great for people like me who like to keep a couple yeast strains around for months, for the occasional brew session and to save a few bucks. for example, I have a saison strain that I'll use 2-3 times a year, and when the slants are gone I buy a new tube. It's very easy to pull a small portion of yeast, with minimal cleaning effort, from a fresh starter for freezing, then just dump the rest of the starter yeast into the fermenter for the current brew session. I really only need to buy one tube of the few strains I use each year, brewing once or occasionally twice a month.
No disrespect to JZ (cuz I've certainly learned a lot from him and I will be buying the book), but to those of us who listen to the BN, don't you ever get the impression that their ideas are *very* west coast centric. They drone on and on about dry beer and attenuation being king. JZ probably sneezes chico strain. JZ flatly even said he didn't have any really good east coast beer from his recent trip (NHC). East coast beer is generally sweeter than west coast beer. The yalso have a half hearted grudge against midwest and east coast breweries evident whenever top beer lists are brought up, etc. Somehow sweet beer is under attenuation or poor recipe development. A good example of the differentiation is the last Session podcast, with Summit Brewing out of Minnesota. The brewer guest (Damian McConn, classically trained in the UK) had a very nice discussion regarding the benefits of different types of malts, how US malts are highly enzymatic, the benefits of less attenuating and estery yeast, and the delicateness and difficulty of obtaining a quality residual maltiness/sweetness in a beer, especially in the smaller beers common in other parts of the world. There's more than one way to skin a cat and all are correct in their own way and for their own reasons...just like what we're talking about here with yeast washing.