How do you guys harvest yeast? I have only done a "yeast wash" using the primary fermentor trub collection method. I keep reading about "top cropping" but have no knowledge of the method. Doesn't top cropping remove yeast that is in the process of fermenting your beer?
in essence, but those yeast are not working on sugars in solution at that time...they have bubbled out, but that is not to say they won't play a potential role in the finishing steps. I won't top crop in high gravity beers to make sure they finish strong. But for beers up to maybe 1065 og, I'll scoop out maybe 50%-75% of the krausen leaving enough "just in case". I have not had problems with high terminal gravities in beers I've top cropped staying within my own made up guidelines.
I've had nothing but good luck with yeast washing. I usually just use a sanitized spoon and remove all of the ring from where the high krausen was. I add this to the trub of the fermenter and it all goes into a 1 gal fermenter. I add some sanitized water to this to fill a 1 gal fermenter and it sits until I make my next yeast starter. I just pour out the water, add wort and eventually pitch the whole thing into my next batch. I usually only get a strain to go through about 2 or 3 beers. I'm just lazy about reusing them. After they're over 4 or 5 months old I throw them out.
I wash yeast from trub. I tried harvestng from krausen a few weeks ago and was disappointed with the harvest. By the time the foam subsided, I had a few cc's of slurry. I didn't bother to use it to make a starter. I harvest by scooping almost a 1/2 pt of trub into a pint jar, fill with water to just short of the top, shake, stick in the fridge. When I want to use it, I pour off the top liquid and use the layer just below it for the starter. I used to be careful about using the dead cells/hop gunk but not anymore. I don't pour it in on purpose, but I figure that it is better to err on the side of more yeast than less so I don't worry about getting the trubbiest part of the trub in my starter.
