Fermcap and yeast harvesting

[pfooti]

There's a lot of discussions about fermcap, pretty much all the time. I've recently started using it, and I really like it. Seems to prevent boilover, blowoff, and most importantly it allows me to aerate my wort without foam going everywhere. I'm trying to use it as sparingly as possible, but I am worried about "concentrating" it by repitching yeast.

As I understand it, the fermcap stuff drops out of the beer by adsorbing to hop material, break proteins and importantly, flocculating yeast. Has anyone had any experience with harvesting and rinsing yeast for several generation in a fermcap-positive environment? It is conceivable that by the sixth generation you've got a pretty considerable amount of fermcap there, all concentrated in the yeast slurry you're trying to harvest and protect.

I'll be keeping an eye on this myself over the next couple of months, but so far it is the only thing that I'm worried about with this fermcap stuff. It's really made my brewing a lot easier. Thanks northern brewer!

[spiderwrangler]

Are you rinsing your yeast (the way JZ describes)? I'd speculate that the stuff will drop with the other trubby bits and dead yeast, so there isn't likely a lot going over in the pitched portion.

[pfooti]

Yeah, I'm rinsing it. The only real question is- does the stuff adsorb to the living yeast cells? Some people indicate that it adsorbs to the yeast when they floc out, which wouldn't be too big a deal in the first few repitches, but once the yeast get to the 6th or later generation it might add up. Only one way to find out: brew a lotta beer.

[spiderwrangler]

Well, should be able to find that out by just doing two batches... Fermcap the first one, collect and rinse your yeast, pitch them into a second that has no additional fermcap added. If you get no noticeable krausen, then it's likely still there, if you get crazy krausen, it's probably not an issue in terms of the buildup you are concerned about. My speculation is that it isn't going to get carried over with the yeast if you are rinsing and pitching the supernatant.

[Travisty]

As far as I know Fermcap doesn't adhere to particles at all. It's not a fining agent. It just breaks up the surface tension of the wort so that foam cannot form. It does drop out with the yeast, but I would be willing to bet that any Fermcap that does get carried over with a repitch will not effect the performance of the yeast. I would think of it more as an additional trub component.