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Question about Fermcap-S

I just ordered a bottle of this to help with boil overs and blow off. I read somewhere that if you use it, you should either use it either in the boil or in the fermenter, but not both.

If that is the case, in which instance does Fermcap-S work better?

I am more inclined to use it in my fermenter due to the fact I have had more issues with blow off than boil overs.

I just wanted to get peoples opinions on the subject.



I use it in the fermentor when I notice that I am getting some yeast/krausen in the airlock. Recommended drops and it does seem to work well. I was concerned that it would slow or stop fermentation but that does not seem to be the case.

I’ve always just added it to the boil.
I pour from the BK to the fermenter so it carries over that way.
Use it in my starters too, so I carry some over from that too, I suppose.
I don’t see why you couldn’t add it to the kettle and the fermenter if you wanted to.

I use it in starters, in the kettle and in the fermenter…wherever, whenever you need it. Who said you should only use it one place or the other?

I regularly use 1 drop in starters, 5-6 drops in the boil and then 5-6 drops in the fermenter (5 gal.) and have never had problems (or boilovers!).

I read it after I googled “Fermcap-S.” On the second page.

I’ve used it in my last 4 batches. I added 2 drops per gallon with 15 minutes left in the boil. I don’t know if that’s really the right time, but that’s when the guy at my LHBS told me to do it. At any rate, it has definitely achieved its intended purpose of stopping blowoffs in the fermenter.

Another question.

When it says use 2 drops per gallon, I assume that means at current volume and not final volume.

Is this correct?

Um, there are about a dozen links on the 2nd page…


the link I was referring to: ... 1304008514


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