For my next batch I will be sneaking 27 gallons into my 31 gal conical, which will put the top of the wort about 3 inches from the top. I wanted to use Fermcap but my LHS only had Anti-Form. I am assuming that both products are the same, so I’m planning on 1/2 tsp of the Anti-Foam (also into the boiler). Just looking for a little confirmation since I’ve never used either product.
I haven’t used fermcap, but I’ve used the anti-foam granules. I buy it in 5g sachets, and find that i need the whole thing for a 10 gallon batch to avoid boil-over in my kettle. I’ve added another 5g in the fermentor with a vigorous fermentation, and it still blew off pretty hard.
I ended up using 1 tsp in the boiler, which did a good job of stopping a boilover when the wort was 3 inches from the top and roiling.