I did actually hunt down the specialist at the manufacturer of Whirlfloc. The company that makes Whirlfloc tablets is Quest International in Ireland and the contact was Liam Holog? Anyway I learned several interesting things from this very friendly, knowledgeable and interesting man (he even wanted to idle talk for quite some time):
1. Whirlfoc is refined kappa carrageenan with some talcs to help in tabulation.
2. pre-hydrating whirlfloc does nothing at all to increase effectiveness. In fact it's not even water soluable at lower temperatures so all you'd be doing is getting it wet.
3. most interesting: do NOT add whirlfloc any earlier than 10 minutes before end of boil. It acts immediately and at most only really needs 5 minutes in the boil. If you add it earlier you will denature the carrageenan (not quite sure what that means - anyone?).
4. The manufacturer recently has done some google searching and was surprised that it has become so popular amongst homebrewers. Their target is large breweries and they only sell it through large distribution chains so wasn't aware it was going out to LHBS suppliers in the current volume.
5. if you are adding any more than one tablet for 5 gallon batch, don't bother. One tablet is 2.5 times the dosage they recommend. For record: one tablet is 2.5 grams. They recommend 5 grams per hectoliter (2 tablets to about 25 gallons).
