Some were asking about storage
Per wyeast -
Stability: 1 year, stored in airtight container in cool environment
Yep, can't hurt. And after all of my protestations, I tokk the extraordinary measure of actually contacting Joe to get usage info..surprise, surprise, I was wrong...again....here's what he said...
I add 1/4 tsp per 5 gal of strike and sparge water, and 1/2 tsp as a slurry 15-16 min before the end of the boil. If you like using the Irish moss for 15, then add it 1 min before that.
So it is water volume based, not batch volume. And it does indeed go in the sparge, too.