I've got a load of this stuff from when I was 'brewing' CO2 for my planted aquarium before I moving house. I don't expect much from it as a yeast to pitch (although it may be okay but I have no idea what strain it may be), but I was thinking about chucking a load of it in the boil to provide some nutrients to the usual S-04 I use.
When should such things be added to the boil and in what quantities? I guess a little's better than none...
Holland & Barrett Brewers Yeast powder