Every pkg of "Grape Tannin" I've found, from every supplier I've checked with, is actually either mimosa or chestnut.They're not all the same. I have some mimosa tannin but I have to admit that I've never used it.
Thanks for the link, Wade. Looks like Biotan is the only one that's grape-derived out of their many tannin products.Scott laboratories has some that are ether extracted from grape skins and seeds or from French oak or American oak or even the Chestnut. In my opinion they have the best tannins out there and many other products also. Id look into some of their tannins for someone serious about making wine.