I'm brewing a stout tomorrow, and I want to Dublinize my water, which means adding a lot of calcium but not sulfate (which gypsum also adds).
I though I had some calcium carbonate, but I guess I don't. Any idea where one might find that, other than at a HBS. (The nearest HBS is an hour away.)
It's not a big deal: if I can't find any, I'll just do without.