Weyermann Acid Malt 1 LB
A malt high in the phytase enzyme, which breaks down phytin into phytic acid, thus lowering the mash pH. Typically only used in Germany, where the Reinheitsgebot prevents brewers from using food-grade acids to do the same thing. Acid malt available in a one pound bag or by the oz.
All homebrew grains are sold by the pound. You also have the ability to add tenths of pound amounts.