Acidulated Malts2 products
Because of German purity laws (the Reinheitsgebot) that prevent additives to German beer, sour malt (called acid malt) is used to aid in the brewing of light beers to lower mash pH. Acid malt is made by souring malt with lactic bacteria for a short period which effectively creates lactic acid. Adding acid malt is effectively equivalent to adding lactic acid to the mash.
Acidulated malt is designed to be used to adjust pH in the brew house mash. Acidulated malt encourages lactic growth during germination from naturally present bacteria on the grain, and then washing the malt in a lactic bath using the same Lactobacillus strain, before kilning.
As a guide, 1% of this milled malt will drop mash pH by 0.1. It can also add a mild lactic sourness to the brewed beer.
1% to 5% of Acidulated malt is used to achieve target mash pH.