Gladfield’s Sour Grapes Malt is designed to be used to adjust pH in the brew house mash. Sour Grapes Malt is produced by encouraging 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. We recommended between 1% and 5% of our Sour Grapes Malt is used to achieve target mash pH.