Weyermann's acid malt is an acidulated malt that contains a small percentage of lactic acid (usually around 1 to 2% by weight) on the husks. It is used to adjust mash pH in beer. Weyermann states on their web site that reducing mash pH can lead to a better mash, intensified fermentation, lighter color for Pilsners, improved flavor stability and a well-rounded beer flavor. Acid malt is usually used in small proportions to adjust pH. It has been noted that for every 1% of the grist comprised of acid malt, a 0.1 drop in pH can be expected. Usually used as 1 to 5% of the grist for pH adjustment, it can also be used at a rate of 8 to 10% of the grist for sour beers such as Berliner Weiss to bring out sour character. Many people also use a small percentage (around 3%) in classic dry Irish stouts to give a characteristic sour note on the finish.