In our most recent experimental single hopped Saison, Motueka, we threw in some acidulated malt, just for fun!
Also known as Sauermalz, Acid Malt, or Sour Malt, Acidulated malt is a type of malted barley that contains a small amount of lactic acid that gives it a sour taste. Acidulated malt is most commonly used in small amounts (1-5%) to reduce the pH of the wort or mash. It can add complexity and slight tartness that helps highlight certain hop flavors.
In Motueka, we added 3% acidulated malt to highlight some of the Motueka hop flavors, such as lemon, lime, and passion fruit, and to give it an interesting mild tartness.
At greater amounts (8%), it can be used in certain beer styles to help sour, such as Berliner Weisse and Gose beers, instead of souring the kettle by putting lactobacillus strains straight in the kettle.
Weyermann® acidulated malt is soured with naturally occurring lactic acid that they propagate from wort, following the German Purity Law, which states beer can only be produced using water, barley, and hops. Although exact details of the acidulation process remain undisclosed, the process is similar to the production of other malts. They use a pale barely malt that is steeped, germinated, kilned, and acidulated.
Always learning something new!