Mashing - Decoction Mashing

Decoction Mashing

Decoction mashing is where a proportion of the grains are boiled and then returned to the mash, raising the temperature. The boiling extracts more starch from the grain by breaking down the cell walls of the grain. It can be classified into one-, two-, and three-step decoctions, depending on how many times part of the mash is drawn off to be boiled. It is a traditional method, and is common in German and Central European breweries. It was used out of necessity before the invention of thermometers allowed simpler step mashing. But the practice continues for many traditional beers because of the unique malty flavor it lends to the beer; boiling part of the grain results in Maillard reactions, which create melanoidins that lead to rich, malty flavours.