If hops supply a beer’s characteristic bitterness, malt is where a beer derives its sweetness. But what is malt, exactly?
Malt is the last stage of processing for a grain, usually barley, which has been germinated and then dried while the native enzymes and sugars are at their peak. Home brewers typically buy malt in one of three forms. As a whole grain, malt is typically crushed or lightly ground to open up more surface area during the mashing phase of all grain brewing. (For more on the malting process, see ‘How Do You Get Sugar From Grain?‘)
As extract, home brewers may buy cans or jars of liquid malt extract (LME) or bags of powdered dry malt extract (DME). Brewing with extracts doesn’t carry the same gravitas that all grain brewing confers, but plenty of award winning homebrews were sweetened with LME or DME.
Many grains can be malted, including wheat, rye, and even corn. Malted barley holds a special place in the brewer’s mash tun for a few reasons. Because of its high enzymatic activity, barley does an excellent job of converting not only its own starches into sugar, but helps liberate the sugars in specialty malts which may have no enzymatic activity. Barley is also lower in protein than wheat, which contributes a certain amount of cloudiness to various styles of wheat beer.
When you hear the term “diastatic,” it is in reference to the enzymatic activity of base malts like barley and wheat. Specialty malts and grains are often non-diastatic, meaning that they lack the enzymes to convert their starches into sugar. By limiting specialty malts and grains to a low percentage of the total grain bill, non-diastatic malts can be used to contribute various flavor, color, and texture elements to the beer, while the enzymes in the barley or wheat base malts convert the available sugars in the non-diastatic ingredients.