Beer Fact Friday: Mashing
Welcome back to BFF, beer nerds. We continue this week with our step-by-step overview of the brewing process. Last time, we covered milling, the first step that occurs at the brewery. This week it’s on to step two: mashing.
Mashing is the term given to the part of the brewing process during which crushed grains are mixed with hot water to form a porridge-like mixture called the “mash.” Mashing occurs inside a brewhouse vessel called a “mash tun;” it’s here that starches trapped inside malted grain are transformed into sugars and proteins, mixing with the water and creating the sweet fermentable liquid we call “wort.” The compounds extracted from the malt during mashing not only provide the beer with flavor and color, but will also serve as food for the yeast later on in the brewing process.
The main purpose of the mashing process is to activate the malt’s enzymes—substances contained within each kernel that act as catalysts to bring about specific biochemical reactions. By controlling the temperature and pH of the mash, a brewer can control which enzymes are most active, and can thus influence the flavor, body, appearance, and alcohol content on the finished beer.
Protease, for instance, breaks down proteins in the malt and is most active between 95°–113°F; controlling for this enzyme can determine the quality of the foam head on a pint of finished beer. Alpha amylase, which prefers a mash temperature of 145°–158°F, breaks down starches into complex sugars that contribute to a beer’s body and sweetness but aren’t fermentable by yeast. Beta amylase breaks down those complex sugars into simpler ones like maltose and glucose—which yeast *can* ferment—but it prefers slightly cooler temperatures, around 131°–149°F. By favoring one enzyme over another, brewers can determine if the finished beer will be sweet and viscous, dry and watery, or somewhere in between.
The mashing process usually takes 30-90 minutes to complete, though certain strong beers sometimes require a longer mash. After that, the liquid wort is separated from the (now spent) grain in a process called lautering. But that’s a topic for next week.
Beer Fact Friday is our weekly exploration of the topics that make beer the world’s most interesting beverage. Check back here next week—or follow us on Facebook, Instagram, or Twitter—for more fascinating beer trivia.