The Heart of Brewing
Mashing is where brewing begins in earnest. Crushed malted barley is mixed with hot water, activating endogenous amylase enzymes that systematically disassemble starch granules into fermentable sugars. The brewer's primary lever is temperature: a few degrees up or down shifts the balance between fermentable maltose and unfermentable dextrins, fundamentally changing the finished beer's body, sweetness, and alcohol content.
Two Enzymes, Two Personalities
Beta-amylase is the precision cutter — it nibbles maltose disaccharides from the non-reducing ends of starch chains, producing highly fermentable wort. But it denatures above 70C. Alpha-amylase is the demolition crew — it cleaves random interior bonds, creating a spectrum of sugars and dextrins, and survives up to 76C. The interplay of their temperature and pH optima gives brewers fine control over wort composition.
Kinetics and Denaturation
Enzyme activity follows Michaelis-Menten kinetics, but with a twist: the enzymes themselves denature over time at mash temperatures. Beta-amylase loses half its activity in about 40 minutes at 65C and in just 10 minutes at 70C. This time-dependent denaturation means that a 60-minute mash at 66C produces a very different wort from a 20-minute mash at the same temperature. The simulation models both reaction rate and thermal denaturation.
Practical Mash Design
Single-infusion mashing at 65-68C is the workhorse of modern brewing. Step mashing (resting at 62C then 72C) can fine-tune fermentability for specific styles. Decoction mashing boils a portion of the mash to gelatinise stubborn starches and develop melanoidin flavours. This simulator helps you predict conversion completeness, fermentability, and optimal mash duration for any target profile.