First, a bit on what enzymes are. They are large biological molecules that are a catalyst for chemical reaction. They are specific to their substrate (the start product, like starch in the mash) for a specific job (like converting that starch to sugar). They are responsible for chemical reactions that make life, and beer, possible. Though enzymes are not living, they have some biological properties and once they are made inactive, they don’t come back (known as denatured rather than dead).

In the mash there are many different enzymes that we may or may not want to take advantage of. Enzymes in the mash are not only responsible for starch conversion, but also to help lower pH, break down gum and proteins, and help produce Free Amino Nitrogen (FAN, a yeast nutrient). Also, there are several enzymes to convert the starches to different types of sugars, some more fermentable than others.

The major enzymes that are important for the mash are:

Phytase
Temp range: 86-126°F
pH: 5.0-5.5
Used to lower the pH of the mash

Beta Glucanase
Temp range: 95-113°F
pH: 4.5-5.5
Breaks up gum

Debranching
Temp range: 95-113°F
pH: 5.0-5.8
Used to help make starch more soluble

Protease
Temp Range: 113-131°F
pH: 4.6-5.3
Helps breakdown haze forming proteins

Peptidase
Temp range: 113-131°F
pH: 4.6-5.3
Produces Free Amino Nitrogen (FAN).

Beta Amylase
Temp range: 131-150°F
pH: 5.0-5.5
Converts starches into maltose (sugar)

Alpha Amylase
Temp range: 154-162°F
pH: 5.3-5.7
Converts starch into sugars, not just maltose, but also longer chain sugars

The two most important enzymes are Beta and Alpha Amylase as they convert the starches to fermentable and body building sugars. Rests in these temperature ranges are called sacch’ rest because the starches are being prepared for the Saccharomyces (brewers) yeast (Beta Sacch’rest and Alpha Sacch’rest).

Enzymes in the mash are dependent on a few things to work. Mash temperature and pH, mainly, and to a lesser extent, mash thickness (the grain to water ratio). Most brewing related enzymes work within a similar pH range so we typically aim for the middle and it works pretty good—5.2 to 5.6 is the happy range. Temperature, on the other hand, is the brewer can manipulate the enzymes to do their bidding. Specific temperature rests can vary the outcome.

When mashing in (mixing the water and grain) there are a few things to keep in mind. The temperature of the mash is very important as it turns on or denatures the enzymes, the pH of the mash will help or hinder the enzymes, and the consistency of the mash will help to ensure proper conversion.