What temperature is best for a dry, attenuated beer?

Rest low, around 62 to 64 Celsius, where beta-amylase dominates. Beta-amylase cuts fermentable maltose from the ends of starch chains, so the yeast can ferment more of the wort and finish drier.

What temperature gives a fuller-bodied beer?

Rest high, around 68 to 70 Celsius, where alpha-amylase dominates. Alpha-amylase cuts chains internally and leaves more unfermentable dextrins, which keep body and a touch of sweetness in the finished beer.

Do I still need a protein rest with modern malt?

Usually not. The protease and peptidase rest around 45 to 55 Celsius matters mainly for under-modified malt or high adjunct mashes. With well-modified modern base malt a single infusion rest is normally enough.

What is a beta-glucan rest for?

Around 35 to 45 Celsius, beta-glucanase breaks down gummy beta-glucans found in wheat, rye, and oats. It improves lautering and run-off speed for mashes heavy in those grains.

Why do enzymes stop working above 72 Celsius?

Enzymes are proteins and denature with heat. Above roughly 72 Celsius alpha-amylase quickly loses activity, which is why a mash-out at 76 to 78 Celsius is used to lock in the sugar profile and thin the mash for lautering.

Mash Enzyme Activity Temperature Guide

The temperature you hold your mash at decides how fermentable the wort is, and therefore how dry or full the finished beer tastes. This guide lays out the active temperature window for each of the main mash enzymes and tells you which ones are working at any rest temperature you enter.

How it works

Each starch-degrading enzyme has a band where it is most active. The two that matter most for the sugar profile are the amylases:

Beta-amylase (54–66 Celsius): snips fermentable maltose from chain ends, so a lower rest yields a more fermentable, drier, more attenuated wort.
Alpha-amylase (66–72 Celsius): cuts chains internally and leaves longer dextrins, so a higher rest yields a fuller, sweeter, less fermentable wort.

Supporting enzymes — beta-glucanase, protease and peptidase, alpha-glucosidase, and phytase — work at lower temperatures and affect lautering, yeast nutrition, and pH. The tool marks each as active or inactive at your chosen temperature and estimates how close you are to its peak.

Tips and example

A single-infusion rest at 65 Celsius sits in the overlap of both amylases and produces a balanced, medium-bodied beer — a safe all-rounder. Drop to 63 Celsius for a crisp, dry pale ale, or climb to 69 Celsius for a fuller stout or sweeter malt-forward style. Step mashes string several of these rests together: a short beta-glucan and protein rest before the main saccharification rest, finished with a mash-out near 77 Celsius to denature the enzymes and fix the sugar profile.