Whether you prefer simplicity or dig technical minutiae, understanding the many means of mashing will help you choose the right mash for the job.
Single-Step Infusion Mash
Most all-grain homebrewers use a single-step infusion mash. Hot water is mixed with crushed malt to achieve a specific temperature, usually between 148°F and 158°F (64°C and 70°C). The mash is held at this temperature for an hour or so (longer for lower temperatures) and immediately sparged.
The appeal of this mash protocol lies in its simplicity and in the fact that it can be executed with very simple equipment. Homebrewers who mash in an insulated cooler use this regimen more than any other. Well-modified malt is required for a single-step infusion mash, but unless you specifically seek out under-modified malt, you’re unlikely to come across it in your homebrewing adventures.
Multi-Step Temperature Mash
In a multi-step temperature mash, the mash is carried through a series of rests, or temperatures, that are held for a certain period of time. A typical mash regimen might include the following:
- A protein rest at 113°F to 130°F (45°C to 54°C)
- A beta amylase rest at 140°F to 150°F (60°C to 65°C)
- An alpha amylase rest at 160°F to 165°F (71°C to 74°C)
- Mash-out at 170°F (77°C)
Such a mash protocol is most appropriate when the malt isn’t fully modified or for brewers interested in German brewing practices. Homebrewers who want to execute a stepped temperature mash typically use a direct-fired mash tun or similar vessel in order to raise the mash temperature through the various steps.
With some planning, homebrewers who mash in an insulated cooler can pull off a multi-step mash by adding infusions of boiling water to achieve the steps.
Decoction mashing originated in Continental Europe as a way to maximize the extract efficiency of undermodified malts in the days before reliable thermometers. A decoction is a portion of the mash that is removed, boiled for a period of time, and returned to the main mash. By pulling decoctions of known volumes, the brewer can achieve a stepped mash without a direct-fired mash tun because the boiling point of water is known.
Homebrewers rarely perform decoction mashes because there’s rarely a need to do so. But those who are looking for a challenge or who want to spend more time with their grain might consider a decoction mash for the simple thrill of it. Certain flavor compounds can only be achieved through decoction, but judicious use of melanoidin malt can approximate these flavors with considerably less effort.