All-grain homebrewers can make the vast majority of beer styles using a simple single-temperature infusion mash. Hot water and milled grain are combined to achieve a specified mash temperature, usually around 148–156°F (64–69°C), and then the mix is held for 60 to 90 minutes before lautering. Today’s highly modified malts make such straightforward mash techniques possible and place all-grain methods within the reach of most brewers.
The beauty of the single-temperature infusion mash is that it strikes a compromise between the activities of beta amylase and alpha amylase enzymes for the sake of simplicity. A handful of beer styles, however, such as Pilsner, Märzen, Bock, and other Continental lagers, can benefit from a more involved mash schedule. This is especially true when they’re built upon certain malts from Germany, Belgium, and the Czech Republic, which can be (though certainly not always are) less modified than those from North America and the United Kingdom.
Multi-rest mashes carry the grain bed through an increasing series of temperatures to favor different enzymes at different lengths of time. Historically, such mashes may have included acid rests, beta-glucan rests, protein rests, and other low-temperature steps. Today’s malts, however, rarely need to spend any time in these regimes, even less-modified malts. Thus, a modern multi-step mash may only spend some time in beta-amylase territory before jumping to the alpha-amylase rest and mash out.
The Hochkurz mash is arguably the most useful stepped-mash protocol available. Deriving from the German words hoch and kurz, meaning “high” and “short,” respectively, the Hochkurz mash is so-named because mashing begins well above the protein rest (hence, high) and requires less time than other traditional mash regimens (thus, short). A typical Hochkurz mash might proceed as follows:
- Beta amylase rest: 144°F (62°C) for 30 to 45 minutes
- Alpha amylase rest: 160°F (71°C) for 30 to 45 minutes
- Mash out: 170°F (77°C) for 10 to 15 minutes
You can move the mash from one temperature to the next using hot water additions, direct heat, or decoctions. If you use decoction or direct heat, then a normal water-to-grist ratio of about 1.25 quarts per pound (2.5 liters per kilogram) is suitable. Those relying on hot water additions, however, may wish to mash in a little thick since the subsequent infusions will dilute the mash. Fortuitously, the progressive thinning of the mash tends to favor saccharification and is thus well-suited to this kind of protocol.
Whether a more complex mash regimen is worth the extra effort is your call: The opportunity to select what works best for you is one of the great virtues of homebrewing. But the relative simplicity of the Hochkurz technique offers a chance to experiment with stepped mashes without committing to a triple decoction monster.