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Mashing

Mashing · conversion, temperature, and enzyme management

The mash is where starch becomes sugar. For GF brewers, it is also where most of the technical variables that separate good beer from disappointing beer are decided.

Mashing is enzymatic in nature — the right enzymes, at the right temperature, in the right pH environment, converting starch into fermentable sugars and unfermentable dextrins that together define the beer's character. Gluten-free grains complicate every one of those variables: lower diastatic power, higher gelatinization temperatures, different pH buffering, and grain-specific conversion challenges.

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Why GF Mashing Is More Variable

With a barley mash using well-modified pale malt, a single-infusion rest at 150–158°F covers most styles reliably. The grain's enzyme content is high, gelatinization temperatures are within the normal infusion range, and pH buffering is predictable.

GF grains shift each of those defaults:

  • Sorghum gelatinization temperature (165–175°F) is above the normal enzyme active range — raw sorghum starch cannot be converted in a standard infusion mash without decoction or pre-cooking
  • GF malts vary widely in diastatic power — some supply enough enzymes for self-conversion, others do not
  • GF worts buffer pH differently than barley wort and can drift during the mash
  • Some GF grains produce high beta-glucan levels that increase wort viscosity

Understanding each variable independently lets you design a mash that works, rather than troubleshooting batch failures.

What This Section Covers

  • Enzyme Conversion — alpha and beta amylase activity, diastatic power in GF malts, and when to use exogenous enzymes
  • Temperature Programs — single infusion vs. step mashing, gelatinization temperature by grain, and how rest temperatures shape body and fermentability
  • pH Control — target pH range, GF wort buffering behavior, and how to adjust without overcorrecting
  • Decoction Approaches — when and why decoction is needed for sorghum and high-gelatinization adjuncts
  • Mash Challenges — stuck mash, poor conversion, viscous wort, and what each problem looks like

Source Notes

Mash chemistry and enzyme activity data based on brewing science literature. GF-specific conversion behavior from commercial malting quality reports and craft GF production records.