malting
Malting
Persuade barley to begin germinating and then stop it, so the grain develops starch-converting enzymes and its starch becomes accessible.
What is actually happening
Steeping raises the grain’s moisture to around 45%, which triggers germination. The embryo begins to grow and releases hormones that induce the production of amylases and cell-wall-degrading enzymes.
Germination is allowed to run for several days at controlled temperature and humidity. Cell walls and the protein matrix surrounding the starch granules break down — this is modification, and how far it is taken determines what kind of mash the brewer will need.
Kilning arrests the process by drying the grain. Kilning temperature sets everything downstream: gentle drying preserves enzymes and produces base malt, while hotter kilning develops Maillard colour and flavour at the cost of enzyme activity.
Typical conditions
| Duration | 5–10 days |
|---|---|
| Scale | A commercial-scale operation |
Ranges, not targets. These describe what is usual across the styles and breweries that use this step, and a value outside the range is a decision rather than an error.
Questions
Why malt the grain at all — why not just use barley?
Raw barley has no usable enzymes and its starch is locked inside an intact protein and cell-wall matrix. Malting creates the amylases that will convert the starch and breaks down the structure holding it. Unmalted grain can be used as an adjunct alongside malt, because the malt supplies enough surplus enzyme to convert both.
Related steps and concepts
- Kilning — The step that ends malting and sets the malt’s character.
- Milling — What happens to malt at the brewery.
- Modification — How far germination was taken.
- Diastatic power — The enzyme capacity malting creates.
Also at the malting stage
See the whole process in order on how beer is made.
Last reviewed 2026-08-16.