Malting

Steeping. The barley is soaked and drained in cycles of about eight hours for up to two days, raising its moisture from about 15 % to about 45 %.

Germination. The wet grain grows for four to six days at 16 to 19 °C. It is turned and aerated so that the rootlets do not mat and heat and carbon dioxide escape. The grain breaks down proteins and makes the enzymes that will later convert its starch: maltsters call this modification. Turning was done by hand for thousands of years and is now mostly mechanical.

Kilning. Hot air at about 80 to 90 °C dries the green malt to 3 to 6 % moisture. Growth stops and the enzymes become dormant, to wake again in the hot water of the mash. Higher kilning temperatures give darker, more flavourful malts, but can destroy the enzymes, so dark malts cannot be used alone.

How malt is dried shapes the beer. In Bamberg, the Schlenkerla brewery still dries its malt over an open beechwood fire, which gives rauchbier its smoke. The pale malt of the first Plzeň lager probably came from a kiln fired indirectly with coke, a technique possibly brought from England; brewing guides credit English malting techniques as much as lager yeast for the pilsner style.