To make beer, brewers use water and barley to create a sweetened liquid (called the wort), which they flavour with hops, then ferment with yeast. The basic process may be simple but the execution is highly sophisticated. The three most important stages are malting, brewing and fermentation - followed by maturation, filtering and bottling.
Malting is the process of readying barley to be used in brewing. Barley cannot be used to create the wort in its normal state, because the starch in its floury kernel is insoluble. So the grain is steeped in water, then spread out on racks until rootlets appear. The germination process produced enzymes which break down the starch. Once the plumule below the husk grows to three quarters the length of the grain, germination is halted by drying the green malt, as the barley is now called, on metal racks in the kiln house at 50° C. The temperature is then raised to 85°C for a light malt, or higher for a dark malt. The malt shoots are removed for cattle feed, and the dried malt is stored in silos. Although malted barley is the primary ingredient, unmalted corn, rice or wheat are sometimes added, to produce different beer flavours.