The malting process remains a 3-step process: steeping, germination and drying:
During steeping, water is absorbed by the raw barley kernel and germination begins. Steeping starts with raw barley that has been sorted and cleaned, then transferred into steeped tanks and covered with water. The raw barley alternates between being submerged and drained for 40-48 hours until it increases its moisture content from 12% to 44%.
The absorbed water activates naturally existing enzymes and stimulates the embryo to develop new enzymes , which break down the protein and carbohydrate matrix that encloses starch granules in the endosperm, opening up the seeds starch reserves, and the newly developed hormones initiate growth. Steeping is complete when the barley has reached a sufficient moisture level to allow uniform breakdown of the starches and proteins.
The ‘steeped barley’ is transferred from the steep tank to the germination compartment. Germination, which began in the steep tank, continues in this compartment where the barley kernel undergoes modification, referring to the breakdown of the protein and carbohydrates, resulting in opening up the starch reserves. Good modification requires the barley to remain in the compartment for 4-5 days. Germination is controlled by drawing temperature-adjusted, humidified air through the bed. Turners keep the bed from compacting and rootlets from growing together, or felting.
Germination is halted by drying. If germination continued, the kernel would continue to grow and all of the starch reserves needed by the brewer would be used by the growing plant. Base and standard malts are kiln dried, typically with a finish heat of 80 – 90 degrees Celsius for 2-4 hours. This develops flavours ranging from very light malty to subtle malty. Specialty malts are dried in a kiln at a higher temperature for longer periods of time. Varying the moisture level + time + temperature of drying results in the different flavor and color characteristics of each specialty malt.