What is malt? In brewing it specifically refers to cereal grains that have been “malted”. Malting is the process of germinating barley and other cereal grains to release enzymes necessary for starch conversion. This process is halted by kilning the grain (122-158f) so that it is dried, locking in the enzymes at their most usable point. The final water content is reduced from 40-50% by weight to 3-8%, which is important to long term storage.