The barley grain undergoes the malting process to make beer.
Malting is a process used on various cereal grains, germinating them by immersing them in water and then heating them to slow down the germination process. It is commonly made from barley, for a wide range of purposes, most notably brewing. The process is ancient, with its roots hidden in the mists of time, but it was definitely in use by the time of the ancient Egyptians thousands of years ago.
barley grains
Probably the early malting was carried out in a very simple way. It seems that the Egyptians filled a basket with grain and placed it in a well until it was submerged in water. They would then lightly lift it out of the water so that it would begin to germinate. By changing the height at which the malt basket was held, they could change the speed at which the process took place. After it had sufficiently germinated, they would pull it out and spread it on the ground in the sun, letting the sunlight dry the grain.
Many homebrewers use a wort chiller to lower the temperature.
Eventually this process became too limited to meet the demand for malt for beer production in central Europe many centuries later. For this process special buildings were created, known as malting. The first malt plants were found on a hill near a stream, and barley or some other grain was placed on top of the building and soaked in the water. It was then left on the ground to germinate, and as heat was generated it traveled farther, until it reached the end of the room. From there, it was transferred to wheelbarrows and taken to an oven, where it was dried, moving from time to time to prevent gases from accumulating.
It wasn’t until powerful sources of energy emerged, in the form of steam and then electricity, that the malting process changed again. Although previously it could only be done during the colder months, with energy sources it became possible to artificially cool the malts to keep them at the ideal temperature throughout the year. Subsequently, new technologies such as conveyor belts, perforated floors and lathes were added to further facilitate the process, making possible the mass production necessary for modern uses.
The purpose of malting a grain such as barley is to change the structure of the grain to make it better suited for a particular purpose. One thing that happens when grain malt is created is that they create large amounts of sugar, mainly maltose, in their bodies. This sugar is used, for example, during the brewing process as the main leavening agent. Without sprouting, the energy stored in the grain seed is too trapped to be of much use to a brewer or cook, so this process forces partial sprouting to release all that energy.
On a deeper level, when a grain begins to sprout, it releases a variety of enzymes and creates new enzymes that break down and modify the endosperm of the grain. This endosperm is a matrix of starch, consisting of proteins and carbohydrates, and when enzymes break it down, they release starch granules, pentosans, and beta-glucans. Depending on how much is desired, the malting process can continue for some time or stop quickly.