In its basic state, barley is pretty much flavourless and almost impossible to brew with, but the malting process alters it in extreme ways, making it much more appropriate for brewing. To put it simply, malting is when the barley is tricked into sprouting and then dried; this process adds varying amounts of colour to the final malt. Malting gives the grain a crumbly texture, low gelatinization temperature, numerous enzyme cycles necessary for various brewing tasks, an available starch store, copious amounts of protein for yeast nourishment, and a husk which acts as the ideal filter to strain the sweet wort out at the end of the mash. Once we’ve finished, it also tastes amazing. It’s a tribute to the resourcefulness and tenacity of our earliest ancestors who transformed it from a shabby old grass to the honourable thoroughbred it is today.
Only seed-grade barley is used for malting. A large amount of germination is needed for excellent brewing. Just a small percentage of barley is used for brewing; the rest is used for animal feed. Maltsters also select barley which possesses other characteristics, such as uniform kernel size, protein content, and other details like glucans and SMM.
After a good soak, the next stage is steeping; this ups the moisture content in the grain from around 12 percent upwards of 40, moving it into an awakened state, preparing it for growth. This usually requires 2 to 4 days. The grain is then left in a process known as “couching,” where the grain begins to sprout.
Propelled by hormonal indicators sent by the germ, a small root emerges at one end of the grain. Within the husk, a shoot begins to grow. As malting continues, the shoot and roots maintain their growth; their length is an indication of the changes which are taking place inside. Throughout this time the grain is absorbing oxygen. Germination produces a large amount of heat, if safety precautions are not taken the malt will burn. Older methods of malting, for example floor malting, depends on a precise turning of the grain, whilst modern methods drive fresh air through the grain in provide oxygen and extract heat.
Barley Seed Anatomy
Barley kernel after the malting process
The structure of a barley seed exposes the complex structure which is ideal for brewing. In the meantime, enzymes are being hydrated and carrying out their duties. Proteolytic (protein-cutting) enzymes make holes in the protein membranes which cover the small bundles of starch which act as a food store for the seed. The result is that the kernel is transformed from a hard grain into a soft, chalky grain which will yield effortlessly in the malt mill. The amount of change is known as modification. Some historic malts were only slightly modified, this meant there were some hard ends which lingered. These malts are still obtainable today as specialty items.
Barley seed time lapse
This barley seed has been fully modified in the malting procedure. The kernel has transformed from a hard “flinty” texture to a soft, chalky consistency which will yield effortlessly to the malt mill. Yet, due to the hunt for productivity in the commercial brewhouse, completely modified malt is standard. It reacts wonderfully to basic infusion mashes, throughout which the malt is steeped at a single temperature, missing the step-ups which we commonplace in the traditional recipes. Many older mashing techniques such as decoction operate best with poorly modified malt, using them with modern malt can cause issues with the body and head of the final brew.