The majority of barley is grown for feed purposes, either animal or human. Grain destined for livestock or human feed tend to have higher protein content. These barleys can also be hulled or hulless. Some new hulless cultivars now give more digestible, higher-protein feed, which is especially valuable for the pig and poultry sectors.
The Barley crop is very diverse and can therefore be classified in several ways. The most used classifications are by ear type, grain use and awn characteristics.
This is the number of rows of grains on the ear. One way the genetic diversity in barley expresses itself is in the number of rows of grains that develop on the ear/spike. Wild barley is two-row whilst the dominant cultivated barley is the six-row type.
- Six-row barley can produce 25-60 grains
- Two-row barley produces 25-30 grains.
- Four-row barley is a loose six-row barley.
Barley grains are either rolled, ground, flaked or pelleted for feed. The by-product following the malting process can also be used as a feed (often referred to as Brewers Grains). Finally barley can also be grazed or cut and fed as a forage crop. When used for human food it will be as pearled barley or barley flour. Prior to the 1500's barley flour was the main ingredient for breads.
The second most important use of barley is for malt. Malt is 60-65% undegraded starch and is used to produce beer, distilled alcohol, malt syrup, malted milk, flavorings and breakfast foods. The varieties suited to this are often lower yielding, but can be sold at premium prices over the feed varieties. Malting is the process of encouraging the grains to sprout in a controlled way and then stop. There are three key stages:
- Steeping - is the first stage of the malting process and typically takes up to three days. The moisture content of the barley is raised from 2% to 45%. The grain then starts to germinate which produces heat and carbon dioxide (respiration). By the end of this first stage all the grains should have started to germinate.
- Germination – is the second stage of the process. Germination continues for another five days. The germinating grains are cooled, carbon dioxide is removed, and they are continually moved to keep the roots from growing into a matt.
- Kilning – is the third phase of malting and it is when the grain is dried down to between 3 and 6% moisture which stops the germination process. This is achieved by blowing large amounts of hot air through the grain. By varying the air flow and temperature, malts of different colours and flavours are produced. At the end of this stage the malt is cool and all the tiny roots have been removed. The final malt is categorized according to its profile before being despatched.
Another way that has been used to classify barley is by describing the awns:
- Long awned
- Short awned
- (Normal) hooded
- Elevated hooded,
- Subjacent hooded
- Long awned in central row, and awnletted or awnless in lateral rows
- Short awned in central row, and awnletted or awnless in lateral rows
- Awnless or awnletted in central and lateral rows
- Elevated hoods in central row, and awnless in lateral rows