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Barley Malts
Malting
Malting serves the purpose of converting insoluble starch to soluble starch, reducing complex proteins, generating nutrients for yeast development, and the development of enzymes. The three main steps of the malting process are steeping, germination, and kilning.
Barley Steeping
Steeping begins by mixing the barley kernels with water to raise the moisture level and activate the metabolic processes of the dormant kernel. The water is drained, and the moist grains are turned several times during steeping to increase oxygen uptake by the respiring barley. Generally, the barley spends about 40 hours in tanks of fresh, clean water, with three intervals during which the water is allowed to drain. Draining is done to remove dissolved carbon dioxide and to reintroduce oxygen-rich water. Steeping is complete when the white tips of the rootlets emerge, which is known as chitting. At this point the grains will have swollen one and one-third times their original size.
Barley Germination
In the next step, the wet barley is germinated by maintaining it at a suitable temperature and humidity level until adequate modification has been achieved. Germination is done on floors, in drums, or in boxes. Floor malting is an old process in which the chitted malt is spread on the floor to a height of 10 to 20 cm. Germination in drums is still done, but is not very economical; consequently, only a few plants still use this system (19).
Malt Kilning
The final step is to dry the green malt in the kiln. Malts are kilned at different temperatures. The temperature regime in the kiln determines the color of the malt and the amount of enzymes which survive for use in the mashing process. For an example of barley malt that has been kilned, refer to Figure 2.1. Low temperature kilning is more appropriate for malts when it is essential to preserve enzymatic (diastatic) power. These malts are high in extract but low in coloring and flavoring compounds. Pilsner and pale ale malts are examples of malts kilned at low temperatures. Malts kilned at intermediate temperatures, such as Munich and Vienna malts, are lower in enzymes but higher in coloring and flavoring compounds. Malts kilned at high temperatures, such as crystal and chocolate malts, have little if any enzymes, thus are lower in extract.
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