is the cutting, threshing, separating, and cleaning of individual barley grains from the mature barley plant. Depending upon variety and climate conditions, barley grows from 12 to 48 inches tall. The tightly packed spikes or ears of seed kernels can take from 40 to 55 days to fully ripen after flowering and droop down when ready to harvest. Growers closely monitor and test mature plants for grain size, protein content, and moisture. For malting barley, the moisture content at harvest tends to be between 12% and 17%, whereby 12.5% is considered ideal. In the silo, the moisture level must be kept below 14%. The optimum protein level for brewing barley is between 9.5% and 11.5%.

Harvesting by “direct head cutting” involves cutting the ripened ears off close to the stem, high on the plant, to minimize debris. The crop is then threshed to separate the individual grains from other plant material and cleaned of foreign matter. Swathing, by contrast, involves cutting the plant low, leaving a short bed of stubble that supports the long interlaced stems and ears off the ground, where the crop is allowed to dry in the field before being gathered and threshed. Excessive handling, however, can break, crack, or abrade the barley kernel, rendering it useless to the malt house and brewer. Dry grain, properly stored, will last for months or even years.

Barley is still harvested by hand in very small fields and plots. Mechanized harvesting equipment—called combines—is often used that combines cutting, threshing, and cleaning into one process. This produces barley grains ready for immediate use or storage. In the United States, barley yields are often listed in bushels. This is a volume, not a weight measure, whereby 1 US bushel equals 35.24 l. This way of measuring yields make the result independent of the grain’s moisture content. In the metric world, on the other hand, yields are often given in kilograms or metric tons (1,000 kg) per hectare, whereby 1 hectare equals 2.47 acre. Because this is a weight measurement, two identical “yields” can be quite different depending on the barley’s moisture content. Consequently, there is no simple mathematical conversion formula between bushel yields per acre and metric-ton yields per hectare. For obvious reasons of climate, soil conditions, prevalence of pests and diseases, barley varietal differences, and agricultural methods, yields can range very widely across the world. In terms of bushels, yields of 100 to 150 bushels per acre of brewing barley are considered desirable. In much of Europe, farmers might consider yields of roughly 6 to 9 metric tons per hectare (6.6 to 9.9 US tons per 2.47 acres) satisfactory for winter barley or roughly 5 to 8 metric tons per hectare (5.5 to 8.8 US tons per 2.47 acres) for spring brewing barley.