Metric measure of 100 litres. The hectolitre is not part of the International System of Units (SI), but is approved for use with the SI because it is a multiple of the approved litre. In viticulture, hectolitres are mostly used to indicate quantities of grape must (hl) or wine. In the production of quality wines, the maximum yield per wine-growing area or appellation or also smaller units/types of wine is defined in hectolitres (hl) of wine or in kilograms (kg) of grapes per hectare (yield per hectare). See also a list of other measures commonly used in viticulture under Hollow measures and wine production quantities.
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