Single Grain Whisky

Grain whisky is usually made from 10-20% malted barley and then other unmalted cereals such as maize or wheat, so differs from Malt Whisky where 100% malted barley is used. 

The still used to make grain whisky, a Coffey still named after its inventor Aeneas Coffey, is also different and can be run continuously rather than in batches when making a single malt. It has two tall columns - a rectifier and an analyser and it produces Scotch grain spirit at about 94% alcohol by volume. The distilled grain spirit is lighter in character and aroma than most malt whiskies and therefore requires  less time to mature. The bulk of matured grain whisky is used for blending.

Distillers discovered that if you leave a grain whisky maturing for longer than 20 years the flavours are extremely delicate and sweet. A single grain is the top end of grain whisky production where the whisky has been made at only one grain distillery and not mixed with another.