Scotch grain whisky is usually made from a combination of malted barley and either maize or wheat. The starch in the non-malted cereals is released by pre-cooking and converted into fermentable sugars. The mashing and fermentation processes are similar to those used for malt whisky. The wash is distilled in a Coffey or Patent Still, named after its inventor Aeneas Coffey. It has two tall columns - a rectifier and an analyzer. Cold wash is pumped in at the top of the rectifier and meets steam. The alcohol is cooled, it then condenses and flows away as scotch grain spirit. The distilled grain spirit is lighter in character and aroma than most malt whiskies and therefore requires rather less time to mature. The vast majority of matured grain whisky is used for blending.