Vodka production: Base spirit
Ethanol alcohol distilled to more than 95% purity is commonly called neutral spirit. The term used in this context refers to the spirits' lack the flavour. More flavour would have been present if the mash ingredients were distilled to a lower level of alcoholic purity.
It is usual to indicate the type of base ingredient used to make a neutral spirit. For example grape, grain, molasses become grain neutral spirits, grain neutral spirits and molasses neutral spirits.
As continuous column still technology became more sophisticated, a new class of distillers who specialised in producing neutral spirit emerged. These distillers are sometimes referred to as agricultural distillers. The vast investment required to set up a new column still is simply not viable for small distillers who do not have a market for the vast volumes of alcohol such stills are capable of producing.
Two-tier distilling was around even before the column still was invented. It is more efficient to ferment and distill grain near where it is harvested and to ship the high strength alcohol than it is to ship grain or molasses. The high quality and low cost of neutral alcohol produced by large specialist distillers has led most vodka producers to buy in their base alcohol rather than produce it themselves. Many then redistill the base alcohol to further rectify it using column or pot stills.
The vodka producer can import high strength neutral spirit and dilute it with water, bottle and then distribute to his local market.
It is not just the economics of shipping and the inability for small landmass countries such as the UK to meet their grain needs that has driven two-tier distilling. Governments wanting to control and monitor the payment of taxes due on alcohol have often legislated to force distillers to buy in their base alcohol. In the UK such legislation that prevented neutral alcohol being made at the same distillery where such alcohol was redistilled to make gin was only recently overturned. Even today, only a handful of vodka distilleries in the world produce their own base alcohol from grain on the same site where finished vodka is produced.