What is the difference between single malt and blended whisky?

Single refers to the distillery, not the cask. A single malt is distilled at one distillery; how many casks were blended together afterwards does not matter for that designation. A bottle of Glenfarclas 12 Year Old contains whisky from dozens of casks and is still a single malt.

The second requirement is the raw material: only water and malted barley, without other grains. The third is the method: distilled in pot stills, the bulb-shaped copper stills in which one batch at a time is distilled. These three requirements are laid down like this in the Scotch Whisky Regulations 2009.

A blended Scotch is a blend of at least one single malt and at least one grain whisky. The grain whisky comes from a continuous column still and may be made from grains other than barley; it provides the light, soft part. The single malts bring the flavour and the character.

The ratio is the blender’s secret. A brand like Johnnie Walker keeps that ratio the same year after year, while the casks it draws from are constantly changing. That is precisely what a blend is made for: the same taste, every bottle, every year.

In een blended malt zit geen graanwhisky. Het is een mengsel van twee of meer single malts uit verschillende distilleerderijen — alleen gemoute gerst dus, maar niet uit één huis. Een blended Scotch bevat wel graanwhisky.

On older bottles, blended malt sometimes still says «vatted malt» or «pure malt». Those terms have no longer been allowed on Scotch whisky since the 2009 rules. If you come across them, you are holding a bottle from before that time, or a whisky from outside Scotland.

No, they are categories and not quality marks. The law says nothing about quality; it only says where the whisky was distilled and from what. There are mediocre single malts and excellent blends, and the other way round.

What does differ is the intention. A single malt shows what one distillery can do with one raw material; the character of that house comes first, with all the outliers that entails. A blend is built on repeatability. Anyone looking for the distinctiveness of a region or a house ends up with the malts; anyone who wants a consistent taste ends up with the blends.

Scotch must mature for at least three years in oak casks of no more than 700 litres, and that maturation must take place in Scotland. Below 40% alcohol it may not be called Scotch. Both requirements apply to every category, from single malt to blended grain.

An age on the label always refers to the youngest whisky in the bottle. If a blend says 12 years, then the youngest grain whisky in it is also at least twelve years old.