Essences

From Distillers Wiki

Essences are concentrated solutions of flavouring and colouring which are added to neutral spirits to mimic common spirits such as whisky, rum, brandy and gin, often to a high degree of accuracy. Essences can be bought at homebrew stores or made at home.

Experienced home distillers tend to regard essences as "cheating", preferring instead to pot distill spirits which rely on the flavor of the wash for character.