A distillate, or akvavit, is an alcoholic product derived from the distillation of a sugary compound left to ferment for different times and coming from the vegetable world: cereals, herbs, fruits, wine or marc.
The alcoholic result will be composed of numerous substances, including esters and various types of alcohols with different boiling temperatures.
When we speak of heads we mean all those extremely volatile substances produced by alcoholic fermentation such as acetone, acetic acid, and sulfur dioxide derived from yeasts. Here, moreover, there is a large part of the methanol, which is produced from pectins, has a boiling temperature of 64.5 C° and can therefore be reduced by cutting them (ie discarding the first drops produced by the pot still).
The tails, however, correspond to the higher alcohols and are fatty and oily substances such as glycerine, which can also be eliminated by precise distillation methods.
In this way we have only the central part of the distillate, which contains the true soul, that is the spirit of the raw materials used.