Tequila from the Ground Up - Part V
In broad strokes, distillation is the use of of temperature and time to separate alcohols and certain congeners (aroma and flavor components formed in fermentation) from water and other undesired elements. Since ethyl alcohol, water, and every other chemical compound have unique boiling or evaporation points, gradually increasing the temperature of the mosto muerto (the end result of fermentation), separates the scores of different compounds as they vaporize at different points in time. Those vapors then come into contact with some kind of cooling condenser, bringing them back into liquid form. The various compounds are then either discarded (“cut”) or collected.
Distillation can be carried out in two kinds of stills - column stills (often referred to as “continuous” or “Coffey” stills) or or pot stills (also called “alembics” or “discontinuous” stills). Undesirable compounds tend to be found in the “heads” (the beginning of distillation) or the “tails” (the end of the process). While science has made distillation more precise than it once was, there is a still a lot of art to it. Three different distillers working with the same mosto muerto, for instance, could “cut” their heads and tails in slightly different places, creating three distinct tequilas that would all be certifiable and safe for consumption, but with somewhat different flavor profiles.
An interesting side note - tequila and other agave spirits are unique in the world in that the majority of the methanol (“bad alcohol”) is found in the tails, rather than the heads.
It is a common misconception that tequila must be double distilled. The Norma Oficial de Tequila states simply that tequila must be between 35-55% alcohol by volume. In a pot still process, at least two distillations will generally be required to reach this level of alcohol. In these processes, the first distillation (“destrozamiento”) creates a low-alcohol liquid called “ordinary,” and the second (“rectificación”) creates still-strength tequila blanco. A single pass through a column still can result in a tequila of 55% ABV.
Still-strength blanco can be bottled directly, diluted and filtered, or sent to age in oak. We will address these steps in further blogposts.
Please join us for a tequila tasting the next time you visit Tequila - we’ll meet you wherever you are on your education and journey. Make a reservation at La Cata today.