🥃 Distillation

Distillation (distilling) is a way to make a strong drink from a fermented liquid: it is heated, and ethanol, which boils at 78.2 °C, that is, before water, evaporates first; the vapor is cooled and collected. This is how whisky, brandy, rum, vodka and gin are made from wash, wine or cider.

Pot still and column. According to Difford's Guide, the simplest apparatus is the pot still (alembic), which works in batches: charge it, distil it, empty it. A column still works continuously and produces a stronger and purer distillate; the two-column still was invented by Robert Stein in 1826, and Aeneas Coffey patented an improved version in 1831.

Heads, heart and tails. The volatile "heads" with acetaldehyde and methanol come first and are discarded; then comes the "heart", which is kept; at the end come the "tails" with fusel alcohols, which are often added to the next batch. Methanol boils at 64.7 °C, close to ethanol, so precise cutting is important for safety. The copper of the still binds sulfur compounds.

Law and styles. Single malt Scotch whisky is distilled only in pot stills, usually twice, and below 94.8% ABV. Regulation (EU) 2019/787 requires fruit distillates to be distilled below 86% ABV to preserve the flavor of the raw material, and vodka is made from agricultural-origin spirit at 96% ABV or higher. Cognac is distilled twice in a Charentais alembic.

Why this matters to you. The lower the distillation strength, the more of the raw material's aroma remains in the drink; high strength yields neutral spirit. Home distillation without cutting off the heads is dangerous because of methanol: about 10 ml can cause blindness. The WHO reminds: there is no safe dose of alcohol.