Aqua Vitae

Aqua Vitae was made by fermenting grain mash or grape wine with yeast to produce a dilute alcoholic liquid, then distilling that liquid in an alembic to concentrate the more volatile alcohol and separate it from water and other components, a technique that spread through medieval Europe from earlier distillation traditions and became closely associated with monastic and university medical schools by the thirteenth century. Early distillers recognized quickly that a single distillation gave a relatively weak spirit and that repeated distillation, called rectification, raised the alcohol's strength and purity further, up to the practical limit imposed by the fact that a water-ethanol mixture cannot be distilled to complete purity by ordinary heating alone, a limitation only explained by modern azeotrope chemistry centuries later. The resulting spirit burned with a visible flame when ignited, a property that gave it the alternate name aqua ardens, burning water, and that was taken as visible proof of its fiery, vital nature.

Physicians of the period, working within a medical tradition that valued warming, vitalizing remedies, prescribed aqua vitae as a tonic, a preservative for other medicines, and a treatment for a wide range of complaints understood as arising from cold or weak vital spirits, a therapeutic reputation that outlasted the specific medical theory behind it and that helped establish distilled spirits as a permanent part of European pharmacy and, soon after, of ordinary drinking culture.

Aqua Vitae is identified as distilled ethanol, more precisely an ethanol and water mixture whose concentration depended on how many times it had been redistilled, an identification with no real scholarly dispute attached to it since the fermentation and distillation processes described in the historical sources are essentially the same processes, using more primitive equipment, still used to make distilled spirits today.

What changed between the alchemical period and the modern understanding was not the identity of the substance but the account of why it worked and why it had limits: modern chemistry explains both the flammability of concentrated ethanol and the practical ceiling on how pure a distilled spirit can become through ordinary distillation, the azeotrope formed between ethanol and water that prevents further separation by heat alone, a limit early distillers ran into empirically without being able to say why repeated rectification eventually stopped yielding a stronger product. Reaching a genuinely anhydrous, water-free spirit required techniques beyond simple redistillation, chemical drying agents among them, that were only fully worked out well after the alchemical period, though the practical spirits distillers achieved by careful rectification alone were strong enough for essentially every purpose the period needed.