A number of Oaxacan distillers use only one distillation run to make their mezcals. Here’s how it works.

When you heat the liquid in a potstill, at about 170°F the alcohol starts turning to steam and rises up into the cap (or “hat”) on top of the still on its way to the tube leading to the condenser. But some of the steam tends to condense in droplets on the inside of the cap and fall back down into the distillate. Because these drops have already been distilled once, their liquid essentially goes through a second distillation when it gets heated back into steam again. This is called rectification, and it increases the percentage of alcohol in the steam.

Standard potstills at Los Danzantes The cap has been taken off the still in front.

For single-run distillation, the distiller replaces the normal cap on top of the still with a refrescadera (or refrescador, “cooler”) cap.

Here’s a photo of the inside of the refrescadera cap. In actual use, the open tube coming up from the still is connected to the long tube leading to the condenser. The distiller pours cold water into the refrescadera, which cools the cap and greatly increases the amount of condensation of the steam into droplets (which are falling back into the still and being redistilled) inside the cap and thus the alcohol content of the steam that is passing through to the condenser.

With a refrescadera, the distiller can achieve some 47-49% alcohol by volume in only one run, instead of the 55% he gets from double distillation. Single-run distillation preserves more of the soft round vegetal characteristics of the agave, and many mezcal drinkers prefer it.

This is the refrescadera used by Gabino Juárez in Rancho Viejo.

And the one at Sergio Juárez’ destilería in Amatengo.