Sal de gusano

Sal de gusano ("worm salt") is the traditional palate accompaniment to a slow Oaxacan mezcal pour. Despite the name, the gusano is not actually a worm; it is the larva of Comadia redtenbacheri, a moth (Lepidoptera: Cossidae) that lays its eggs in the heart of mature Agave salmiana and Agave angustifolia plants. The larvae feed on the agave heart and are harvested by hand, then dried, ground, and combined with toasted chile pasilla or piquín and coarse salt in roughly equal parts.

Two species are conflated under the gusano label in popular usage. The reddish "gusano rojo" is Comadia redtenbacheri, the species used for the salt and the one most associated with cultural prestige. The white "gusano blanco" is Aegiale hesperiaris, a hesperiid butterfly larva, sometimes the larva dropped into mezcal bottles for marketing effect. Neither is required by NOM-070-SCFI-2016A regulatory-standard NOM is a federal Mexican product norm. Unlike facility NOMs (4-digit identifiers of specific distilleries), a standard NOM defines the rules for an entire category of product: which raw materials are permitted, where the product may be made, how it must be processed, and how the bottle must be labeled. Standard NOMs are written as "NOM-XXX-SCFI-YYYY" where XXX is the standard number and YYYY is the year. NOM-070-SCFI-2016 (Mezcal). The official Mexican standard for mezcal production. Defines three production tiers (Mezcal Industrial, Mezcal Artesanal, Mezcal Ancestral) with specific equipment and method requirements for each, lists the permitted agave species and states, and governs labeling. Enforced by the Consejo Regulador del Mezcal (CRM).; neither indicates quality.

The salt is served on a small dish or scattered on a slice of orange, not used to rim a glass. The classical pour is: kiss the rim of the veladora or jícara, take a small sip, hold the spirit on the tongue, exhale through the nose, take a tiny bite of orange, taste a few grains of sal de gusano, take another small sip. The salt and orange are palate punctuation, not a chaser. The full service ritual is in the culture chapter.