Tahona

The tahona is a large stone wheel, typically two to three meters in diameter and carved from volcanic basalt or limestone, used to crush cooked agave in a shallow circular pit (also called a tahona in some regions, or molino de piedra). The wheel turns on a central pivot driven by a draft animal (historically a mule or donkey) walking the circumference of the pit, or, since the mid-20th century, by a small tractor or electric motor. The crushing action separates juice and fiber from the cooked agave heart, the piña, in a slow, mechanically gentle process that takes hours rather than the seconds a modern roller mill takes.

The tahona sits in the center of the artisanal-versus-industrial debate in both tequila and mezcal. A tahona-milled wash carries more long-chain fibers, pectins, and esterified compounds into fermentation than a roller-milled or diffuser-extracted wash; the resulting spirit is fuller-bodied, with more vegetal and earthy weight in the mid-palate, at the cost of yield and consistency. Under 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)., milling by tahona, mallet, or hand is one of the permitted methods for the Mezcal Artesanal class, and is the only mechanical option for Mezcal Ancestral (alongside hand or mallet). In tequila, tahona-milled product is a small but identifiable premium-segment claim; the milling-architecture comparison is walked in the distillation chapter.