Caballito
The iconic small Mexican shot glass for tequila. Straight-sided, cylindrical, typically 30 to 45 ml; the name traces to a 19th-century charro horseback drinking horn.
The caballito ("little horse") is the iconic small Mexican shot glass: cylindrical, straight-sided, typically 30 to 45 ml, and usually made of thick clear glass. The name comes from a 19th-century practice among charros and hacendados who carried a small drinking horn (a cuerno) on a leather thong around the neck, into which tequila was poured: el caballito de tequila, "the little horseback vessel of tequila." Over time the cuerno became a glass, and the name stuck.
The caballito is a beautiful object, and most of the iconic mid-century Mexican tequila photography uses one. On the merits of the spirit, however, it is a poor tasting glass. Its straight sides concentrate ethanol vapor into the nose and bury the agave aromatics under alcohol burn. Since approximately the early 2000s, the premium tequila community has drifted toward the Riedel Ouverture Tequila glass for sipping work and reserved the caballito for the cantina shot, the bandera setup, and the chilled palate-cleansing pour. The vessel is, in short, iconic and cultural rather than analytical. The full vessel taxonomy lives in the culture chapter.