Mexico — pan-regional, though the name is most associated with Norther Mexico and Tex-Mex cookery. Raw tomato salsa preparations are documented throughout Mexico under various regional names.
Pico de gallo (literally beak of the rooster — a name whose origin is debated; possibly referring to the pecking motion of dicing or to the appearance) is the raw, uncooked tomato salsa of Mexico — tomatoes, white onion, fresh jalapeño or serrano, cilantro, lime juice, and salt. The technique is entirely in the knife work and timing: all ingredients must be cut to a uniform small dice (approximately 5–6mm), and the salsa must be prepared as close to service as possible. The critical technique is salt management: salt draws water from the tomatoes through osmosis, creating a watery, diluted salsa within 20 minutes of preparation. Two approaches: (1) prepare and serve immediately for the freshest, brightest flavour; (2) salt the diced tomatoes separately, drain off the expressed water, then combine with the other ingredients for a salsa that holds better. The tomato-to-onion-to-chile-to-cilantro ratio is the stylistic signature — some preparations are tomato-dominant and mild; others feature equal volumes of all four components.
At its best, pico de gallo is a celebration of ripe tomato: the sweetness and acidity of the raw fruit is amplified by lime, balanced by the sharpness of raw onion and the heat of fresh chile, and brightened by cilantro.
Uniform dice: all components should be approximately equal size for textural consistency and balanced flavour in each bite Do not season until immediately before service or after 20-minute rest-and-drain Ripe, flavourful tomatoes are essential — pico de gallo cannot rescue flavourless tomatoes Lime juice is the acid, not vinegar — the flavour difference is significant
For service pico de gallo that must be prepared in advance, use a mixture of Roma and cherry tomatoes — cherry tomatoes hold their structure longer after cutting Some Mexican cooks add a small amount of cucumber (peeled, seeded, diced) to pico de gallo for additional crunch and freshness The white onion should be as fine as possible — large onion chunks overwhelm the balance; a 3–4mm dice is ideal
Preparing more than 1–2 hours in advance — the tomatoes release water and the salsa becomes diluted and limp Using under-ripe tomatoes — the entire purpose of the preparation is the fresh flavour of raw tomato Over-cilantro — cilantro should accent, not dominate; the preparation is about tomato balance
Rick Bayless, Authentic Mexican; Roberto Santibañez, Truly Mexican; Pati Jinich, Treasures of the Mexican Table