Metate grinding: what it is, how it's done and its uses

What is it?

Grinding on a metate is the oldest food-processing technique in Mesoamerica, present for at least 8,000 years. The metate, a rectangular stone carved from basalt or volcanic andesite, together with its hand stone (metlapil or roller), allows nixtamalised maize to be ground to make dough, cacao and spices to be ground for chocolate, mole pastes to be prepared and dried chillies to be crushed. The friction of stone against stone produces a fine, slightly warm grind that releases essential oils and develops aromas that no modern mill achieves. Although today it coexists with electric mills, in traditional kitchens the metate remains the tool of choice for blue dough, Oaxacan mole, table chocolate and other products where an artisanal texture and deep flavour are sought.

Origin and history

The metate is one of the oldest utensils of Mesoamerica, with archaeological evidence dated to 6000 BC in caves such as Tehuacán, Puebla, and Coxcatlán. Its basic form (a concave stone on three legs and a roller) remained practically unchanged for millennia, proof of its functional perfection. Pre-Hispanic codices such as the Mendoza and the Florentine depict women grinding on a metate, a central activity of the Nahua, Maya and Mixtec domestic economy. Fray Bernardino de Sahagún describes in detail the use of the metate in women's tasks (the temazcal and the metate were spaces of socialisation). After the conquest, the metate survived the introduction of European mills owing to its superiority for grinding cacao and nixtamal. The National Institute of Anthropology and History (INAH) has documented that the metate remains a living tool in towns of Oaxaca, Guerrero, Chiapas and Puebla, where it is carved by specialist artisans of generations.

Characteristic ingredients

The traditional metate measures between 40 and 70 cm long, 25-40 cm wide, is carved from a single piece of volcanic rock (basalt, andesite) and has three legs to tilt it forward. Its grinding surface is not smooth: it has a slight porosity that allows it to grip the grain. The hand of the metate (metlapil) is a stone cylinder of the same material, about 30-40 cm. Before use, a new metate is seasoned: salt, dried maize or rice are ground several times until the stone stops releasing particles and is fit for food. The technique involves kneeling in front of the metate and pushing the hand stone with the whole weight of the body, in long, firm movements. Different ingredients require different grinds: nixtamalised maize is ground with a little water at a time; toasted cacao is ground warm to release its fat; dried chillies are ground toasted with spices for mole. Grinding on a metate releases volatile oils and develops nuances that a mechanical mill does not produce.

Cultural significance

Grinding on a metate is a practice and symbol of traditional Mexican cooking, recognised by UNESCO as Intangible Cultural Heritage of Humanity in 2010. In indigenous communities, knowing how to grind on a metate is a central skill of the female culinary role, passed down from mothers to daughters over generations. The strength, rhythm and tactile sensitivity it requires are bodily learnings refined over the years. In Oaxaca, traditional cooks still grind mole on a metate for the great celebrations (weddings, patron-saint festivals), considering it the only authentic method. The table chocolate of Oaxaca and Tabasco is still made on a warm metate over embers. The metate also has a ritual value: it features on Day of the Dead altars and is passed down as a prized possession among women. Contemporary Mexican cooking has rescued the metate as a symbol of authenticity, present in haute-cuisine restaurants and gastronomic festivals.

Frequently asked questions

What is the difference between grinding on a metate and in a mill?

The metate grinds by friction and crushing between two porous volcanic stones, slightly warming the product and releasing essential oils and aromas that give a deep flavour. The industrial mill cuts and chops with metal blades or discs, yields faster but produces a more uniform grind that is flatter in flavour. The artisanal texture of the metate is irregular and complex.

What does food ground on a metate taste like?

It has a deeper, more aromatic flavour than the industrial version. Maize dough is left with toasted notes, is slightly grainy and has a better consistency for handmade tortillas. Metate chocolate develops intense toasted aromas and keeps the cacao fat integrated. Moles gain complexity from the release of the oils of chillies and spices.

How is a new metate seasoned?

Before the first use it must be seasoned: several batches of abrasive grains (coarse salt, raw rice, dried maize) are ground over days until the stone stops releasing grit. It is then rinsed, dried in the sun and ready. After each use it is cleaned only with water and sometimes a natural-fibre brush; never with soap or detergents.

Where does the metate come from?

The metate originates in Mesoamerica, with archaeological evidence of at least 8,000 years in the caves of Tehuacán (Puebla) and Coxcatlán. Today it is carved by hand in towns of Comonfort (Guanajuato), Puente de Ixtla (Morelos), Etla and the Mixteca (Oaxaca), where master stonemasons preserve techniques inherited from the pre-Hispanic era.