A very old tool
The metate is a slab of stone used for grinding, paired with a handheld stone called a mano (literally “hand”). The word metate comes from Nahuatl. Archaeologists have found grinding stones of this kind across Mexico and Central America over many thousands of years, and they remain in use in some homes and communities today. They sit near the beginning of the story of Mexican cooking, because they made it practical to turn dried or soaked grain into dough.
Most metates are carved from volcanic rock, which is hard and has a slightly rough, porous surface. Some stand on three short legs and slope gently downward at one end, while others are simpler flat or dished slabs. The mano is a long, rounded or flattened stone, held in both hands.
How grinding works
The cook kneels or stands at the stone, depending on its height, and pushes the mano forward and back across the slab with the weight of the upper body. The ingredient is crushed between the two stones, and the slope helps the ground material gather at the lower end. Done repeatedly, the motion turns coarse ingredients into a paste or fine powder.
It is physical work. Grinding enough corn for a family’s tortillas could take a considerable time in the past, and the labour was traditionally done by women in many communities. Treat this history with respect: the metate is not merely a tool but part of a long domestic and cultural tradition.
Grinding corn
Dried corn is not ground raw into masa. It is first cooked with an alkali, usually slaked lime or wood ash, then rinsed, a process explained in the article on the nixtamalization process. The softened kernels, called nixtamal, are ground on the metate into a smooth, sticky dough, adding water in small amounts. This dough is what the guide to masa dough describes, and it is the base of tortillas and tamales.
Hand-ground masa tends to be coarser and may have more varied texture than a machine-ground one. The cook may grind it more than once to reach the desired fineness. Today, most households use a mill or buy ready-made dough, and masa harina is a dried alternative.
Grinding cacao and other ingredients
Roasted cacao beans, with sugar and spices, were traditionally ground on a warm metate. The warmth, sometimes from a small fire beneath the stone or from hot coals, helps the cocoa fat soften and turns the beans into a paste that can be shaped and dried into tablets. This is the process behind stone-ground chocolate, and it gives the finished tablets a slightly grainy texture. Some makers still work this way, though most commercial chocolate is made with machinery.
The metate also grinds:
- dried or toasted chiles for sauces
- sesame, pumpkin and other seeds for sauces
- spices such as cinnamon and allspice
- coffee, sometimes
- beans and other ingredients for pastes
Complex sauces, such as those in the family of mole sauce, have traditionally been ground on stone, with each ingredient worked separately, although they are now more often processed in blenders or in mills.
Preparing a new metate
A new metate is usually rough and may release grit, much like a molcajete. A common method of seasoning is to grind raw rice or dried corn until the powder is no longer grey, discard it, rinse, and repeat. Some cooks also grind garlic or salt. Methods differ between regions and families, and stones sold by specialist makers may come with their own instructions.
Care
Wash with water and a brush and avoid soap, which the stone can absorb. Let it dry fully in the air. Stone is very heavy, so a metate is hard to move, and it should sit on a stable base. Re-roughening, or “picking”, the surface is sometimes done by skilled craftspeople when it becomes worn smooth, which is a specialist task.
Metate, molcajete, and mill
It is easy to confuse the metate with the molcajete. The metate is a large flat slab worked with a rolling push of a hand stone, mainly for grinding and spreading materials into a paste. The molcajete is a bowl with a pestle, which crushes more than it grinds. Both are made of similar stone, and many kitchens that kept one also had the other.
Why it persists
Machines are faster, and most people now use them. Still, the metate remains meaningful for a few reasons: the texture some cooks prefer, ceremony and cultural continuity, and a lack of electricity or mills in some places. If you try one, expect it to take time, and take care of your back and wrists, since the motion is tiring. Take breaks, and do not overload the stone.