An old fruit of the Americas
The avocado is native to Mesoamerica, and people in what is now Mexico have eaten it for a very long time. Botanists often group cultivated avocados into three broad horticultural races, usually called Mexican, Guatemalan and West Indian, and many modern varieties are crosses among them. The races differ in skin thickness, oil content, cold tolerance and size, and those differences show up in the kitchen.
The Hass avocado
The variety most people see in shops is the Hass avocado. It is named after Rudolph Hass, a California mail carrier, who patented a seedling in the 1930s; the original tree is generally described as a chance seedling of mixed Guatemalan and Mexican ancestry. Hass fruit has pebbly skin that turns from green to a dark purplish black as it ripens, a creamy, rich flesh, and a relatively long shelf life, which is part of why it travels well.
Mexico is a very large producer of Hass avocados, with Michoacan the best-known growing state. That is why Hass is the usual choice for avocado guacamole, sliced toppings and sauces across the country, even though it is a fairly modern commercial variety.
Other types you may meet
Beyond Hass, markets in Mexico may sell other fruit that look and taste different:
- Criollo or native types often have thinner skin, smaller size and a distinctive flavor. Some are eaten with the skin, and the flesh can be less oily than Hass.
- Smooth-skinned green varieties, such as Fuerte, Bacon or Zutano, which stay green when ripe and often have a lighter, milder flesh.
- Large green fruit from warmer regions, with watery, mild flesh, which some cooks use for slicing rather than mashing.
Names and availability vary widely, so a local seller is the best guide to what is in season.
Leaves as a seasoning
In several regions, the leaves of certain native avocado trees are used as a seasoning. They have a mild anise-like aroma, and cooks toast them lightly or crumble them into bean pots, meat and stews. Not every avocado leaf is suitable for this, and some are reported to be unsuitable for animals, so use leaves sold as a cooking ingredient rather than picking from a random tree.
Judging ripeness
Avocados do not ripen on the tree in the same way as many fruits. They mature on the tree and soften after they are picked, so shop fruit is usually firm. These cues help:
- Gentle pressure. Cup the fruit in your palm and press softly. A ripe avocado yields slightly. Pressing with your fingertips can bruise the flesh, so avoid prodding.
- Skin color for Hass. Dark, purplish-black skin usually suggests ripeness, but color alone is not reliable for green-skinned varieties.
- The stem cap. Flick off the small cap at the stem end. Green underneath usually means ripe and ready, brown suggests overripe, and a cap that will not budge suggests the fruit is not ready.
- Weight and rattle. A fruit that feels very light for its size, or whose pit rattles in a dry way, may be past its best.
These are guides, not guarantees, and cutting one open is the only certain test.
Ripening and storing
A firm avocado left at room temperature typically ripens over a few days, though timing depends on the fruit and the temperature. Putting it in a paper bag, perhaps with a banana or apple, tends to speed this up because those fruits release ethylene gas. Once ripe, keeping the avocado in the refrigerator slows things down.
A cut avocado browns when its flesh meets air. Lime juice, a tight cover pressed against the surface, or a thin film of oil can slow this, but none stops it completely. Browning is mostly cosmetic, but discard flesh that smells sour, has gone slimy or shows mold.
Choosing for the dish
Ripeness depends on use. Very soft, creamy fruit suits mashed sauces and spreads. Slightly firmer fruit slices cleanly for tacos, tortas and salads, and holds its shape better in a salad of tomato and onion. Fruit that is a little underripe can be used in a pinch, but the flavor is usually bland and the texture rubbery.
Avocado also works as a cooling counterpoint to chiles. A slice on a plate of hot enchiladas or soup, in the style of finishing toppings, is a common way to balance spice. Wash the skin before cutting, since the knife can carry surface bacteria into the flesh.
Pits, skins and seed myths
A common kitchen tip says leaving the pit in mashed avocado keeps it green. It only protects the surface it touches, so the result is limited. The pit is not usually eaten, and the large seed has uncertain safety as food, so it is simplest to discard it.