If you don't count pina coladas as sustenance, coconut milk isn't much of a staple in this country. But for the third of the world's population who live in the tropics, it's more important than cow's milk is here. It is fundamental to soups, stews, roasts, puddings, cakes, candies and beverages in Southern Asia, the South Pacific, West Africa, Brazil and the Caribbean. Coconut milk even takes the place of water for making rice.

It is difficult to say how the use of coconut milk started. There is only one species of coconut palm, and since coconuts float, it implanted itself around the tropical beaches of the world long ago.

Coconut milk is not the liquid inside the coconut, it is rather the liquid wrung from the grated and soaked meat. It has many properties of cow's milk: the cream rises to the top when it sits, it must be stirred when it comes to a boil, and the fat is chemically closer to butterfat than vegetable fat.

While there are good canned coconut milks on the market, it's better to make your own, even for pina coladas.

To make your own, first puncture two of the three eyes of the husked coconut, and drain and reserve the liquid.

Bake the coconut at 375 degrees for 15 minutes, then split it with a hammer. The meat should fall away from the shell. (Stubborn pieces may be pried loose with a knife.) Pare the brown skin, break up the large pieces and blend them with the reserved liquid in a blender or food processor. Add one cup of boiling water and allow the gratings to soak for an hour. Then strain the liquid through cheesecloth, twisting it tightly to extract every drop.

The milk can be kept in a jar in the refrigerator for up to a week. (Cooks where coconuts are a staple often reinfuse the gratings with hot water for dishes such as plain rice that require only a light flavoring.)

If you can't imagine yourself following the instructions above, there are flavorful, reasonably priced brands of coconut milk (unsweetened) on the market from the Philippines, Thailand, Singapore and Samoa.

The richest at the most reasonable price is Chaokoh, a Thai brand that is nearly half cream. Chef's Choice, also Thai, is very good, as is Yeo's from Singapore, the only one I found without preservatives.

For most dishes you will want to blend the milk with the cream before adding, although some desserts call only for the cream.

Store unused coconut milk in a jar in the refrigerator as you would the fresh. RICE WITH TOMATOES, CHILIES AND COCONUT MILK (West Africa) (4 servings)

2 tablespoons peanut or olive oil

1/2 cup chopped red chili peppers

1/2 cup finely chopped onion

1 cup uncooked long-grain rice

1 1/2 cups fresh coconut milk or the equivalent canned

2 medium sized tomatoes, peeled, seeded, and finely chopped or 2/3 cup chopped drained Italian canned plum tomatoes

1 teaspoon salt

1 teaspoon freshly ground white pepper

Heat oil in a heavy skillet over medium heat. Add chilies and onion, and cook, stirring, for 3 to 4 minutes. Add rice and stir for 2 minutes, then stir in coconut milk, tomatoes and salt, and bring to a simmer. Cover skillet tightly, reduce heat to low and cook for 20 minutes, or until all the liquid has been absorbed. Remove from heat, stir in pepper. Cover again and allow the rice to sit for 10 minutes before serving. Fluff with a fork before serving.