Coconut milk is a sweet, milky white cooking base derived from the meat of a mature coconut. The color and rich taste of the milk can be attributed to the high oil content and sugars. In Malaysia, Brunei and Indonesia coconut milk is called santan and in the Philippines it is called gata.
In Thailand it is called ga-ti and used in many of the Thai curries. In Brazil, it is called leite de coco (literally, coconut milk). It should not be confused with coconut water (coconut juice), which is the naturally-occurring liquid found inside a coconut.
Two grades of coconut milk exist: thick and thin. Thick coconut milk is prepared by directly squeezing grated coconut meat through cheesecloth. The squeezed coconut meat is then soaked in warm water and squeezed a second or third time for thin coconut milk.
Thick milk is used mainly to make desserts and rich, dry sauces. Thin milk is used for soups and general cooking. This distinction is usually not made in Western nations since fresh coconut milk is usually not produced, and most consumers buy coconut milk in cans.
Manufacturers of canned coconut milk typically combine the thin and thick squeezes, with the addition of water as a filler. Depending on the brand and age of the milk itself, a thicker, more paste-like consistency floats to the top of the can, and is sometimes separated and used in recipes that require coconut cream rather than coconut milk. Shaking the can prior to opening will even it out to a cream-like thickness.
Some brands sold in Western countries add thickening agents to prevent the milk from separating inside the can, since the separation tends to be misinterpreted as a sign of spoilage by people who have no experience with coconut milk.