Garlic is sold fresh or dried and processed into flakes and powder.
The most common varieties include the white-skinned American garlic, which is strongly flavored, and Mexican and Italian garlic, both of which are milder and have mauve-colored skins. Depending on the variety, individual cloves of American, Mexican, and Italian garlic can range from 1/2 to 1 1/2 inches (1.3-3.8cm) in length.
Green garlic, available occasionally in specialty produce markets, is young garlic before it begins to form cloves. It resembles a baby leek, with a long green top and white bulb, sometimes tinged with pink. The flavor of this baby plant is much gentler than that of mature garlic.
In addition to fresh, garlic is sold as dehydrated garlic flakes (sometimes referred to as instant garlic). These are slices or bits of garlic that must be reconstituted before using, unless you are adding them to a liquid-based dish, such as soup or stew. Ground dehydrated flakes are sold as garlic powder. Garlic salt is garlic powder blended with salt and a moisture-absorbing agent.