Raisin varieties depend on the type of grape used, and are made in a variety of sizes and colors including green, black, blue, purple, and yellow. Seedless varieties include the sultana (also known as Thompson Seedless in the USA) and Flame grapes. Raisins are typically sun-dried, but may also be water-dipped, or dehydrated. "Golden raisins" are made from sultanas, treated with sulfur dioxide (SO2), and flame-dried to give them their characteristic color. A particular variety of seedless grape, the Black Corinth, is also sun-dried to produce Zante currants, miniature raisins that are much darker in color and have a tart, tangy flavor. Several varieties of raisins are produced in Asia and, in the West, are only available at ethnic specialty grocers. Green raisins are produced in Iran.
