Raisins are dried grapes. They are produced in many regions of the world, such as Armenia, the United States, Australia, Chile, Argentina, Macedonia, Mexico, Greece, Syria, Turkey, India, Iran, Pakistan, Iraq, China, Afghanistan, Togo, and Jamaica, as well as South Africa and Southern and Eastern Europe. Raisins may be eaten raw or used in cooking and baking.
Raisin varieties depend on the type of grape used. Seedless varieties include the Sultana (also known as "Thompson Seedless" in the USA) and Flame. 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, mini raisins that are much darker in color and have a tart, tangy flavour. 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. Raisins have a variety of colors (green, black, blue, purple, yellow) and sizes.
In the United Kingdom, Ireland, Australia and New Zealand, the word raisin is reserved for the dried large dark grape, with sultana being a dried large white grape, and currant being a dried small Black Corinth grape.
Raisins range from about 67% to 72% sugars by weight, most of which is fructose. Raisins are also high in certain antioxidants, and are comparable to prunes and apricots in this regard. As with all dried fruits, raisins have a very low vitamin C content.
The natural sugar in grapes crystallizes during the drying process.
Raisins are sweet due to their high concentration of sugars. If they are stored for a long period, the sugar inside the fruit crystallizes. This makes the dry raisins gritty, but does not affect their usability. The sugar grains dissolve when the raisins are swelled in (hot) water.