A raisin is a dried grape. Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking, and brewing.Raisins are a type of grape that has been dried for around three weeks. Grapes darken as they dry, which gives raisins their dark brown color. A range of grape varieties is used to make raisins. The size, taste and color depend on the type of grape used.