Probably the method of drying grapes was discovered by accident. It is believed that our ancestors tasted the fruits that were dried in the sun and fell off the branch and after realizing its sweetness, they discovered it. Evidence shows that raisins were first produced two thousand years before Christ by the Egyptians. Raisins are specifically mentioned in ancient writings and it shows that raisins, in addition to being eaten, were used to treat diseases and even pay taxes.
To produce quality raisins, these grapes must have special characteristics; For example, they should ripen quickly and dry easily. In addition, their texture should be soft,Do not stick together during storage, do not have cores and have a pleasant taste. The most important grapes for raisin production are: ruby grape, seedless Thompson, muscat, pistachio and royal grape (Sultani).
Until now, the most common grape for raisin production has been the seedless Thompson grape. They are used to produce more than half of the world’s raisins. Ninety percent of them are brought from California. The Thompson grape was first cultivated in 1872 by William Thompson; He grafted cuttings from an English seedless grape with Muscat grapes and created the first Thompson seedless grape variety. It is said that all Thompson seedless grapes that were later cultivated came from this grafted plant.