The Sultana Grapes that are going to be eaten fresh as grapes are harvested first; the ones that will be made into Sultanas are left on the vine a few weeks longer to become overripe and more sugary. The Sultana Grapes are green when harvested for processing into Sultanas. They are dipped in a mix of olive oil and potassium carbonate to be cleaned and to help them develop the golden brown colour as they dry. Larger commercial producers will treat them with sulphur dioxide to improve the colour and speed up the drying process.
Sultana is a good grape to be used for making a dried fruit from as it has a very high sugar content (about 20%), which helps to preserve it, and it is seedless.
The United States is largest producer in world, thanks to California; Turkey is the second largest. Australia is also a big producer in Victoria and South Australia along the Murray River.
While we think of Sultanas as an ingredient for desserts, in the Middle East they are used in many savoury dishes. When you want to sneak a special zing in any recipe you are making, soak them in a booze or juice for about 20 minutes to plump them up with the flavour.
1 cup = 6 oz = 175g
The Sultana Grape may have originated in Anatolia, which is now part of Turkey, but credit for the process of drying grapes into raisins is given to the Persians, as far back as the 1st century BC.