A raisin is a dried grape

A raisin is a grape that has been dried, either in the sun or in a controlled environment. The drying process removes most of the water from the grape, concentrating the sugars and creating a wrinkled, chewy fruit that lasts for months without refrigeration. Most raisins come from wine grapes—varieties bred for sweetness and acidity rather than fresh eating—though some are made from table grapes too.

The word "raisin" comes from Old French and Latin roots meaning "grape," though in modern English it specifically refers to the dried form. Fresh grapes and raisins are the same fruit at different stages; the transformation is purely physical, with no added ingredients in most cases.

Key Takeaways

  • Raisins are grapes that have been dried to remove water and concentrate natural sugars, making them shelf-stable for long periods.
  • California produces about 99 percent of the raisins grown in the United States, with most coming from the San Joaquin Valley.
  • The two main drying methods are sun-drying on the ground between vineyard rows and mechanical drying in controlled environments.
  • Raisins contain fiber, potassium, and antioxidants, and are used in cereals, baked goods, trail mix, and as a standalone snack.

How raisins are made

The most common method in the United States is sun-drying. Farmers cut grape bunches from the vine and lay them on the ground between the rows to dry in the sun for two to three weeks. During this time, the grapes lose about 75 percent of their water weight. Once dry enough, a machine sweeps the raisins into a windrow, and another machine picks them up and transports them to a processing facility.

A smaller portion of raisins are made using mechanical drying, where grapes are placed in large bins or tunnels and dried with heated air over several days. This method takes less time and uses less land, but costs more to operate. Some producers use a drying agent—a solution sprayed on the grapes before sun-drying to speed up the process—though this is less common in the United States.

After drying, raisins go to a processing plant where they are cleaned, sorted by size and quality, and sometimes treated to prevent clumping. Most raisins sold in stores contain a small amount of vegetable oil or gum arabic to keep them from sticking together in the box.

Where raisins come from

California grows nearly all raisins sold in the United States. The San Joaquin Valley, in the state's central region, has the climate and soil that suit raisin production: hot, dry summers and mild winters. The valley produces roughly 350,000 tons of raisins per year, making it the world's largest raisin-producing region.

Turkey is the second-largest producer globally, followed by Iran, Greece, and China. Each region's raisins have slightly different flavor profiles depending on the grape variety and drying method used. Turkish raisins tend to be larger and darker; Greek raisins are often smaller and tangier.

Types of raisins

The most common type in the United States is the Thompson Seedless raisin, made from Thompson Seedless grapes. These are small, dark, and sweet, and make up the majority of California's crop. They are the raisins you find in breakfast cereals and standard snack boxes.

Flame Seedless raisins are larger, redder, and slightly less sweet than Thompson Seedless. Muscat raisins are made from Muscat grapes and have a stronger, more complex flavor; they are larger and chewier. Sultanas (also called golden raisins) are dried using a mechanical process and treated with vegetable oil to keep them lighter in color and softer in texture. These are less common in the United States but widely available in specialty stores.

Nutritional content and uses

A quarter-cup serving of raisins contains about 100 calories, 24 grams of carbohydrates (mostly natural sugars), 1.5 grams of fiber, and small amounts of potassium and iron. Raisins also contain polyphenols, compounds with antioxidant properties. Because they are high in natural sugars and low in water, they are energy-dense and can cause tooth decay if eaten frequently without rinsing your mouth afterward.

Raisins are used in a wide range of foods: breakfast cereals, granola, trail mix, baked goods like cookies and bread, oatmeal, and savory dishes like curries and rice pilafs. They are eaten plain as a snack and are sometimes soaked in water or alcohol to soften them before cooking. In some cultures, raisins are a traditional ingredient in meat stews and grain dishes.

Storage and shelf life

Raisins last for several months to over a year when stored in a cool, dry place in an airtight container. They do not need refrigeration. If raisins dry out further and become hard, you can soften them by soaking them in warm water for 10 to 15 minutes. If they develop mold or smell fermented, they should be discarded.

Raisins can be frozen to extend their shelf life, though freezing may change their texture slightly. Many people store opened boxes of raisins in the refrigerator or freezer to keep them fresh longer, especially in warm or humid climates.

Frequently Asked Questions

Are raisins and currants the same thing?

No. Currants are dried berries from a different plant (Ribes species), not grapes. They are smaller and tangier than raisins. The term "currant" is sometimes used loosely in the United States to refer to small dark raisins, but true currants are a distinct product.

Why do raisins have wrinkles?

The wrinkles form as the grape loses water during drying. The skin shrinks faster than the interior, creating folds and creases. This is a natural part of the drying process and does not affect the quality or taste of the raisin.

Can you eat raisin seeds?

Most raisins sold today are seedless, meaning they come from seedless grape varieties. If you encounter a raisin with a seed, it is safe to eat—the seed is straightforward a small hard pit. You can swallow it or spit it out.

Do raisins go bad?

Raisins have a long shelf life and do not spoil easily. They can harden if exposed to air for a long time, but hardened raisins are still safe to eat. Discard them only if you see mold, smell fermentation, or notice an off odor.