There are two types of grapes that are measured by weight. A grape that includes seeds weighs 5.1 grams on average, while one seedless grape typically weighs 5 grams.
Grapes have been enjoyed for thousands of years and are considered a healthy snack. A serving size of 32 grapes equals 110 calories per serving. Studies show that they have phytochemicals such as ellagic acid, which is known to aid in the prevention of cancer.
When buying grapes of all varieties, one should select clusters that are nice and plump, of good color and attached to a green stem. Grapes can be stored in the refrigerator, unwashed, for up to one week.