Grapes are a delectable low-calorie snack or dessert; a cup of grapes contains only about 60 calories. Grapes also add fiber to your diet and are naturally low in sodium. Raisins, or dried grapes, are a good source of iron.

Many people also believe that  wine from grapes has health benefits, mostly in the prevention of cardiovascular disease and cancer. This is based on evidence that the phytonutrient, resveratrol, which is found in grapes, can inhibit tumor growth in animals at three different stages of cancer. It is especially high in red wine and is therefore thought to be a possible explanation for the "French Paradox" - the low incidence of heart disease among French people. Research is ongoing to establish the disease-prevention benefit of resveratrol.

Concentration of resveratol is significantly higher in red wine than in white wine, because the skins are removed earlier during white-wine production, lessening the amount that is extracted. Grape juice is not fermented and is therefore not a significant source of resveratrol.

Look for firm, plump, well-colored clusters of grapes that are securely attached to their green stems. Fully ripe grapes are soft and tender. 

Blue Concord grapes are excellent for table use and for making juice and jelly.

The large, purplish-red catawba variety is used primarily for making juice and wine, but can also be served fresh for eating.