These are wonderful American grapes and they have an interesting history. They are the usual grapes used in the jelly for the traditional peanut butter and jelly sandwich, and 'Concord' jelly is universally sold in U.S. supermarkets. 'Concord' grapes are used for grape juice, and their distinctive purple color has led to grape flavored soft drinks and candy being artificially colored purple.
Concord grapes are a cultivar derived from the grape species Vitis labrusca (a.k.a. fox grape) which are used both as table grapes, wine grapes and juice grapes.
The skin of a Concord grape is typically dark blue or purple, and often is covered with a lighter colored "bloom" which can be rubbed off. It is a slip-skin variety, meaning that the skin is easily separated from the fruit. Concord grapes have large seeds and are highly aromatic. They are often used to make grape jelly, grape juice, grape-flavored soft drinks, and candy. The grape is sometimes used to make wine, particularly kosher wine, though it is not generally favored for that purpose due to the strong "foxy" (sometimes described as candied-strawberry/musky) flavor. Traditionally, most commercially produced Concord wines have been finished sweet, but dry versions are possible if adequate fruit ripeness is achieved.