Recently I bought a carton of Concord grapes. They are a deep blue-black color and smell intensely of grape soda or grape candy. The "grape" flavor in most things is really "Concord" flavor -- they're not much like other grapes. If you squeeze them, the skins pop off. We used to grow these when I was little. They made the most amazing, velvety, jewel-purple grape juice and grape jelly. And grape syrup because usually one of the jelly jars wouldn't set.