grape juice

Did you ever wonder why grape juice tastes the way it does? Grapes that we buy in the store NEVER taste as sweet as that juice does. I always kind of wondered if it was just kind of a synthetic grape flavor, until yesterday. Mom and dad gave Jay and I some grapes that they got from my aunt and uncle who just came back from Kelowna. These concord grapes....they taste exactly like welches grape juice. I was absolutely amazed! Soooo good! If they grow grapes that tasty in BC, why do the ones we buy at the grocery store come all the way from Mexico and aren't even a fraction as good as these?? *sigh*