The place where I purchase grapes (Corrado's Market in NJ) always has
boxes of grapes they call "mixed black." Has anyone ever tried these?
They never say what kind of grapes they are. Is this the stuff they
can't sell any other way, or does someone attempt to make a blend of
grapes that's better balanced than the individual varieties?

I will be buying grapes this weekend, and I'm wondering if anyone has
tried them or knows anything about them.