I just saw this post. Why not juice the grapes!
You could use a any juicer, your blender, and strain or:
You can use the old method of putting the grapes in a sterile canning jar with however much sugar you want, adding boiling water
to fill the jar, and cap with a sterile lid and ring.
Presto! You are done, the grape juice just has to rest in a cool dry place for a month or so.
Or, after you make your juice you can try wine making!