Tom S, et al.,
You might be right Tom,
My sampling procedure was this: Pick a berry from random vines across
the plot (about 15 total), crush them all in a sandwich bag, take a
reading with a refractometer.

The grapes taste fine to me. Not too sweet nor too tart.

So I guess I need to pick a bunch of clusters from say 10-12 vines,
crush and let soak overnight and then take a reading?

I'll check on the color of the seeds and stems as well.

Thanks for all the input.

Joe