Brix basics.

Perhaps the most common criteria in determining when to harvest wine grapes is sugar content.  With that in mind, I performed my first °Brix refractometer reading of the Pinot grigio (PG) grapes this morning.  The specific gravity of the soluble solids in a couple of drops of juice (from a random sampling of the PG block) came in at a reading of 23.4 °Brix. Harvest is just around the vino-corner.
Sugar content, however, is not the only determining factor in when to harvest wine grapes.  Visual indicators include the browning of the stems and seeds, both signs of physiological maturation of the berry.  And flavour: old style winegrowers still use taste as a determining factor of grape maturity.  The PG seeds are, I'd estimate, still 25% green.
California is experiencing a bit of a heatwave, so I am aware that my sampling may have had a slightly higher reading due to dehydration. And that's another reason why a °Brix reading is merely one aid in determining when grapes are ready to be harvested.  Stay tuned.