As we count down to Harvest 2026, Elizabeth Spencer Viticulturist Amelie Desmarchelier walks us through how her team measures Brix in the Boisset Collection Sauvignon Blanc vineyard in Rutherford.

At this stage of the growing season, Brix is monitored regularly to track sugar levels and determine when the grapes have reached optimal ripeness. After sampling individual grapes, Amelie used a refractometer to record a reading of 18 Brix.

Once the fruit reaches around 20 Brix, the team begins sampling full clusters and conducting lab testing. When the grapes reach approximately 21 to 24 Brix, they’re nearly ready to harvest.

Follow along as we take you behind the scenes of #Harvest2026 and one of the most exciting times of the year in Napa Valley.