Measuring Grape Sugar Levels

Determining when to harvest grape sugar levels provides guidance. To get a good grape sample to test the brix, we collect varietal clusters, such as Viognier, throughout the block. Checking the brix allows us to track the grape maturation process and determine the harvest time.

We use a refractometer to measure brix. It is an instrument used to measure the refractive index of a substance, usually a liquid. To use a refractometer, we place a few drops of liquid on the prism, close the cover, and look through the eyepiece toward a light source. The point where the light and shadow meet on the scale indicates the brix reading.

Each grape variety has a different target brix level that we strive for when determining harvest ready. Curt Dunham, Winemaker and Owner of LDV Winery, explains how we measure the grape sugar (brix) to determine when to harvest. Watch this short video.