Forced-air delivery tubes positioned at individual clusters were used to heat or cool clusters to target ­temperatures. Wires protruding from berries measured skin ­temperature. By Dr. Julie Tarara and Dr. Sara Spayd In grapes, we know that the relationship between sun exposure and berry temperature is important to berry metabolism, composition, and by extension, wine quality. Previous research tells us that in a number of red wine grape cultivars, shaded fruit tends to have poor color at harvest, lower concentrations of anthocyanins (a class of pigments in the berry skins) and soluble solids or sugars, and higher levels of titratable […]