Effect of Fruit Cane Severance of Grapevines on Must and Wine Yield and Composition

¹ P. O. Box 420, Napa, California 94558

The practice of severing fruiting canes was investigated as a possible adjunct to mechanical harvest of some small-clustered premium wine grape varieties. Drying studies indicated that some varieties could be harvested as single berries within a week of cane severance, with a crop weight loss of 2.6% to 7.7% depending on variety. Must analysis indicated that canesevered samples usually had a higher Brix, higher total acidity, and lower pH than the controls. Wine analysis indicated higher alcohol, higher total acidity, more color, and more phenolic substances in the severed samples. No raisin aroma or taste was defected in the cane-severed samples. No overwhelming preferences were indicated against the cane-severed samples. In many cases the cane-severed samples were significantly preferred or a strong tendency was shown in favor of them when they were harvested within a week of cane severance. Further investigations should be made to determine the longterm effects of cane severance on crop yield, vine carbohydrates, vigor, and durability.