Evaluation of Machine-vs. Hand-Harvested Chardonnay

Abstract

The economics of mechanical harvesting of wine grapes depend on many factors including vineyard location, value of the crop, availability and cost of hand labor, the efficiency of fruit removal, and transport from the catching frame to the gondola. This report describes general performance and identifies juice loss in mechanically harvested cane pruned Chardonnay in Napa Valley. The crop was harvested using a cane shaker (pivotal striker), trunk shaker (rotary pulsator), and a hand crew. Fruit collected in each replication was weighed, assessed for stem content, crushed, and made into wine. Sample vines within each replication were evaluated for fruit not removed, second crop, and ground loss. Results indicate (1) no significant difference in quantity of fruit delivered to the winery, (2) significantly higher stem content and significantly more unharvested fruit in the hand harvested treatment, (3) no significant difference in ground loss, and (4) significantly higher levels of second crop removed by the mechanical harvesters. Adjusting actual yield taking into account cluster stem content, fruit left on the vine, ground loss, and the second crop harvested by machine and not by hand crews, the mechanical harvesters yielded 5.7% to 8.0% less crop to the winery due to juice loss. The value of the juice lost from the mechanical harvesters was offset by the lower cost of operating the mechanical harvesters. Wines produced from the harvest treatments exhibited minor detectable differences but were all high quality Chardonnay wines.