Review of the Impact of Mechanical Harvesting and Optical Berry Sorting on Grape and Wine Composition

Summary Aim: The need for mechanical harvesting is increasing, but there have been few new investigations into the potential impact of new-generation harvesters on fruit quality. It is thus timely to review what we know about the impact of mechanical harvesting and identify the gaps in knowledge that should be addressed. Furthermore, new technologies such as optical berry sorting may have the potential to negate the impact of mechanical harvesting on fruit quality. Key Themes: This review provides a brief history regarding mechanical harvesters and concerns about their use. Research that evaluated the impact of harvest method on wine quality is discussed with an additional focus on the consequences of berry intactness and the influence of transport and temperature. An overview of optical berry sorting technology, as well as of its potential impact on wine quality, is provided Impact and Significance: There is a general perception that mechanically harvested grapes produce wines of lesser quality, but there is little evidence supporting that claim. Research to date indicates that the impact of mechanical harvesting on wine composition and style is less than expected. Although most studies indicate an effect of harvest type on grape and wine composition, the few that evaluated the wines sensorially found minimal impact due to harvest method. It is difficult to determine the influence of optical berry sorting because few studies have investigated this technology. In general, these studies found no large impact on wine composition and style. Only one study investigated the potential synergistic effect of using both mechanical harvesting and optical berry sorting and found that optical sorting may negate the impact of mechanical harvesting on grape composition.