Definition - What does Harvestability mean?
Harvestability of a grape variety is how easy or how difficult it is to harvest based on certain methods, such as whether it's easy or hard to harvest via canopy shakers or by hand. Depending on the harvestability of a grape, the harvest method must be determined. For example, a grape with a difficult harvestability due to the cluster structure of the vine is better harvested by hand.
Harvestability also determines the time period of when the grapes can be harvested in accordance with their region. Causing little to no damage to the fruit and economical factors are both taken into consideration when deciding the method used to harvest.
WineFrog explains Harvestability
Each variety has its own set of factors which determine its harvestability; formation of grape clusters, type of variety and the time of the season when they can be harvested.
The harvestability of a grape can fall under the categories of easy, medium or hard, with some in-between categories. Depending on the category they fall under, grapes can be harvested by hand or by machine. The final decision will further determine the recommended juicing level (light, medium or heavy).
For instance, Merlot is to be harvested from September to mid-October (This may alter depending on the region/growing season). It has easy harvestability and is recommended for harvesting by hand. If, instead, canopy shaking is the means of harvest, the category of harvestability increases to medium, as some bunches will break apart; Merlot is recommended for light juicing.
Chenin Blanc is harvested early from mid-August to mid-September (This may alter depending on the region/growing season). It has medium harvestability. It is recommended that knives or shears are used for hand harvesting. However, harvest can also be done with a rod-type canopy shaker as it removes less rotted clusters. Medium juicing is also recommended for this variety.