Hand-Picked vs Machine-Harvested Grapes
Texas, California, France, and other wine regions in the Northern Hemisphere are picking grapes Which is better…hand-picked grapes vs. those grapes harvested by a machine? Those who pick their grapes by hand proclaim they expend the effort so as not to damage the grapes. They claim their grapes are a better quality as a result. Is that really true? During the de-stemming and crushing of the grapes, those grapes are broken or pulled off the grape stems with a mechanical device and then crushed to break open the grapes for the juice and pulp and, with red wines, to keep the skins in the fermentation process. In making white wines, the free-flowing juice is placed in a vat while the skins, pulp and seeds are placed in a press to further extract the juice in the pulp and skins. In order to do this, a force is applied to the skins and pulp to extract available grape juice. From my perspective, the grapes are jostled equally whether hand-picked or machine-harvested.
However there are major advantages to harvesting by machine. The grapes are accumulated faster in the vineyards vs the picking of grapes by a large crew. One grape harvester can do the work of more than 100 grape pickers! One person operating a machine vs having a crew of more than a hundred is a huge difference. Normally grape-picking crews are in the range of 15 to 30. As a result, the grapes are delivered to the winery crush-pad faster. As soon as the grape bunch is torn or cut from the vine, biological activity on removed grapes begins. The biological activity can easily accelerate in a time of two to three hours. It is important to get those grapes as soon as possible to the winery crush pad to begin the wine-making process. Rogue yeast and bacteria fermentations can begin and sustain growth in a matter of a few hours. While working as a “cellar rat” at Alexander Valley Vineyards, I notice a huge difference in the temperature of incoming grapes. Those grapes that were machine-harvested were two to three degrees warmer than ambient air temperature vs those hand-picked grapes being around ten degrees warmer than ambient air temperature. The temperature differences were consistent during that crush of 2007. The warmer temperatures meant that rogue fermentations were happening with the winemaker being at a loss of what micro-critters were doing the fermentation. You should also understand that most wineries in North America dose the incoming grapes at the time of crush with potassium meta-bi-sulfites to kill all microbes, wait a day for the potassium meta-bi-sulfites to dissipate, and then inoculate with a commercial strain of yeast that the winemaker has selected for the fermentation to bring out in the fermenting wines what the winemaker wants to accent. Rogue fermentations sometimes impart unusual tastes and off bouquets to fermenting wines.
Another reason for machine harvesting is the need to rapidly pick grapes due to weather or grapes maturing and then losing their acids which are necessary for a wine with depth. It is almost impossible to round up a grape-picking crew due to others also needing that limited labor force and immigration laws which can also limit workers. Cost is also a major factor with machine-harvest costs way less than hand-picked grape costs.
Incoming grapes are also rated as to MOG which is Materials Other than Grapes. Hand-harvested grapes in my experiences have more MOG such as leaves along with rocks from those picking crews that are paid by the pound of grapes.
However, machine-harvesting the grape crop is not possible when there are steep slopes in the vineyards. Those machines cannot adopt to the slopes. In addition, end post configurations support the wires for the trellis system can cause the harvesting machines to skip the first two or three vines. Therefore, hand-harvesting is a necessity to bridge these machine gaps.
As for me, I prefer machine-harvested grapes to make wines because it is less expensive and minimizes rogue fermentations in harvested grapes! Those areas that have hand-picked grapes provide wines that are more expensive with the same quality as machine-harvested grapes. The vineyard managers also do not have the hassle of rounding up grape-picking crews