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10/01/2011

Harvesting Grapes: Two Ways to Tango

The California wine grape harvest is in full swing, with wine grape growers and winemakers up and down the state hustling to bring in their grapes at the perfect point of ripeness. When it comes to picking that luscious fruit off the vine, there are two ways to do it: by hand or by machine. Each method has its advantages, and each grower and winemaker must consider a number of factors when determining which one to use. Some California growers and wineries hand pick all their grapes, others use mechanical harvesters, and some do both.

The oldest and of course most traditional method of harvesting is by hand. Crews of vineyard workers move quickly through the vineyard row by row, vine by vine, using shears or a curved harvest knife to carefully cut off the ripe clusters. Each worker has his/her own small picking bin, sometimes called lugs; when full, the lugs are dumped into larger macro bins on a tractor which follows the crew down the rows.

Mechanical harvesters, on the other hand, work by gently vibrating the vines so that the grapes are separated from their stems, dropping them onto a conveyor belt that brings the fruit to a holding bin. In recent years machine harvesting has become more widespread in wine regions throughout the world, including California. First introduced in the 1960’s, these machines have become ever more sophisticated, with sorters and blowers that get rid of unwanted leaves, stems and what’s called “MOG” (material other than grapes) before the grapes hit the bins.

One of the biggest advantages of mechanical harvesting is speed. A machine harvester can theoretically run 24 hours a day, harvesting 80 to 200 tons of fruit, while an experienced hand picker can only harvest between one to two tons a day. Speed is a big benefit when a grower needs to get fruit off the vine fast, say in a large vineyard where all of the fruit reaches peak ripeness at the same time. A mechanical harvester makes it possible to pick the fruit before any over ripening occurs. Machine picking also often occurs at night when the air is cool, which better preserves the fruit until it reaches the winery. And of course there is a cost benefit to being able to pick the grapes more quickly. “It’s about three times more expensive to hand pick grapes,” says Mike Heringer, proprietor and vineyard manager at Heringer Estates, which farms 150 estate acres and manages 600 additional acres of vines in Clarksburg, California. ”And with labor becoming a scarcer resource in California, growers and wineries have to take that into consideration.”

Still, harvesting by hand has several key advantages. “An experienced crew will essentially sort your fruit in the vineyard, avoiding MOG as well as clusters that aren’t in perfect condition,” says Heringer, who notes that some wineries that hand harvest will sort the grapes again on special sorting tables at the winery, something that’s not possible with machine harvested fruit. “With hand-picked grapes you have more control over what goes into the crusher and what ends up in the tanks and barrels. Avoiding tiny leaf particles, stems and the small percentage of fruit that does not meet the standard might seem like a little difference, but it can add up and make a big difference in the quality of wine you produce.”

Heringer, who makes wine for his family’s winery and also sells fruit to wineries throughout California, also points out that there are some styles of wines that have to be hand-picked. “If a winemaker wants to do whole cluster pressing on a Chardonnay or Pinot Noir, you have to use hand-picked fruit so that the clusters are still intact.” Another factor in deciding whether to machine or hand harvest is how far the grapes must travel to get to the winery. “If I know the fruit is going to be on a truck for several hours before getting to its destination,” says Heringer, “I’ll strongly recommend hand-picking. Machine picked grapes, which are slightly punctured from being torn off the stems, might break down in transit, allowing oxidation, spoilage or even unwanted fermentation to occur.”

Under the right conditions, however, Heringer thinks mechanical harvesting can be the right way to go, especially if the crushing facility is close. If a grower knows his/her fruit will be machine harvested, there are techniques they can use in the vineyard to prepare for it. While many of these techniques are also used with hand harvested fruit, they may be more pronounced when the fruit is to be machine picked in order to deliver comparable high quality wine grapes.

“There are a lot of things we do in the vineyard to ensure the machine picks only the fruit we want,” says Heringer. “We practice deficit irrigation so the vine canopy isn’t so big, we pull 100% of the leaves around the fruiting zone, and we go through the vineyard before harvest, taking out non-conforming or inconsistent fruit so that it doesn’t get picked up by the machine.”

Like most California wine grape growers, Heringer sees advantages to both hand harvesting and mechanical harvesting. Variables such as timing, economics, distance, vineyard age and configuration as well as winemaking style must all be taken into consideration when choosing between the two methods.

“There is no right or wrong,” says Heringer. “It’s just another piece of the puzzle.”

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Both machine and hand harvesting have their advantages.

 

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