May 2010 Issue of Wines & Vines

The Year of the Harvester?

Central Coast vineyard managers use machine harvesters to overcome adverse weather in October 2009

by Thomas Ulrich

  • Rain during harvest in 2009 helped demonstrate the speed and versatility of machine harvesting.
  • Picking grapes by machine instead of by hand can reduce MOG from as much as 10% of the harvest to a negligible amount.
  • Harvesting by machine allows the winemaker to pick a vineyard strategically—accounting for changes in weather and ripeness of the fruit.
  • Machine harvesting can reduce the cost of handpicking grapes by two-thirds.
The low rumble of a hydrostatic transmission sets Victor Sanchez’s reflexes in motion. From the air-conditioned cabin of a multi-purpose tractor, he adjusts the conveyor belt, aligns the tension rods, releases the parking brake and nudges the gear lever into drive. The Pellenc 8590 over-the-row tractor pitches headlong down a column of Hahn Winery Syrah on an October morning.

Sailing above a sea of VSP-trained vines, Sanchez surveys the 40-acre vineyard block in the Santa Lucia Highlands of Monterey County, Calif., that he and dozens of field workers will harvest during the next six-and-a-half hours. Every moment counts. Botrytis has infected Doctor’s Vineyard, and director of vineyard operations Andy Mitchell has assigned three mechanical harvesters and 77 field workers to gather what’s left of the 2009 crop.

Will U.S. vineyard managers and winemakers declare 2009 the year of the mechanical harvester? Premium grapegrowers and vintners who compared machine-harvested to handpicked fruit already have reported promising results.

Miles of aisles
For many Central Coast vineyard managers and winemakers, 2009 was a tale of two vintages: near-perfect conditions before the mid-October storm, followed by four days of stifling humidity.

“It was a dramatic harvest,” says Paul Clifton, winemaker for Hahn Family Wines, who drove 1,700 miles (10 round-trip excursions) between the winery’s Santa Lucia Highlands and Paso Robles vineyards searching for perfectly ripe fruit. Grape varieties, even within the same AVAs, didn’t ripen in order.

“Usually, I find a rhythm,” he says, “but not this year. We picked cooler climate fruit (from the Lone Oak vineyard in Santa Lucia Highlands) before harvesting the warmer Doctor’s Vineyard.”

A gathering storm, the mechanical harvester whips four-foot-long fiberglass tension rods to the right and then left, snapping the robust berries from the vine, leaving lighter berries, raisins and a steady blast of air in its wake. The ripe grapes drop onto conveyor belts that rotate to the rear of the tractor at the same speed the harvester rolls forward. The belts elevate the grapes to a second set of conveyors that carries them to a pair of berry separators and on-board sorting tables, dropping the fruit into the holding tank and the petioles, leaves and other debris over the side of the harvester.

With the tractor’s turning radius set to 30 feet, Sanchez harvests every third row before he reaches the far side of a picking block and returns to an adjacent column for the next pass. He empties the tractor’s hoppers into a strategically placed gondola. Drivers stagger trips to the winery, where they dump the berries into a crusher-destemmer before workers transfer them to fermentation tanks.

Nearby, dozens of field workers race to handpick bunches of Syrah. Knots of three or four laborers empty grapes into half-ton macro-bins that circle the 6.5 acre block behind a vineyard tractor. Gondolas transport clusters of grapes to the winery, where workers scatter them across sorting tables and place them into the crusher-destemmer before pumping the juice to fermentation tanks.

Man or machine?
While heavy equipment producers have manufactured machines to harvest grapes since the early 1960s, growers purchase mechanical harvesters when it costs more to pick a vineyard by hand than by machine. But it’s a complicated decision that requires them to consider more than wages alone: Yield, cost per ton to harvest and process the grapes, and quality of the fruit figure into the equation.

“At first we picked Pinot Noir, Chardonnay, Pinot Gris, Merlot and then Syrah,” Clifton says. “One week after the rain, Botrytis (infected Doctor’s vineyard). The machines allowed us to finish the harvest quickly.”

Three multi-purpose tractors harvested 111 tons of grapes from 33.5 acres, yielding 3.323 tons per acre. Factoring a loss for MOG, the field crew hand-picked 24 tons of fruit from 6.5 acres, yielding 3.326 tons per acre. The seven-man mechanical-harvesting crew picked 4.5 times as much fruit as 77 field workers. At current labor and interest rates, a vineyard manager from a medium-size operation looking to replace hand harvesting and sorting with a state-of-the-art mechanical harvester could recoup the cost of the machine in five years or less.

In addition to a timely harvest, winemakers from California’s Santa Barbara County to Washington state’s Columbia Valley are evaluating whether mechanical harvesters can improve the efficiency of their wineries and maintain quality of the fruit.

Jason Smith, owner and general manager of Paraiso Vineyards, farms 300 acres of Pinot Noir in central California. As part of a field experiment, he harvested 15 tons of fruit with a Pellenc multi-purpose tractor.

“Before we tried the mechanical harvester,” Smith says, “I thought machine harvesting was not an option. The Pinot Noir grape is too delicate.”

A mechanical harvester with its on-board sorting table dropped the Pinot Noir grapes into a 2.5-ton hopper before a driver transferred them into a 6-ton gondola for the trip from the vineyard to the winery.

The berries arrived looking like black pearls, according to winemaker Dave Fleming.

“The fruit is much cleaner. You can keep the pump running. The tanks fill uniformly. And, if the fruit is solid, you can drop the amount of SO2 you add at the crusher-destemmer and start fermenting the next day,” he says.

With Pinot Noir vines bearing 50 clusters per vine and weighing at most a quarter-pound per bunch, the mechanical harvester is more efficient than the field crew. According to Smith, the cost per ton to harvest Pinot Noir grapes by machine is one-third of the price to pick them by hand.

With 95% of Pinnacles Vineyard harvested by machine, Scott Kelley, director of winemaking at Estancia, and Jason Melvin, vineyard manager for Estancia’s operations in Monterey County, have discovered ways to make the Soledad, Calif., winery more efficient.

Melvin compares the amount of debris in fruit picked with various machine harvesters. “The stems, petioles, leaves and canes amounted to approximately 2% for a side-conveying harvester and close to nothing for the Pellenc,” he says.

“The fruit arrives at the winery clean enough to bypass the destemmer, avoiding extra handling and processing time,” Kelley adds. “We are able to dump the half-ton bins of fruit directly into our open-top fermentors.”

For the 2009 vintage, Steve Rogstad, winemaker at Cuvaison Estate Wines, machine harvested and handpicked alternate rows of grapes from a 5.5-acre block of estate grown Chardonnay.

“I was impressed with the quality of the pick,” he says.

Lab results confirm that the Brix, pH and TA were identical at harvest, with the acid slightly higher in the machine-harvested fruit.

“Four months after pressing,” he adds, “the hand-picked fruit had not finished malolactic fermentation, but the chemistry of the juice made from the clusters of fruit and the berries remains essentially identical.”

Field notes
“It’s the first technology that we’ve come up with that is different from the 1970s,” says Jason Smith from Paraiso. “The industry has moved from shaking the vine to picking the fruit to multiple tasks that allow you to use the tractor throughout the year.”

A tractor operator and a mechanic can remove a picking head and attach a sprayer. The operator lowers the platform, the mechanic slides off the picking head and replaces it with a sprayer that he bolts to the tractor and attaches to hydraulic ports. After he raises the platform back into place, the operator adjusts the joystick to select the program that sets the controls for the sprayer.

The mechanical harvesting, spraying and spreading equipment ride alongside the over-the-row tractor. Other seasonal work takes place closer to the earth.

Equipped with a twin three-point hitch, the tractor can haul chiseling, disking, mowing and tilling equipment. (The pre-pruning and hedging attachments mount to the front of the tractor.) It can perform two separate operations across two vineyard rows during the same pass.

“For example, you can place a mower on one side and a disk on the other,” says Andy Mitchell from Hahn. “The three-point hitch tracks the center of the row, and the arms compensate for changes in resistance and elevation.”

Other voices
Pellenc, along with Gregoire, Oxbo and Braud-New Holland, manufacture mechanical harvesters. Each machine provides an impressive array of attributes that range from reliability to versatility. When Pellenc introduced the on-board Selectiv’ process for separating and sorting grapes in 2008, the company made its case for producing premium wines from mechanically harvested grapes.

The Selectiv’ process combines a high-frequency linear grape separator and an on-board sorting table to harvest grapes that, according to researchers at the French Institute of Vine and Wine (IFV), contain 0.18% debris. With 80% of the fruit harvested from the vine as whole berries, the linear separator detaches the rest of the fruit from the stem before the grapes roll onto the on-board sorting table.

Comparing Pellenc’s Selectiv’ process with more conventional harvesters, IFV researcher Christopher Gaviglio reports that both methods of harvesting produce excellent results. Harvesting Syrah with an over-the-row tractor carrying a active sorting table on one side and a disabled sorting table on the other, Gaviglio says that the Selectiv’ process removed “significantly more undesirable elements from the harvest, including a significant amount of petioles.”

While Gaviglio concedes that the chemistry of the wine made from the Selectiv’ process fruit and the more conventionally harvested and sorted grapes was not necessarily identical, a tasting panel reported no perceptible difference in its organoleptic qualities.

“It’s clear that new harvesters pick cleaner fruit and whole berries, reducing juice losses in the field,” says James Wolpert, viticulture extension specialist from the University of California, Davis. “Manufacturers continue to refine their designs to suit the needs of higher end wineries. Vineyard managers and winemakers producing the most expensive bottles of wine should stay tuned, because even if they prefer hand-picked fruit, one day they may not be able to find the labor to harvest it.”

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