Harvest Technology Comes of Age
by Thomas Ulrich
With several inches of rain predicted along California’s North Coast, Moises Frias raced to gather what was left of the 2011 harvest. From the air-conditioned cabin of an over-the-row tractor, he eased up on the throttle, nudged the steering wheel to the left, swung the mechanical harvester onto a tractor path and emptied three tons of Chardonnay into a gondola bound for Cuvaison Estate Wines in Napa, Calif.
During the most recent growing season, vineyard managers faced a cold, wet spring that produced infertile flowers, shot berries and a shorter than average veraison that required many of them to drop loads of immature fruit.
“Lower than expected yields and unpredictable weather combined to make the mechanical harvester and optical sorter an important part of this year’s harvest,” said Steven Rogstad, winemaker for Cuvaison Estate Wines. “The machines processed grapes more quickly and selected berries more carefully than fruit harvested and sorted by hand.”
With local vineyard managers reporting yields of 75% for Chardonnay and 55% for Pinot Noir, a colder than normal summer and the threat of rain, field crews hustled to harvest balanced fruit.
“The beauty of this ranch is that it is divided into discrete blocks for picking,” Rogstad said of the 400-acre Carneros vineyard. “The change in elevation and the small size of the vineyard blocks give us a variation in ripeness.”
But lower than average yields and uneven ripeness made it a challenge to harvest fruit that was both flavorful and ripe.
“A block of Pinot Noir that normally produces 4 tons,” Rogstad said, “yielded three-quarters of a ton this year.”
And according to some vineyard managers, the early October rainstorm lowered sugar levels and created perfect conditions for Botryitis.
With so much at stake, the 2011 harvest provided winemakers and vineyard managers with ideal circumstances to evaluate multi-purpose harvesters, optical sorters and a new gondola that separates the juice from berries before the grapes even reach the winery.
Ahead of the curve
At approximately $300 per ton, mechanically harvesting and sorting grapes makes sense for many vineyard managers and winemakers. Harvesting and sorting premium grapes by hand can be several times more expensive, but it is a complicated decision that demands more than simply calculating the cost of harvesting and sorting grapes.
Early adopters of the new generation of harvesting and sorting equipment have discovered these machines can accelerate production, reduce the number of field and winery workers and preserve varietal character. Annual sales for these sophisticated multi-purpose tractors have doubled in the coastal areas of California, Oregon and Washington since manufacturers introduced on-board sorting in 2008.
Rogstad, like many other vineyard managers and winemakers, believes that quality begins in the vineyard. Without the highest quality grapes, he reasons, he cannot produce a memorable bottle of wine.
During 2009, Rogstad and a handful of other premium U.S. winemakers and vineyard managers challenged the notion that hand-picked always trumps mechanically harvested fruit. He and vineyard manager Rolando Sanchez led a team that hand-picked and machine-harvested alternate rows of grapes from a 5.5-acre block of Carneros Chardonnay.
“I was impressed by the quality of the pick,” Rogstad said.
Lab results confirmed that the Brix, pH and TA were identical at harvest, with the acids running slightly higher in the machine-harvested fruit.
Another Napa Valley winemaker, Jeffrey Stambor of Beaulieu Vineyard, compared machine-harvested and optically sorted grapes to hand-picked and sorted fruit from the same vineyard block during the 2009 vintage. The vineyard team hand-picked or machine-harvested every four rows from a Cabernet Sauvignon block located in Rutherford.
Stambor waited until the winery was ready to release the 2009 Cabernet Sauvignon to evaluate results. “There was not a huge difference between the wines made from machine- and hand-picked fruit,” Stambor said. “The wine made from the machine-harvested fruit contained 15% to 20% more tannin, which in itself is neither good nor bad, but is an indication of what to expect and how we might adjust fermentation techniques given the harvest method.”
Repeated sensory evaluations of the wine by a panel of 20 tasters revealed no clear preference between the 2009 Cabernet Sauvignon made from hand-picked and machine-harvested fruit.
For batches of 2010 Pinot Noir, Rogstad analyzed barrel samples made from hand-picked and machine-harvested fruit. “Both wines were very high quality,” he said. And like the outcome of the sensory evaluation for Beaulieu Vineyard’s 2009 Cabernet Sauvignon, the tasting panel for samples of the 2010 Pinot Noir could not agree which way of harvesting produced better results.
Man or machine?
“In a normal year, we would start picking Chardonnay shortly after Labor Day and harvest it in six weeks,” Rogstad said. “This year, we started harvesting Sept. 23.”
With all of the Pinot Noir picked before the Oct. 3 storm, Rogstad concentrated on harvesting and pressing the Chardonnay. The vineyard team had picked only three-quarters of the 2011 crop, and rain from the upcoming storm would increase the chances of Botrytis dramatically.
Facing some of the same circumstances in 2009, Andy Mitchell, director of vineyard operations for Hahn Family Wines, conducted his first major test with the new-generation harvesting equipment. (See “The Year of the Harvester?” Wines & Vines May 2010 issue.) Today, Mitchell harvests nearly all of Hahn Family Wines’ vineyards with multi-purpose tractors.
“The mechanically harvested grapes are higher in quality than hand-harvested fruit, and vineyard and winery operations are much more efficient—saving us money and improving the quality of the wines we produce,” said Bradley Saunders, vice president of finance and CFO of Hahn Family Wines.
Instead of field workers frantically picking clusters of grapes by hand, the mechanical harvesters whip 4-foot-long fiberglass tension rods back and forth, snapping the robust berries from the vine and leaving the lighter berries, rais ins and a steady blast of air in their wake.
“In a year like this,” Stambor explains, “the harvester shakes the vine ahead of the machine so that Botrytis-infected berries fall from the vine before the harvester picks them.”
Keeping pace with the vineyard
Two mechanical harvesters and a crew of five harvested 100 tons of Cuvaison Chardonnay during the three days leading up to the October 2011 storm—plus another 100 tons in the days that followed.
“The old generation of harvester would harvest sprinkler heads and part of the vine,” said Jeffrey Stambor from Beaulieu. “They’ve dialed in the new generation of harvesters to be much gentler on the vines and the fruit and much more efficient in the vineyard. Add the optical sorter to the mix, and you can bypass traditional destemming and crushing operations at the winery.”
Only a handful of workers operated the Selectiv’ Process Harvester and Vision Optical Sorter at Cuvaison, which together can process more than 40 tons of fruit per day. Rogstad estimates that hand-sorted fruit requires 10 to 20 people for a berry sort and three to four people for a cluster sort. The optical sorter requires four to five people, but throughput is three to six times faster than sorting fruit by hand.
“In a vintage like this, where there was so little time between the onset of harvest and the first major rain event,” Rogstad said, “we would have been sunk without this processing speed.”
Like the mechanical harvesting and sorting equipment, the Gimbre gondola that separated the juice from the berries on its way to Cuvaison Estates makes winemaking more efficient.
Notes from the crush pad
Once the Gimbre gondola reached the winery, the grape juice, which had drained into the gondola’s false bottom, was pumped to a 550-gallon stainless-steel tank, covered in a blanket of CO2, weighed and then pumped to a 5,000-gallon fermentor, cutting the time from harvest to tank by almost half.
“Because phenolics are picked up in the skin,” Rogstad said, “we drain the free-run juice from the skins as quickly as possible. Storing the juice in a stainless-steel tank saturated with CO2 limits oxidation.”
Winery workers poured berries from the gondola’s bib-like shaker table into a Pellenc destemmer that dropped them onto a conveyer belt before delivering them to a Pellenc optical sorter.
For machine-harvested fruit arriving at the winery in a macro-bin, the grapes are dropped into a Bucher Vaslin hopper, which places them on a 9-meter shaker table that separates debris from the grapes. A 4.5-meter conveyor belt lifts the stream of grapes to the destemmer, which removes the remaining stems and petioles.
A vibrating table carries the grapes to a rope conveyor made up of 99 parallel cords that align them for final inspection. The optical sorter photographs the berries and extraneous debris as they move toward ejection jets located at the end of the conveyor. The jets fire as seeds, jacks, raisins and imperfect berries clear the end of the conveyor, hurling them toward the waste bin. Momentum from the rope conveyor carries the unblemished grapes past the threshold onto a bin set aside for collecting the harvest.
Coming of age
“The mechanical harvester and optical sorter combined for better berry selection, especially in a year when we are facing Botrytis,” Rogstad said. “In addition, the machines processed the grapes more quickly.” And as many winemakers and vineyard managers learned during the 2011 harvest, speed and accuracy are vital for a vintage characterized by so much uncertainty.
With an estimated 85% of winegrape growers from large-scale farms picking fruit with mechanical harvesters, it may be time for premium growers to consider harvesting and sorting by machine. More than half of all growers farming fewer than 500 acres—and 92% of vineyards smaller than 49 acres—harvest their grapes by hand.
During the past three years, winemakers and vineyard managers from Beaulieu Vineyard, Clos Pegase, Cuvaison, Estancia, Gundlach Bundschu, Hahn, Paraiso and other wineries have led by example.
“Manufacturers continue to refine their designs to suit the needs of higher end wineries,” said James Wolpert, viticultural extension specialist from the University of California, Davis. “Vineyard managers and winemakers producing the most expensive bottles of wine should stay tuned, because even if they prefer hand-picked and sorted fruit, one day they may not find the labor to harvest and sort it.”
Thomas Ulrich wrote a story about measuring transpiration rates with wireless sensors for the July 2011 issue of Wines & Vines. He teaches journalism at San Jose State University.
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