Winemakers Debate Optical Sorting

Tasting conducted at inaugural Innovation + Quality event in Napa Valley

by Andrew Adams
Attendees compare wines made from grapes that passed through an optical sorting machine with those that didn’t Wednesday at the Innovation + Quality conference held at Charles Krug Winery.
St. Helena, Calif.—An optical sorter could easily be the next de rigueur accessory on the well-financed crush pad of a premium winery, but some winemakers aren’t convinced.

The inaugural Innovation + Quality (IQ) conference held Wednesday at Charles Krug Winery featured a panel discussion by winemakers as well as a comparative tasting of wines made with fruit that had undergone optical sorting versus control wines made from grapes that did not pass through the machines.

Billed as the first “forum for ultra-premium wineries,” the event, which was produced by Wine Business Monthly, drew a crowd of more than 1,000 exhibitors and winemakers. In addition to a tradeshow, the event featured several sessions about viticulture, winemaking and the latest academic research. Wines & Vines and Wine Business Monthly are both part of Wine Communications Group.

Sales representatives with companies that make optical sorters, which cost around $100,000 on average, were showing off the machines in the event’s exhibition area, which was set up beneath a huge tent near the newly renovated Krug tasting room. The magazine’s editorial staff bestowed each of the five optical sorting machines currently on the market with IQ awards.

The tasting and panel discussion, held in Krug’s barrel room, featured Dan Kosta, founder of Kosta Browne Winery; Bob Bertheau, head winemaker at Chateau Ste. Michelle; Doug Fletcher, vice president of winemaking for Terlato Wine Group, and Stacy Vogel, winemaker at Miner Family Winery

Sorting in the North Coast
Kosta, who moderated the session, said his winemaking team has been using an optical sorter for more than a year. He said he knows most in the industry have questions about the technology, but as more winemakers start to use the machines those questions are getting answered.

Vogel said she rented a Pellenc machine from Walsh Vineyard Management to use for the 2014 vintage. While Miner is located in Napa Valley, Vogel said the winery has always purchased wine grapes from the Santa Lucia Highlands AVA in Monterey County to make a Pinot Noir. For her trial, Vogel separated the Pinot and made two wines in as identical a way as possible, with the only exception being that one went through the additional step of optical sorting.

Vogel said the resulting wines actually do not taste that much different. During sorting, the optical machine kicked out mostly raisins, and Vogel said the rejected material filled about one bin out of 20 total. “There actually wasn’t a whole lot that was taken out,” she said.

Later in the session, Vogel said it doesn’t seem as if the machines offer a level of sorting that couldn’t be matched by just putting money toward hiring more staff for the crush pad. “I really don’t see this being that different than people sitting there trying to pick out every jack and raisin,” she said. “I really see them as accomplishing the same thing.”

Thoughts from the Northwest
Bertheau said Key Technology, which makes the Vitisort machine used on the Chateau Ste. Michelle crush pad, was quite helpful in getting the unit to run as effectively as possible.

He said the machine was particularly valuable when a vineyard had been struck by a hailstorm that ravaged grapes on one side of the trellis. The machine accurately spat out all the grapes that had been punctured and dehydrated by hailstones. “It’s a perfect use for hail-damaged fruit,” he said.

But like any piece of equipment, Bertheau said it takes some time to get to know how best to operate it. He said vintage conditions as well as variety and vineyard all need to be taken into account when calibrating a sorter. For example, he said the machine seemed particularly sensitive to Merlot and averaged a 7.38% rejection rate on the variety—far higher than other grapes.

All of the sorting machines on the market are equipped with touch-screen control panels that can be programmed with various parameters for specific varieties or vineyards as well as adjusted on the fly.

Bertheau also stressed that an optical sorter is just another “link in the chain” of a crush pad and not a silver bullet. He said the equipment used to bring the grapes to the winery, destem the berries and send them to the fermentation tank are equally as important as the sorter. He added a good destemmer is still as valuable if not more so than a sorting machine.

Sorting in a good year?
Fletcher also rented a Pellenc machine for the 2014 harvest. He said he wanted to determine if the machine was necessary when there hadn’t been any challenges in the vineyard. He said during the 2010 vintage an optical sorter had been a “God-send” when it handled grapes that suffered severe sunburn. “Do we need to optical sort in a good year? That’s our question,” he said.

During his trial, Fletcher set the machine to be as selective as possible to remove every raisin, jack or other piece of MOG on a lot of Cabernet Sauvignon. The two wines tasted slightly different, and Fletcher said the optically sorted wine tasted a bit fruiter. “The lesson for us is, maybe we won’t stress about stem jacks so much,” he said.

Bertheau said in 2014 about 1,700 tons of grapes went through optical sorting out of a total 9,000 tons. He said the number of optically sorted grapes will be a little lower in 2015 to give the winemaking team more time to get better at using the machine. As winemakers and suppliers get savvier with optical sorting systems, Bertheau is confident the technology is just going to get better and used more widely.

Fletcher didn’t seem convinced an optical sorter would be of use every vintage, but he’s heard a supplier is working on a machine that could sort grapes based on sugar content to provide grapes conforming to a narrow band of ripeness. “If that happens, it could be a real game changer,” he said.

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