Market Scene : Wine on the Rocks--at 10 Degrees : Canadian vintners make sweet profits by picking grapes in arctic weather for admirers worldwide.

Bundled into down-filled parkas, heavy gloves and waterproof boots, the grape pickers crunch through the snow, moving in and out of triangles of illumination cast by standing arc lights.

They work quickly, snapping bunches of grapes, frozen hard as marbles, from the vines and dropping them into plastic boxes. It is midnight, and the thermometer registers 10 degrees.

The annual winter ritual of the icewine harvest is under way here in one of Canada’s premier wine-growing regions, 6 1/2 miles downriver from Niagara Falls. Now in its 10th vintage, the event has become the wine-country version of a community barn-raising.

Here are Robin Charlwood, a senior executive for an international engineering firm, and son Nick, a recent university graduate, cheerily picking grapes at the Inniskillin Winery, a pioneer in the Canadian icewine business. This is their fifth year in the fields.

It may seem “a little lunatic,” Charlwood concedes with a laugh, but it’s “a great experience.”

And uniquely Canadian. Every year there are more applicants than the winery can accommodate.

The 45 or so others joining this exercise in chilly camaraderie include salesmen, hotel workers, housewives, the maitre d’ at a local resort, an official from the Ontario government agency that markets all liquor in the province, including the dessert wine made from the grapes at Niagara-on-the-Lake. A reporter from CBC radio has arrived and will broadcast from the vineyards the next morning.

The midnight harvest evokes a true sense of community, and the icewine that results has become an important product for Canada’s infant wine industry, centered here in southern Ontario and in the Okanagan Valley of British Columbia.

Since Inniskillin’s vintage 1989 icewine won a breakthrough award at the prestigious Vinexpo in Bordeaux in 1991, Canadian icewine has become a consistent winner of dessert wine competitions from Chicago to Verona, and the only Canadian wine with a significant export market.

“It’s definitely a signature calling card that draws people into our industry,” says Christine Coletta, executive director of the British Columbia Wine Institute in Vancouver. “When we’re overseas at Vinexpo and other competitions and trade shows, it seems like even those with limited English know the word ‘icewine.’ ”

It is particularly popular in Japan, where it sells for as much as $130 a half bottle. In Toronto and other parts of Ontario, where icewine retails at $20 to $35 a half-bottle, sales jumped more than 25% between 1993 and 1994.

Icewine’s high price stems from the steep costs and low grape yield inherent in the process. Grapes are picked at temperatures of 14 degrees Fahrenheit and below, when most of the water in the juice is frozen, then pressed immediately, yielding only a small amount of highly concentrated juice. As the only wine-making country that consistently experiences temperatures needed for icewine (picking icewine grapes with the regular fall harvest and then refrigerating them is considered bad form), Canada has become the world’s largest producer.

No one is going to confuse Canada’s wine-growing areas with Burgundy or the Napa Valley, however. At least not yet. For one thing, production in Ontario and British Columbia combined totals only about 5 million cases a year. That’s somewhat less than California’s Sonoma-based Sebastiani Vineyards alone produced in 1993.

Inniskillin President Donald J.P. Ziraldo says that when he looks at the output of California giants such as E&J; Gallo, “the joke around here is that they spill more than we make.”

What aficionados call the new era in Canadian wine began about two decades ago, when Ziraldo, Inniskillin winemaker Karl Kaiser and a few others set out to make fine wine from such grape varieties as chardonnay, gamay and riesling in Ontario.

Previously, Canadian wine was made from hybrid grapes and was, to quote Toronto wine critic David Lawrason, “horrid.” That left a legacy of consumer skepticism that has only recently been pierced, the critic observed.

“There was a huge, long history of bad wine to overcome. It may take a generation, but they’re working hard at it,” says Lawrason, who writes on wine for the Globe & Mail, Canada’s national newspaper.

He says that while no single Canadian winery as yet succeeds across the board with all its products, some very good Canadian wines are being bottled.

Michael Carlevale, owner of Enoteca della Piazza, a top Toronto wine bar, agrees. “Anyone who loves and respects wine knows each wine is an individual, and should be approached on that basis, because great wines, like great people, can come from unexpected places,” he says.

Canada’s successes with icewine and some other varieties in international competition has helped overcome consumer resistance, Ziraldo says.

“It does humongous things for our sales here in Canada if some Frenchman says our chardonnay or whatever is the best.”

Ziraldo, 46, recently has devoted himself to setting up the Vintners Quality Alliance, which enforces quality control and truth-in-labeling standards similar to those in France and California. Six years after its inception, there are 30 member-producers in Ontario.

Now Ziraldo is eyeing the export market. Inniskillin recently became a subsidiary of Vincor International Inc., a diversified beverage company and one of the top 10 wine producers in North America. Ziraldo, who will continue to operate Inniskillin, says expansion into the U.S. market is likely.

Seated on a picnic table bench in the converted barn that serves as Inniskillin’s on-site retail outlet, Ziraldo is taking a break from supervising the icewine harvest. But soon he’s back in the vineyards, greeting veteran pickers, introducing himself to newcomers, making sure the CBC reporter finds a spot in the office to nab a few hours sleep before her broadcast.

At 4 a.m. it becomes clear that the harvesters are filling boxes faster than the crushers can press the grapes, and Ziraldo decides to knock off an hour early. Colder now but retaining their enthusiasm, the volunteers move out of the fields. Robin Charlwood says he’s seen a shooting star.

Ben Nicks, a former resident of Manhattan Beach, now has hands-on experience with wines he serves at the nearby hotel where he is the maitre d’. First-time pickers Karen and Marc Larouche say they’ll probably be back next year.

Everyone files inside the winery to pick up their night’s pay--$15 an hour plus a bottle of icewine. Then they gingerly maneuver their cars down the ice-slick driveway and are gone. The only sound remaining is the rhythm of the wine presses, still processing the grapes left behind.

South across the vineyards, the ridgeline of the Niagara escarpment is visible in the moonlight. Rising behind it is a fantail of mist from Horseshoe Falls. Dawn is still two hours away.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Annual Wine Production

(All types, fiscal year ending 1993)

British Columbia: 1.7 million cases

Ontario: 3.3 million cases.

California: 171.8 million cases

SOURCES: Vintners Quality Alliance, Ontario; British Columbia Wine Institute; Wines and Vines Magazine, San Rafael; Kirby Moulton, economist in Department of Agriculture and Resources, UC Berkeley