Jamie Slingerland spends a lot of time checking the weather.
As director of viticulture for Pillitteri Estates Winery in Niagara-on-the-Lake, Ontario, he needs the temperature at 17–18°F to harvest grapes for ice wine. Slingerland used to pick grapes in late December, but he says warming temperatures have shifted harvest times and fewer frigid nights have made the crop less predictable.
“In the years since I started harvesting ice wine grapes, the windows of cold temperatures have become less and we’ve had fewer and fewer opportunities to harvest,” says Slingerland. “We used to pick two or three times between Christmas and the New Year. Now, that happens once every five to seven years.”
Canada is the largest producer of ice wine in the world. The crop generates more than $6.8 billion annually, but climate change could thaw the thriving industry.
“Europe used to be a competitor of ours in the ice wine industry, but they’ve had extremely warm winters these last five or six years and there has been no real ice wine crop… I worry that we will have a similar situation here.” –Jamie Slingerland, director of viticulture, Pillitteri Estates Winery
To make ice wine, grape varieties like Vidal Blanc, Riesling, Cabernet Franc and Cabernet Sauvignon are left to freeze on the vine, ideally thawing and refreezing multiple times throughout the season. The grapes are harvested while frozen, which ensures water in the fruit has separated from the sugars. Once pressed, the resulting juice is concentrated and sticky sweet, ideal for producing Icewine.
Data shows a steady decrease in the number of days where it’s been cold enough to harvest grapes for ice wine. In January 1977, there were 26 days below 18°F. By January 2007, the number of suitable days fell to just three.
To complicate matters, warming temperatures make vines more sensitive to cold, prone to freeze damage and reduce their ability to survive extreme cold. That’s caused significant reductions in yield, according to one study.
Growers are worried about the impact of climate change on ice wine production, according to Gary Pickering, researcher at the Cool Climate Oenology and Viticulture Institute at Brock University.
“I think the big concern is what lies ahead,” says Pickering.
The Race to Adapt Heats Up
Although Pillitteri Estates Winery has never missed a harvest, Slingerland admits that it’s become more difficult to gather the 50 acres of ice wine grapes needed during an ever-shrinking window of cold temperatures.
In 2002, temperatures dropped below 18°F on just two nights. A crew of 65 raced to get the grapes off the vines. Slingerland decided manual harvesting was no longer sustainable. The vineyard started to adopt mechanical harvesters. It allows the team to harvest the full crop, as regulations require picking to cease when temperatures warm up.
“Climate change has definitely impacted our grape growing and wine industry here and our ability to produce ice wine, but we, the growers, the wineries, have adapted to that change,” he says.
Mechanical harvesting is just one of the ways that growers have adjusted to a changing climate. In Ontario, vineyards are being planted further north, which has created new wine regions in areas like Prince Edward County and Georgian Bay.
“I have to ever put a positive spin on climate change,” says Pickering. “But we can migrate north. We have a lot of land up there, and we have to realize that we might fare better than most because of our geography.”
Growers also now plant varieties once considered unsuitable to the Niagara region. Pickering cites climate change as the main reason growers are devoting increased acreage to Italian red grape varieties, like Sangiovese and Nebbiolo.
“What we’re seeing in Niagara already, and what we predict to see much more of, is much greater success with warmer and even hotter-climate varieties…because we know we’ll get warmer temperatures during the ripening season and see less extreme cold events during winter,” says Pickering.
This most recent season, the first 18°F night the Niagara wine region on November 22. Grapes harvested too soon are less sweet and produce less complex ice wines than those that remain on the vines through several freeze/thaw cycles.
“I don’t have enough [Icewine] to get us through another year, so we’d have to harvest next year, but with the weather, we never know what we’re going to get.” –Fraser Mowat, owner, Harbour Estates Winery
Based on the condition of the grapes in the fall, Fraser Mowat, owner of Harbour Estates Winery, decided not to produce ice wine this season. It’s the first year that the Niagara winery hasn’t produced an Icewine vintage since 1999.
“We had enough inventory to carry us through the year,” says Mowat. “I don’t have enough [ice wine] to get us through another year, so we’d have to harvest next year, but with the weather, we never know what we’re going to get.”
Slingerland, concerned that the weather might force him to miss a harvest, has started to build an inventory of ice wine. Pillitteri Estates Winery produced 300,000 liters of ice wine last season, and it plans to continue the practice to protect against weather-related losses. But Slingerland admits it’s not a guarantee.
“Europe used to be a competitor of ours in the ice wine industry, but they’ve had extremely warm winters these last five or six years and there has been no real ice wine crop in Europe,” he says. “I worry that we will have a similar situation here. We have enough inventory to carry us through the next ice wine harvest, [but] could we withstand two years in a row? It’d be extremely, extremely hard for us.”
A Chilly Response to Climate Concerns
If temperatures continue to rise over the coming decades, Pickering believes the viability of ice wine production in the Niagara region could be jeopardized.
New research claims that 60% of Canadian wine growers believe climate change has an impact on their vineyards. Some have implemented changes to adapt, but others remain skeptical.
Mowat isn’t willing to blame climate change for skipping the grape harvest this year. Instead, he calls the earlier-than-usual freeze “an anomaly,” something that can happen with any agricultural product.
“[N]o matter what’s happening climate-wise, we are always, as farmers…at the mercy of the weather,” he says.
“[Icewine] does come with risks, there’s no question about it, and that’s why it’s such a unique product. And it’s a product Canadians do so well.” –Bruce Nicholson, winemaker, Inniskillin
In Niagara-on-the-Lake, Ontario, Inniskillin winemaker Bruce Nicholson has produced ice wine for three decades. While he admits that hitting 18°F in late November 2018 made him a little nervous, he remains optimistic.
“In all of the conversations I’ve ever had about ice wine, [climate change] has never come up,” he says. “ I’ve lived here long enough…and we’re not going to get through December, January and February without having that opportunity to pick…so I don’t lose one minute of sleep thinking, ‘Is climate change going to keep us from doing ice wine next year or the year after that?’ ”
Producing a product dependent on a precise temperature is risky business, Nicholson admits, but that is part of the appeal of ice wine.
“It does come with risks, there’s no question about it, and that’s why it’s such a unique product,” he says. “And it’s a product Canadians do so well.”
Last Updated: May 5, 2023
