Winemakers are a nervous lot and once you get to know one or two, you wonder if they ever get a restful night’s sleep.
There’s always something to worry about, from late-spring frosts to a wet summer and the accompanying bugs, mildew and birds all the way to picking crews that forget to show up and a market that leaves you overwhelmed with fruit and no place to sell it.
And if that isn’t enough, Colorado each year faces the threat of an early arriving frost that leaves you scrambling to deal with vines loaded with grapes.
Whew. It’s almost like farming.
Temperatures in the Grand Valley and North Fork Valley dropped below freezing several times in the last two weeks, setting records and leaving grape growers scrambling to get grapes off the vine.
An hour or so in the 27- to 28-degree range isn’t enough to ruin the crop, but kills the leaves. When photosynthesis shuts down, grapes stop ripening and producing sugars.
“Basically, when the leaves frost, you only get what the grapes already have produced,” said Cory Norsworthy, winemaker at Grande River Vineyards.
He said the real cold missed most of his grapes.
“We’re sort of in a banana belt here, it only went down to 31 or 32,” he said. “It did shut down some leaves on Orchard Mesa but down here the leaves still look pretty healthy.”
Grapes get sweeter as they lose moisture (called “raisining” because that’s what they look like) while the brix (sugar to water ratio) goes up. This is why late-harvest wines and ice wines are so sweet.
Dead leaves are troublesome (the pieces gets into the crush, making the juice vegetal and green tasting) so pickers want to get the grapes off the vines as soon as possible.
A few degrees makes a huge difference. Twenty-seven degrees will kill the leaves but generally leaves grapes undamaged.
“It didn’t hurt the grapes per se,” said fruit grower Bruce Talbott, “but (losing the leaves means) we won’t be able to build more sugar and mellow more acids.”
At 23, as it was Oct. 13, 2008, grape clusters freeze and get brittle.
“You have four or five days to pick them and (after that), if you bump a cluster, all the grapes fall on the ground,” said Talbott, who farms 120 acres of grapes.
Grape damage was so extensive last year “we were concerned we wouldn’t have enough fruit on the vines,” Talbott said.
The damage this year also was less because some growers already were picking grapes when the cold weather hit.
“By Winefest last year I hadn’t picked almost anything, but this year I had five wines in the tank before Winefest,” said Nancy Janes of Whitewater Hill Vineyards. “Even though the frost came earlier, things were getting riper earlier this year.
“Last year, we processed 110 tons of fruit in three weeks,” she said.
Talbott said frost damage this year was uneven.
“It was really spotty and bizarre the way it happened,” he said. “Some of the areas we expected damage like down along 32 Road were fine and areas we didn’t expect to see damage are hurting.”
Most winemakers report little trouble with harvest, which is expected to wind up in the next week or so.
“I’m real pleased with the fruit I’m getting in,” said Parker Carlson. “As far I know the cold shut down some of the vines but I haven’t seen any adverse effects on things.”
Frost damage in the North Fork Valley apparently was limited to lower vineyards.
“I got some frost but not as much as the people along (Highway) 92,” said Yvon Gros of Leroux Creek Vineyards. “I’m about 1,000 feet higher and it was about 28, 27 here but some places it went down to 24 or 25.”
Gros said his hybrid grapes, including chambourcin and cayuga, seem to resist frost better because their leaves are thicker than other varieties of grapes.
“It was only for a few hours in the morning and that’s not bad. Some of my chardonnay got frosted so it’s not quite where I wanted it but it will be fine,” Gros said.
For some winemakers, cold temperatures offer a mixed blessing. It impacts the normal harvest schedule but late-harvest grapes make for great dessert-style wines.
The Whitewater Hill 2008 Zero Below late-harvest chardonnay won a gold medal at the 2009 Colorado Mountain Winefest.
“We let them hang for 10 days after frost and the brix get real high,” Janes said. “That extra month and a half changes the flavor profile quite a bit.”