FOX31 Denver

2 years of October freezes put a chill on grape harvest

PALISADE, Colo. (KDVR) — Many grape vines have small clusters of tiny purple grapes dying at the Grande River Vineyards in Palisade.  A worker tending to the vines explained, “They are damaged.” 

“The cold wiped out everything,” head winemaker Rainer Thoma said. “The vines were still active. So, water froze and erupted the vines.”

Thoma said grapes were ruined by frigid cold temperatures last October with two nights of extreme cold as well as a Halloween freeze in 2019 which also damaged vineyards across the Grand Valley. 

Grower Kaibab Sauvage, owner of Sauvage Spectrum, estimates crop losses in some grape varieties at 90% of the vineyard.

“They were hardy down to 20 degrees and we hit 14 degrees,” said Savage. “Last October we had a sudden plunge in temperature which caused the trunks to split.”

According to Thoma and Sauvage, the damaged grapes were primarily Vitis vinifera grapes, which are native to Europe and the Mediterranean region.

Sauvage said late maturing varietals like Merlot and Petit Verdot suffered damage but Cabernet Sauvignon fared the worst. 

How Colorado’s altitude impacts wine growing

At 4,728 feet Sauvage grows 26 varietals across 60 acres, plus he manages 15 acres of fruit trees.

Sauvage told the Problem Solvers that the altitude and weather have played a role in early harvests two years in a row. Growers told FOX31 both a limited number of grapes to harvest thanks to the cold and an extremely hot growing season have led to the early harvests. 

Sauvage said they are nearly finished with this year’s crop and that a normal harvest stretches through October. 

Early harvests though are not all bad according to these wine makers. 

“Early maturation of the fruit can be a very good thing especially on very late season varieties like Mourvèdre that some time struggle to reach full maturity before the end of the season,” said Sauvage. 

Growers considering crop changes

Because of Colorado’s altitude and short growing season, both growers are turning to American hybrid vines which they believe fair better in the region’s climate. 

They are working with Horst Caspari, a viticulturist with the Colorado State University Western Colorado Research Center who is blending grapes in a selective breeding process called cultivars.  

“As a result, there is very limited amount of fruit of those cultivars available this year,” said Caspari. “In many vineyards, vines of those cultivars need to be retrained from the ground up and do not have any fruit at all this year.”  That means wine growers are starting over by pulling out and replacing damaged vines. 

Caspari, who has studied how to grow Grand Valley grapes and turn them into wine for 21 years, said he believes approximately 20% of Colorado’s vineyards are now planted with varieties that can better withstand the cold due to their reliability.

“We have grown some of those cold hardy cultivars in research plots for 20 years and have never lost the crop. Not from cold events in November 2006, December 2009, January 2013, December 2013, October 2019 and October 2020,” said Caspari, who also owns a vineyard. 

The Western Colorado Research Center has researched wine making since the 1970s. 

“I think in the context of cold damage, our most important research has been the evaluations of cultivars that are better suited to our climatic conditions,” said the grower, who was educated and trained in Germany. 

These wine makers believe the main disadvantage to growing different cold weather varieties is the lack of name recognition. That breeds fear that customers will worry about what they taste like.

“Everyone knows Chardonnay and Merlot, but few know for example Chambourcin and Traminette,” said Caspari.

Caspari said this is a hurdle that wineries will overcome as more of their blends win awards and name recognition. 

Success stories for Colorado’s wine makers

“We recently won two international awards” said Sauvage. “We are still picking these. What do they want to be maybe a Petite Pearl and mixed with Verona? We are figuring out how to put this together which is the art of wine making.”

Caspari believes the region’s transition to cold weather varieties is paying off. 

“That work is ongoing, and we continue to discover cultivars that do well even in extreme cold events like the ones in October 2019 and 2020,” said Caspari “I have a 100% crop loss on my European cultivars, but a full crop on the others. In fact, we will pick the biggest crop ever on one of those.” 

USDA recently designated Mesa and Delta counties as natural disaster areas for wine makers who suffered crop damaged.