Napa, Calif.—CalFire declared the North Coast wildfires contained in late October, leaving wine grape growers in Napa County and elsewhere to take account of how the blazes affected their vines and properties.

Although few vineyards burned during the fires, growers had to deal with debris cleanup, repairing damaged infrastructure such as melted irrigation lines and preparing for winter rains.

A crowd of more than 100 people attended a recent Napa Valley Vineyard Technical Group session that focused on wildfire recovery and included presentations by a series of experts.

Andrew McElrone, a plant physiologist with the United States Department of Agriculture at the University of California, Davis, said growers can look for internal damage by making a small cut in the trunk of a vine similar to the type of cut for T-budding and inspecting the interior tissue. Healthy tissue is moist and creamy white in appearance, while dead tissue would be brown and dry.

Land-use consultant Phil Blake, who previously worked for more than 30 years with the USDA National Resource Conservation Service, said growers should reinforce gullies and ephemeral streams with straw bale dikes, weirs and fiber rolls to slow down runoff and capture sediment and ash.

He said one should expect at least double the amount of storm runoff, and in heavy storms it could be two to three times what’s normal. Farm ponds may need to be protected from runoff by temporary diversion ditches.

Bill Birmingham with the Napa County Resources Conservation District said stream crossings are the most vulnerable parts of roads, as plastic culverts may have melted and concrete and metal culverts could have shifted and will no longer carry stream water beneath the road. He suggested installing a post in front of culverts to keep brush and other material carried by storm water from plugging the culvert and eroding the ground around the road.

Cleaning up wine
Meanwhile, operators of flash détente machines reported a high level of demand for their services following the massive California wildfires. The flash détente process entails rapid heating of must, which blows off a small amount of steam that contains long-chain compounds such as pyrazines or smoke compounds.

Rudy Zuidema, owner of Flash Wine Technologies in Kenwood, Calif., said his Della Toffola flash machine was located in an evacuation zone, so he couldn’t book anyone for service during the height of the fires. Once Zuidema was able to access his facility, he treated nearly 500 tons of grapes. As large portions of Sonoma and Napa counties were inaccessible during the fire fight, vineyards went unpicked and grapes sat in smoke. “We saw quite a bit of business after the fires because the smoke taint is so substantial,” he said.

Nate Rippey, general manager and vice president of production at Carneros Vintners in Sonoma County, said while there was considerable interest in using their services for smoke treatment, the company actually processed fewer tons than it had contracted for because of the fires. “We did see an increase in flash business this year for smoke taint-related issues, roughly by 1,000 tons. That said, we also lost business due to clients rejecting fruit or being unable to harvest.”