Among the concerns Santa Barbara County residents have raised in opposition to cannabis is the fear that certain organic compounds released by the plant will taint nearby grapes, changing the flavor of the wine produced.
Much of this fear is rooted in a 2012 study completed in Australia that found the organic compounds, or terpenes, released from eucalyptus trees have the potential to taint wine. This same eucalyptol terpene is found in some cannabis strains.
Almost every appeal filed against the cannabis projects that county staff have approved this year mentions the issue. During a recent appeal of a project in Santa Ynez, Mike Testa, who recently planted grapes on a property about 700 feet from the potential cannabis farm, said a winemaker who has agreed to purchase grapes from his vineyard has previously canceled contracts with grape growers near cannabis farms in Oregon.
“When I get winemakers that come down from Sonoma and Napa to tour the Santa Rita Hills, I talk far more about cannabis and what is happening in this county than I do about the damn vineyards that we’re touring,” Testa told the county Planning Commission during the Dec. 11 appeal hearing.
In response to these concerns, the Hacienda Company—which proposed the farm that Testa and others are appealing—funded a study to look at whether cannabis grown on its property would taint the nearby vineyard. The company hired William Vizuete, a professor of environmental sciences and engineering at the University of North Carolina, to complete the study and present the results to the county Planning Commission.
For this study, Vizuete measured the type and rate of emissions of five fully mature cannabis plants that are of the same strains Hacienda plans to grow. Vizuete said he found that two of the strains didn’t release any eucalyptol terpenes, and the other three released very small amounts.
Vizuete took the emission rate he developed and then determined how long it would take for eucalyptol terpenes from Hacienda’s farm to deposit on the nearby vineyard at the same amount as in the Australian study. Based on his modeling, Vizuete said it would take 1,121 days of fully mature plants to reach that same level. This is more than 50 times longer than the 21-day period the plants will be fully mature, based on Hacienda’s growing schedule.
Vizuete said these results are based on a worst-case scenario that doesn’t account for trees and other obstacles where the terpenes could be deposited before reaching the vineyard. He said that terpenes don’t travel as far as gas emissions and that the concentration of eucalyptol that led to wine taint in the Australian study was primarily from the oil on the eucalyptus tree leaves.
“The gas phase exposure to wine taint is not a significant route, and that would require extraordinary amounts of exposure time to achieve any amounts of monoterpenes on the grape tissues themselves,” Vizuete told the Planning Commission.
Following Vizuete’s presentation, commission Chair John Parke commended the work and said the study “is a step forward for all of us, everybody in the planning community.” He told the Sun that after months of people bringing up the terpene issue during meetings, this was the first time an applicant or appellant has presented this kind of detailed information.
But despite the study’s thoroughness, some unanswered questions remain, Parke said. For example, the study focused on eucalyptol, but Parke thinks it’s important to find out if other cannabis terpenes can affect wine grapes. Additionally, while Vizuete conducted the study using the concentration amount from the Australian study as a threshold, Parke said it would be good to know how levels below that threshold affect grapes.
Based on Vizuete’s presentation, Commissioner Dan Blough said during the meeting that he thinks it’s unlikely cannabis is tainting wine grapes. But he believes the county needs to step up and fund its own study to officially resolve this terpene dispute.
Parke told the Sun that he agrees this would be the ideal solution, but he said he isn’t sure it would work. First, the Board of Supervisors would have to direct staff to look into this idea and then authorize the funding before contracting with an organization to complete the study. All of this would take time. Meanwhile, there are numerous applicants for cannabis projects navigating the permitting process.
“I think it’s a good idea, but whether it’s a practical idea given the time constraints, I don’t know. … It might be faster if private parties do it,” Parke said.
The Planning Commission didn’t make a decision on the Hacienda appeals during the meeting; however, most commissioners mentioned they were inclined to approve the project. Parke moved to continue the item until February so the public has a chance to review Vizuete’s study and some changes Hacienda made to its project.
So far, the county Board of Supervisors hasn’t directed staff to look into this kind of study, but that could soon change. Fifth District Supervisor Steve Lavagnino told the Sun that he would like to see the county take on such an effort because without a third party like the county conducting a study, there will always be potential claims of bias.
Lavagnino plans to bring up the idea when the board receives information about the county’s quarterly cannabis revenue at its Jan. 14 meeting. He said he can direct staff to look into what this kind of study would entail and how much it would cost, but to allocate money for a project that’s not already budgeted requires support from four out of five supervisors.
“It’s something I would like to see,” Lavagnino said. “Everybody’s got an opinion, but science is science and facts are facts.”
Reach Staff Writer Zac Ezzone at zezzone@santamariasun.com.
This article appears in Dec 19-26, 2019.
