A SPECIAL GROWERS’ REPORT OF AG ALERT ® C A L I F O R N I A Trees & Vines ®
A fire in Napa County burns near the University of California’s experimental vineyard in Oakville in 2017. Researchers are seeking solutions to smoke exposure, which can damage crops and wine quality.
Researchers work to solve smoke-exposure puzzle ByKevinHecteman
that’s in there so it stands out more?” Determining threshold levels in different varieties will give a better idea of that, she added. “Weeven think thatwewill havemore thanone threshold level per variety,”Oberholster said, “because if you think of the different styles of pinot noir that’s beingmade—you get your really lighter style, thenyouget yourheavier style, youget your fruit-forwardstyle—all of those styles would havemore or lessmasking capabilities. “Those wines have different phenolics, different aroma compounds,” Oberholster added. “We do think that we’re going to have a range of threshold levels, not just one single level.” Two panels at the Unified Wine & Grape Symposium in Sacramento last month looked into the issue. The sessions featured Oberholster and specialists from Oregon State University and Washington State University along with farmer and insurance representatives. In December, $7.6 million federal grant was awarded for research at UC Davis, as well as Oregon State andWashington State, to aid in the search for risk-assessment and smoke-mitigationmeasures. Growers should learntheart ofwine tastingwithaneye toward learning todetect smoke issues, saidElizabethTomasino, associateprofessor of enologyatOregonState. Shenoted that the2020wildfires across theWest led toaweekslongbacklogof tests, “whichdoesnot help froma picking-decision (perspective).”
Yearsofwildfires impactingWesternwinegrapegrowershave farmers,winemakers and researchers looking for answers to smoke exposure, which damages crops and worsens wine quality. Theymay need to be patient, as answers to the complex issue are likely years away. “Everybody now has to make decisions on very limited amount of data,” said Anita Oberholster, anassociate specialist inenology at theUniversity of CaliforniaCooperative Extension inDavis. The question Oberholster gets most often is how to measure smoke exposure risk. Burning wood releases volatile phenols that can be absorbed through the skin of the grape within hours and attach themselves to sugars, which down the road can ruin the wine’s flavor. “Unfortunately, this is very, verydifficult topredict,” she said, adding itwill take years to figure out because “you need hundreds of data points to do this.” Some varietals seemtobemore susceptible thanothers, and “the one that stands out a little bit is pinot noir,” Oberholster said. “We don’t specifically knowwhy.” The volatile phenols that can give wine a palate-demolishing smoky character also occur naturally in grapes, and the exact point at which a grape goes bad is the subject of intense research. “Does pinot noir seem more susceptible just because it has a simpler matrix?” Oberholster asked. “Is thematrix such that there’s lessmaskingof the smoke compounds
See SMOKE, Page 8
February 23, 2022 Ag Alert 7
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