Over the last several decades winemakers in the United States have been negatively impacted by the increased intensity of proximal wildfire events. Unlike most food and beverage crops, wine has shown to be particularly sensitive to compounds derived from the ambient smoke at even low densities, often acquiring a medicinal, “ashy” or “burnt rubber” flavors or aromas. The wine industry has long sought more efficient methods of preventing or mitigating the negative sensory characteristics associated with smoke exposure, and unfortunately, some studies have disagreed on the major chemical compounds imparting these sensory characteristics. To develop more targeted approaches to ameliorate the impacts of smoke on wine, this study was developed to inventory the chemicals derived from smoke by chemically labeling a fuel source. Barley, Hordeum vulgare, was exposed to 13C-lablelled CO2 (13CO2) using pulse-labeling techniques in an enclosed environment for 10 days over two weeks. The barley was subsequently dried to constant weight and separated into randomized 5 g bundles. The increased 13C content was evaluated using isotope ratio mass spectrometry (IRMS). This method yielded 13C/12C content as high as 3186.90 ± 737.22‰ relative to VPDB and 4.47 ± 0.75% 13C content compared to 1.10% 13C content of untreated barley. Dried barley bundles were burned and piped “cold” to sealed tents containing Pinot noir or chardonnay grapes from the Woodhall vineyards in Willamette Valley, Oregon. Each replicate of grapes was exposed to a smoke density of 20-100 mg/m3 for smoke particle &gt;1 μm. Standard wine-making methods for the respective styles were employed followed by chemical evaluation using GCMS, HPLC, and 13C-NMR to determine compounds derived from 13C-labelled smoke source.

Incorporation of 13C as a chemical label for smoke fuel used for smoke affected wine studies

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.