Project Summary
Previous research in other wine-producing regions of the world has identified at least four different genetic groups of Brettanomyces that cause wine spoilage, with one sulfite-tolerant group of particular concern when found at high frequency. This research will utilize whole-genome sequencing to address the extent to which Oregon vineyards and wineries harbor similar Brettanomyces strains, and through micro-fermentation will evaluate the prevalence of sulfite-tolerance and spoilage potential. Results generated through this work will inform a workshop focused on methods of Brettanomyces detection and control.
Project objectives
- Comprehensively sample for Brettanomyces yeast strains from vineyards and winery-related surrounding environments from at least six collaborating wineries across two
Willamette valley sub-AVAs - Isolate by enrichment culture and identify Brettanomyces yeast strains
- Evaluate spoilage potential of Oregon Brettanomyces strains
- Develop and convene two regional workshops summarizing project results and providing updated guidance on Brettanomyces control
Importance to the Oregon wine community
The proposed research area addresses the strategic pillars of wine quality and foundational research, within the specific areas of:
• Viticulture 3B – the extended vineyard microbiome as a critical component of terroir and its impact on wine characteristics.
• Enology 1D – Develop a deeper understanding of the fungal and bacterial communities present during wine fermentation and aging, their effects on wine quality, and levers for the control of undesirable microbes in wine to minimize microbial defects.
Progress Reports
2021-22: Year 1 Update
In its 2021-22 fiscal year, the Oregon Wine Board of Directors granted $289,000 to researchers for six projects with the potential to advance quality grape growing and winemaking in Oregon. The update below is part of a series to let industry members know about the status of these projects.
Progress so far
During the 2022 harvest, we cryopreserved laboratory-generated aseptic must samples (n=108) from 12 vineyards in two Willamette Valley sub-AVAs (Eola Hills and Dayton – 6 vineyards in each sub-AVA) that share similar viticultural management practices. The sampling strategy was designed in consultation with yeast ecologist Prof. Matthew Goddard (University of Lincoln, UK) to maximize our ability to detect within- and between-region differences for another project that will analyze the overall yeast community structure. This parallel project may provide informative data on yeast species that can serve as proxy indicators for much less abundant Brettanomyces. We will enrich these samples for Brettanomyces isolation prior to the 2023 harvest.
Next steps
Our plan for the 2023 and 2024 harvest seasons is to return to the same vineyards and aseptically collect 216 cluster samples each year for washing and Brettanomyces enrichment. We will also sample from wineries associated with the 12 sampled vineyards during both years, collecting 240 environmental swabs while the cellars are actively processing grapes and 120 barrel samples postharvest. In total, during this project, we will attempt isolation of Brettanomyces from 900 samples.
2022-23: Year 2 Update
In the fiscal year 2022-2023, the OWB committed $359,409 to seven highly ranked viticulture and enology projects that were reviewed and recommended to OWB by its Research Committee comprised of volunteers from across the state.
Progress so far
During the 2022 harvest, we cryopreserved laboratory-generated aseptic must samples (n=108) from 12 vineyards in two Willamette Valley sub-AVAs (Eola Hills and Dayton – 6 vineyards in each sub-AVA) that share similar viticultural management practices. The sampling strategy was designed in consultation with yeast ecologist Prof. Matthew Goddard (University of Lincoln, UK) to maximize our ability to detect within- and between-region differences for another project that will analyze the overall yeast community structure. This parallel project may provide informative data on yeast species that can serve as proxy indicators for much less abundant Brettanomyces. We will enrich these samples for Brettanomyces isolation beforehe 2023 harvest.
Next steps
Our plan for the 2023 and 2024 harvest seasons is to return to the same vineyards and aseptically collect 216 cluster samples each year for washing and Brettanomyces enrichment. We will also sample from wineries associated with the 12 sampled vineyards during both years, collecting 240 environmental swabs while the cellars are actively processing grapes and 120 barrel samples postharvest. In total, during this project, we will attempt isolation of Brettanomyces from 900 samples.
Principal Investigator
Dr. Chris Curtin is an expert in fermentation microbiology, particularly the impact of yeasts on fermented beverage flavor. Prior to joining Oregon State University in 2016, Curtin led biosciences research at the Australian Wine Research Institute, where he was responsible for development of novel yeast strains and strategies to mitigate spoilage by Brettanomyces yeasts. Since joining OSU, Curtin’s laboratory uses ‘omics tools to better understand the role of yeasts and bacteria in a range of fermented beverages, such as wine, beer and kombucha.
