Within the vineyard and the winery, a very small world, the microbial world, exists, but its larger function and impact is largely unknown. The functions of the Saccharomyces yeasts in producing alcohol and other organoleptic components of wine, and the contributions (positive and negative) of certain bacterial components, are becoming clearer. However, numerous other vineyard microbes have been identified in the soil, on the wood and leaves, and on the fruit. Indeed, many others can be demonstrated to exist in the wild even though they are not amenable to laboratory cultivation, but the contributions of these other microbial populations, if any, have not been identified. Furthermore, the firmly-held belief that farming practices contribute to the qualities of wine has not been fully rationalized in any scientific way. The impacts of farming practices (sustainable, organic, Biodynamic) may contribute a substantial portion of their perceived influences through their role of regulating the shape of the microbiome. Longitudinal (i.e., throughout the wine grape growing and winemaking processes) and vertical (i.e., throughout various terroirs and wine grape growing strategies) studies are called for to understand these impacts on the microbiome and how altering the microbiome impacts qualitative components of wine. Although the concept of “microbial terroir” has been discussed for more than a decade, questions such as where the most important microbial reservoirs reside, what the role of the non-culturable components of the microbiome is in the soil and the winery, and what are the contributions of soil composition and farming practices, among others, are only beginning to be asked. The goals of this session are to begin the discussion about these questions, introduce the current state of research in this area, and to encourage awareness of the potential impacts of our viticultural and enological practices on the microbiome.

1. Logo here
Influences on Microbial Terroir
in the Willamette Valley
Jeremy Weisz, Ph.D. , Linfield College

2. Acknowledgements
• Shea Gischer and Alexandra Morse led
the research
• Field collections were assisted by:
Carmen Hoffbeck, Clara Prentiss, Tyler
Griffin, Anna Peckham, Vanessa Van
Horn, and the Weisz Family
• Funding provided by the Oregon Wine
Board (Grant #2018-2129) and by
Linfield College

3. Terroir, is formed, at least
partially, by microbes
Every vineyard has a unique
microbiome, but what causes them
to be different?

4. Early studies show that geography
influences the vineyard microbiome

5. Do the activities of the
vineyard managers (the
farming practices) influence
the vineyard microbiome?

6. Methods
• Collect one cluster of grapes per row,
collecting every other row in a block,
up to 5 clusters.
• Return grapes to Linfield, and remove
4 berries per cluster.
• Mash those berries together, and
extract DNA from that mash.
• Send DNA to sequencing facility at
OSU, get sequence data on bacteria
(and now yeast).
• Analyze data for patterns.

7. Vineyard Sampling

8. Two AVAs sampled in 2017

9. 2017 Vineyards
Vineyard AVA Farming
BK Eola-Amity Biodynamic
BT McMinnville Sustainable
CB Eola-Amity Sustainable
MY McMinnville Biodynamic

10. 2017 Diversity Measurements: Significantly
higher diversity in Biodynamic vineyards
p< 0.05

11. 2017 Diversity Measurements: No
significant differences between AVAs
p> 0.05

12. 2017 Results: Farming has greater
impact than geography
p< 0.05

13. Five AVAs sampled in 2018

14. 2018 Vineyards
Vineyard AVA Farming
WL Dundee Hills Biodynamic
DS Dundee Hills Conventional
BK Eola-Amity Biodynamic
CB Eola-Amity Conventional
MY McMinnville Biodynamic
BT McMinnville Conventional
BH Ribbon Ridge Biodynamic
TR Ribbon Ridge Conventional
MT Yamhill-Carlton Biodynamic
SH Yamhill-Carlton Conventional

15. 2018 Vineyards
Vineyard AVA Farming
WL Dundee Hills Biodynamic
DS Dundee Hills Conventional
BK Eola-Amity Biodynamic
CB Eola-Amity Conventional
MY McMinnville Biodynamic
BT McMinnville Conventional
BH Ribbon Ridge Biodynamic
TR Ribbon Ridge Conventional
MT Yamhill-Carlton Biodynamic
SH Yamhill-Carlton Conventional

16. 2018 Diversity: No significant farming
differences, some AVA differences
A
BC BC
BCB
Bars with
different
letters are
significantly
different
(p<0.05)

17. 2018 Data: Significant Differences
based on Farming Practice
p< 0.05

18. 2018 Data: Significant Differences
based on AVA
p< 0.05

19. Drivers of Community Differences
• Six strains of bacteria are biomarkers of the Biodynamic grape
microbiome community*
• The two most significant are an unidentified strain in phylum
Acidobacteria, and an unidentified strain in genus Gemmatimonas.
• Five strains of bacteria are biomarkers of the Conventional
grape microbiome community*
• The two most significant are an unidentified strain in Genus Delftia and
an unidentified strain in Genus Propionibacterium.

20. Take Home Messages
•The microbiomes of wine grapes are highly
variable.
•Variation is driven by geography, and also by
farming practices.
•Microbial terroir can therefore be influenced by
things that vineyard owner can control.

21. Future Research
• Dr. McGuire and I are planning to collaborate in the
future.
• In 2019, we hope to sample 12 vineyards across the
state, looking at both grapes and wine.
• We plan to correlate differences in wine with differences
in the microbiome.

22. Thank you for your time!