Terroir is the term for the unique blend of a vineyard’s soils, water and climate that impacts the flavor and quality of wine. These unique microbial inputs are key to regional wine fermentations.
A new study from UC Davis, MicroTrek, Inc. and Constellation Brands Inc. offers evidence that grapes and the wines they produce are also the product of an unseen but fairly predictable microbial terroir, itself shaped by the climate and geography of the region, vineyard and even individual vine.
Results from DNA sequencing revealed that there are patterns in the fungal and bacterial communities that inhabit the surface of wine grapes, and these patterns are influenced by vineyard environmental conditions.
To examine the microbial terroir, the researchers collected 273 samples of grape “must,” –- the pulpy mixture of juice, skins and seeds from freshly crushed, de-stemmed wine grapes. The must samples were collected right after crushing and mixing from wineries throughout California’s wine-grape growing regions during two separate vintages. Each sample, containing grapes from a specific vineyard block, was immediately frozen for analysis.
It isn't just the grape or even the soil, microbes matter too. Credit: Shutterstock
The researchers used a DNA sequencing technique called short-amplicon sequencing to characterize the fungal and bacterial communities growing on the surface of the grapes and subsequently appearing in the grape must samples.
They found that the structure of the microbial communities varied widely across different grape growing regions. The data also indicated that there were significant regional patterns of both fungal and bacterial communities represented in Chardonnay must samples. However, the Cabernet Sauvignon samples exhibited strong regional patterns for fungal communities but only weak patterns for bacterial communities.
Further tests showed that the bacterial and fungal patterns followed a geographical axis running north-south and roughly parallel to the California coastline, suggesting that microbial patterns are influenced by environmental factors.
Taken together, these and other results from the study reveal patterns of regional distributions of the microbial communities across large geographical scales, the study co-authors reported.
They noted that it appears that growing regions can be distinguished based on the abundance of several key groups of fungi and bacteria, and that these regional features have obvious consequences for both grapevine management and wine quality.
“The study results represent a real paradigm shift in our understanding of grape and wine production, as well as other food and agricultural systems in which microbial communities impact the qualities of the fresh or processed products,” said senior author Professor David Mills, a microbiologist in the Department of Viticulture and Enology and Department of Food Science and Technology at U.C. Davis. He noted that further studies are needed to determine whether these variations in the microbial communities that inhabit the surface of the grapes eventually produce detectable differences in the flavor, aroma and other chemically linked sensory properties of wines.
Gaining a better understanding of microbial terroir, growers and vintners may be able to better plan how to manage their vineyards and customize wine production to achieve optimal wine quality.
Collaborating with Mills were graduate student Nicholas Bokulich of the UC Davis Department of Viticulture and Enology; John Thorngate of Constellation Brands Inc.; and Paul Richardson, CEO of MicroTrek Inc., a company founded to provide microbial mapping services to help vintners understand this phenomenon. Constellation Brands Inc. provided in-kind support for the study through sample and metadata collection.
Citation: Nicholas A. Bokulich, John H. Thorngate, Paul M. Richardson, and David A. Mills, 'Microbial biogeography of wine grapes is conditioned by cultivar, vintage, and climate ', PNAS 2013 ; published ahead of print November 25, 2013, doi:10.1073/pnas.1317377110
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Pseudoscience Creeping Into Your Conference? A Case In GMOs And Glyphosate
- My Thoughts On The LIGO-VIRGO Result
- Beyond Diamonds And Gems: The World's Rarest Minerals
- Henri Poincaré Predicted The Existence Of Gravitational Waves As Early As June 5, 1905
- Gravitational Waves? Watch the LIGO press conference at 10:30 Eastern.
- The 10 catastrophic mistakes virtual reality firms are making
- When Machines Can Do Any Job, What Will Humans Do?
- "That reminds me of the chemiosmotic war that followed Peter Mitchell's publication of his theory..."
- "The American Physical Society (APS) has allowed physics crackpots to attend conferences for years..."
- "A further comment on the meaning of Poincaré's prediction about gravitational waves : the classical..."
- "Dear Tomasso I have a simple question: What is the probability of a chirped wave train of 20ms..."
- "Ciao Giulio - I work on the LIGO and Virgo instruments, I can try to explain. The arms in LIGO..."
- Beard Microbiology: Grubby Hipsters May Be On To Something
- Water Tops the List of Health Concerns for Competitive Eaters
- Natural Flavors Are More Radioactive Than Artificial Ones.
- Bariatric Surgery Beneficial Even for Older People
- Opiates No Better at Easing Knee Osteoarthritis Pain
- BRCA Tests Increasing for Younger Breast Cancer Patients
- Dark matter scientists on brink of discovering elusive particles
- Science responds to globalized disease threat to farms and food systems
- Americans' support for science remains strong
- Loss of sleep during adolescence may be a diabetes danger
- Study of cognitive development in deaf children revisits longstanding debate