St. Louis, Mo.—The modern, post-Prohibition wine industry is still less than 50 years old in many states east of the Rockies. For states in the northern tier, where winter temperatures often drop well below -15° F, the industry is closer to 30 years old. Yet today wine is made in all 50 states, due in part to the development of cold-hardy grapes developed at places like the University of Minnesota.

The expansion of the eastern wine industry was reflected in a different way at the annual conference of the American Society for Enology and Viticulture-Eastern Section held July 18-21 in St. Louis. In addition to the researchers, extension advisers, grapegrowers and winemakers that make up the majority of conference attendees, 32 students from 15 universities participated in this year’s meeting of the Eastern Section.

It wasn’t that many years ago that if a young woman or young man wanted to learn how to grow grapes or make wine, the options for a college or university program were limited. The University of California, Davis, and California State University, Fresno, offered degree programs, while most other colleges and universities (including Cornell University) taught only a few courses in their Food Science or Horticulture departments.

At the meeting in St. Louis, there were 14 students from the University of Wisconsin to Auburn University in Alabama, and from Laval University in Québec City to the University of Nebraska. Each student presented a 15-minute talk about their research in hopes of receiving the award for best student enology or viticulture paper. Another 18 students prepared 3-minute (strictly enforced) talks about the research summary posters placed on walls and window shades around the meeting room. There were more presentations about viticultural than enology, prompting one winemaker to note, “There’s more money for agricultural research than for alcohol, and wine is alcohol.”

Eastern Section’s underlying theme: technology
Perhaps the most wide-ranging and global view of the evolution of viticulture and enology as a result of changes in technology and the environment was presented by Jean-Philippe Roby, during his talk, “Defining, Measuring and Managing ‘Terroir,’” at the symposium “Adapting and Adopting: The Future of Grape and Wine Production” on the last day of the Eastern Section conference. Entire books have been written about the concept of terroir, but Roby defined the topic in such a way that no matter where a conference attendee lived, he or she could understand the meaning of terroir as it relates to a given place and how to manage it within that local environment.

Roby, associate professor at the Bordeaux Sciences Agro, ISVV (Vine and Wine Science Institute of Bordeaux), looked at terroir not as a static concept, but as an inter-related ecosystem that includes specific soil features (type, water retention, minerals, nitrogen), topography, climate (rainfall, temperature), landscape characteristics and biodiversity features as well as cultural practices including vinification and aging techniques that affect quality and typicity of a wine.

His definition of terroir leads to a question: How can one measure the vineyard behavior at the local level, using information about the terroir, to optimize the quality and yields? The answer is to measure the technical aspects (or parameters) of the terroir. For example, weather stations have been miniaturized and cost reduced, which puts such technology within the budgets of smaller vineyards. The data collected allows for the spatialization of weather factors, especially temperatures, so growers can see the differences in the micro-climates of different plots within the vineyard. Among other things, that information may help a grower determine whether to harvest one area sooner than another.

The onset of a vineyard’s phenological stages also can be modelized. Graphs can be used to show the effect of the climate, the soil and the type of the vine on véraison date, on the sugar content of the grapes and on the pre-dawn water potential. The water deficit effect on the vine—the cessation of growth, berry weight, malic acid content, anthocyanins content—all can be measured and used to evaluate the water status of the vine. The nitrogen status of the vine can be mapped as well.

The factors of climate (temperature and water status) and soil (temperature, water and mineral/nitrogen status) interact with the vines and cultivation techniques, all of which raises another question. Roby asked, “How can we manage the vineyard at the parcel level, relying on terroir knowledge to optimize the quality and yields?”

According to Roby, it is the role of the winemaker and the “actors” in the sector to make a choice of plots, from a soil and climate standpoint. Roby pointed out that “if the soil is different in different zones of the vineyard, it will affect the behavior of the plant.” As for climate zones, temperatures can vary at different elevations, as can the water availability.

A major decision for winemakers is what varieties of grapes to plant. In France, the choice has been limited, but there are forgotten or abandoned grape varieties that could be planted to adapt to environmental changes. “After phylloxera in the 19th century,” Roby commented, “France chose grafting vinifera to rootstocks. But because of the Atlantic climate, vineyards need to be sprayed 12 to 14 times per year for downy mildew. We must cut down or eliminate pesticide use, which is a huge challenge.”

According to Roby, there is interest in new varieties, hybrids and clones, and the preservation of that biodiversity will hopefully allow vineyards to adapt to environmental changes. Rootstocks will also have to be more adapted to drought and to delaying the phenological cycle so that vines have more vigor.

Growers will need to pay attention to water and nitrogen to control vigor and consider different ways to manage weeds in the vineyard while maintaining the soil below the row without the use of herbicides. One method that is being tried is organic geo-textiles applied below the vine row to preserve water and reduce herbicide use.

In conclusion, Roby noted that the concept of terroir is in perpetual evolution. “It’s a work in progress,” but that the tools to manage terroir do exist. Not all changes will come quickly or easily, and he acknowledged that it “will take a generation to get acceptance of new clones and hybrids (in France). It may take 15 to 20 years.”

Roby also invited interested growers, winemakers and researchers to attend Terroir & Vineyard Management, a “training course for international professionals dealing with the concept of terroir and the way to manage the vineyard in order to optimize terroir expression.” The meeting will be held March 6-10, 2017, in Bordeaux, France.

More on the theme of technology
Many of the talks during the regular sessions of the Eastern Section meeting that preceded Thursday’s symposium reflected or were based on the ability to adapt to and/or adopt modern technology. Fritz Westover, the first of Eastern Section’s invited industry experts, addressed the issue of how to impact the decision-making of growers in an era of science and technology overload.

Westover is the owner of Westover Vineyard Advising in Houston, Texas, and specializes in vineyard consulting, research and education in the south and southeastern United States. As a viticulturist, he has experience growing many varieties grapes, from vinifera to hybrids to Muscadines.

He first cited some of the traditional ways of communicating information to growers: direct contact through field days, workshops and conferences, university websites and trade publications (he is a regular contributor to Wines & Vines). He then looked at some of the tools that growers can now access, and noted that the price of both hardware and software tools is coming down, making it possible for growers with smaller vineyards to have hardware such as remote weather stations with cameras as well as software for record-keeping on a range of details from pesticides to wine additions.

Dr. Andrew Reynolds, professor of viticulture at Brock University, gave two talks about mapping variability in Ontario vineyards, first by proximal sensing technology and by remote sensing with unmanned aerial vehicles (UAV) such as drones. The metrics provided by high-resolution proximal sensing technology, known as GreenSeeker, were correlated with yield components (including yield per vine, cluster weight and berry weight), vine and soil water status, berry composition and winter hardiness. Data from GreenSeeker showed strong correlations with both yield components and berry quality composition variables, and the maps produced for all the variables confirmed the statistical findings. The technology also has been useful in assessing water status, which relates to vine size, berry composition and yield components, and can potentially be used as a variable-rate technology to adjust vine pruning and shoot thinning in the vineyard.

Not as much work has been done in viticulture to assess the usefulness of remote sensing, although Reynolds noted that images from UAVs have shown the development of grapevine leafroll virus symptoms and that both UAV and GreenSeeker have produced maps of similar configurations.

Many people are familiar with Dr. Andrew Walker’s work at the University of California, Davis, to develop grapevines that are resistant to Pierce’s disease, but molecular genetics is being used in other industry projects as well. Dr. Chin-Feng Hwang, associate research professor at Missouri State University, is investigating molecular genetic approaches to improving Norton grapevines. Hwang stated that his goal is to cross Norton with Cabernet Sauvignon to obtain the cold-hardy, disease-resistant traits of Norton with the great wine quality of Cabernet. Phenotyping assays for downy mildew and Botrytis bunch rot resistance as well as rooting ability and sulfur sensitivity have now been identified.

(As a side note to Hwang’s work: Genetic mapping has now shown that Norton and Cynthiana (a name used primarily in Arkansas) are genetically the same grape.)

“Yeast Nutrition is More Than Nitrogen” was the topic of the second invited expert, Dr. Nichola Hall. She is a fermentation specialist at Scott Laboratories in California and currently the first vice president of ASEV. Hall, who earned a Ph.D. in yeast physiology and fermentation science from the University of Abertay in Dundee, Scotland, reviewed the essential nutrients for yeast: macronutrients such as carbon, nitrogen, oxygen, hydrogen, phosphorus, potassium, magnesium and sulfur; and micronutrients including calcium, copper, manganese, zinc (absolutely essential!), nickel and molybdenum.

For a fermentation to be successful, Hall noted, the mineral requirements need to be balanced, as they are co-factors for glycolysis, for increasing yeast tolerance to ethanol, and for regulating ethanol production, cellular growth and the formation of esters.