Wine: from vineyard to winery, techniques to fight climate, alcohol excess and impoverished soils

To successfully address current market challenges, it is necessary to adopt new strategies and production techniques in both vineyards and wineries to cope with climate change, which affects vine physiology, also increasing sugar levels in grapes and alcohol content in wines, while reducing the use of plant protection products - which some viticulture practices still rely on heavily, and counteracting the ongoing depletion of soil organic matter and vitality. These issues, among others, were at the center of the Assoenologi Congress No. 79, held in recent days in Conegliano, in the heart of the Conegliano Valdobbiadene Prosecco Superiore DOCG hills.
Michele Faralli from the University of Trento provided a synthesis of the main impacts of climate change on viticulture. “Over the past four decades, the climate has changed viticulture in Trentino, as in many other European wine regions - stated Faralli - causing significant transformations in the vineyard phenological development, productivity, and quality. Analysis of meteorological and phenological data from 1986 to 2022 in Trentino highlights some key trends. Annual and seasonal temperatures (winter, spring, and autumn) have increased significantly, especially during winter and spring months. Similar phenomena have also been documented by international studies (Ipcc - Intergovernmental Panel on Climate Change, 2021), reporting a global average increase of about +1.1 Celsius degrees compared to the pre-industrial era. Bud break and flowering now occur up to 10 days earlier than in the 1980s. This advance accelerates the entire vegetative cycle, exposing plants to greater risks of late frosts and heat stress. Regional studies and publications confirm that climate warming advances phenological stages in all major European wine regions. The impact on quality and productivity is reflected in faster ripening, lower acidity, and altered aromatic profiles of wines. Some traditional varieties suffer from water and heat stress, while yields may decrease in extreme years”. In this scenario, implementing adaptation strategies is crucial. “The upward shift of vineyards is already a reality - explained Faralli - between 2001 and 2021, there has been a migration towards higher altitudes, with abandonment of areas below 600 meters and an increase in plantings above 800 meters. To mitigate the effects of global warming, varietal choice and genetic selection help introduce heat-resistant varieties or those with longer growth cycles, while advanced agronomic management, such as shading, supplemental irrigation, and soil management, helps reduce climate-related stress. Looking ahead - concluded Faralli - according to climate projections (Ipcc Ar6), warming will continue to influence viticulture, making the adoption of sustainable strategies essential to maintain quality, typicity, and productivity”.
Climate evolution is therefore reshaping viticulture, and new winery practices are also needed to address it. “Climate change and increasingly higher temperatures are leading to earlier grape ripening with a strong accumulation of sugars, resulting in musts with very high potential alcohol levels and wines that often exceed 14-15% alcohol  - explained professor Viviana Corich from the Department of Agronomy at the University of Padua -  at the same time, consumers are becoming increasingly more health-conscious and aware of the negative implications associated with alcohol consumption. The trend toward lighter, fresher products with lower alcohol content, or, in the most recent trends, alcohol-free wines, is growing. To reduce alcohol levels during fermentation, it is necessary to prevent each gram of sugar from being converted into ethanol: the microbiological approach for this purpose mainly involves the use of non-Saccharomyces yeasts and, under appropriate conditions, certain strains and species of the Saccharomyces genus that are less efficient in fermentation, that is, less efficient in converting grape sugars into alcohol. By integrating the use of Saccharomyces cerevisiae with non-Saccharomyces yeasts, it is possible to achieve a reduction in alcohol content of around 1-2%, and under particular conditions up to 3%. It is therefore clear that the use of yeasts alone cannot solve the problem of drastically reducing alcohol levels in wine; however, it can work in synergy with enzymatic and physical techniques for removing sugars, and therefore alcohol. Furthermore, the use of non-Saccharomyces yeasts, in addition to reducing alcohol, can impart interesting varietal and fermentation aromas”.
And, looking to the future, forecasts include, on the one hand, the selection of yeasts capable of delivering significantly lower alcohol yields, also thanks to “adaptive evolution at the laboratory scale” - an innovative approach to obtaining genetically improved strains without resorting to genetic modification (Gmos) - on the other hand, there is also the use of microbial consortia with which some “proxy wines” are produced (for example, kombucha-based products), which can serve as a source of inspiration for the formulation of innovative products with strong health-oriented characteristics in the field of winemaking.
The intervention by Riccardo Velasco, who led the Crea-Ve for nine years and was recently appointed director general of the Mach Foundation in San Michele all’Adige, focused on new varieties and clones obtained through Assisted Evolution Techniques (Aets), and on the methods of genetic improvement used to obtain them. Aets, in particular, have recently been the subject of intense discussions among the European Parliament, Council, and Commission within the framework of the so-called Trilogue. The preliminary agreed text distinguishes two main categories of products: Category 1, relating to plants with minimal genetic modifications comparable to spontaneous mutations. According to the initial agreement, these aren’t considered Gmos and are therefore not subject to labeling or traceability requirements for the final consumer. The only exception concerns a technical requirement for nurseries or farmers, who must be aware of the nature of the vine cutting being purchased. Category 2, on the other hand, includes plants with more significant genetic modifications, for which the same traceability and authorization rules applicable to traditional Gmos apply. The rationale behind this distinction is that Category 1 products are comparable to genetic variations that could occur spontaneously in nature, although in this case they are induced through specific proteins. “European authorization for new genomic techniques (Ngts, as they are referred to in the EU, ed) is at an advanced stage - Velasco told WineNews - the promise of approval by May was not fulfilled, but it is expected that by June a new European regulation will be adopted that will require Member States to take a clear position and establish coherent national rules, as harmonization at the EU level will become binding. In Italy, within the field of agricultural genetics, we have adopted a very strict protocol, considered by many to be more restrictive than the European regulation itself”.
Currently, authorizations are limited to Category 1 Aets, namely those derived from targeted mutagenesis without stable insertion of exogenous Dna. In these plants, no external Dna remains in the final sequence; the protein used for mutagenesis is degraded by the cell and does not persist. These products are therefore genetically identical clones of the original varieties, with mutations comparable to natural ones, and for this reason they do not require specific labeling and are not classified as Gmos under Law 18/2001, since they do not contain foreign Dna. Conversely, the introduction of Dna from sexually compatible species (cisgenesis), belonging to the pangenome of the same species, means that Category 2 Aets may contain traces of minimal external Dna (up to 20 nucleotides are tolerated) and, for this reason, require labeling and traceability. “European regulation - continued Velasco - will define tolerance thresholds and precise criteria to distinguish between these categories. There are implications for the protection and commercialization of these vines that will need to be resolved”. The legal and commercial protection of these products is complex: Category 1 Aet clones, being equivalent to natural mutations, may prove difficult to protect as new varieties. Protection may instead be granted through patents for inventions rather than plant variety rights. Without protection, their dissemination could be limited by the very producers of the clones, who would otherwise risk having no economic return. To ensure market exclusivity, varietal clubs (as in the case of Pink Lady apples, ed) and Dna identification systems (fingerprinting) could be adopted”. Thus, while the new European regulation on Aets aims to promote innovation by reducing the regulatory burden for mutations equivalent to natural ones, it also introduces significant complexities regarding commercial protection and the classification of clones.
There are, however, also numerous cultivation techniques to improve soil quality and promote carbon accumulation, and therefore organic matter. “A series of sustainable practices, applied in synergy, can produce significant results  - explained Lorenzo Furlan, from the “Innovation and Experimentation” directorate of Veneto Agricoltura, the instrumental body of the Veneto Region that supports regional policies in the agricultural, agri-food, forestry, and fisheries sectors -  practices which start with precision agriculture and advanced management models, which today make it possible to provide crops with exactly what they need at each moment, minimizing waste and environmental impact. Diversified crop rotations increase biodiversity and the stability of agricultural systems. Scientific literature clearly shows that the more complex a system is, the more stable it is: this applies to both agricultural production and vineyards”.
Experiments by Veneto Agricoltura have shown that the natural process of carbon sequestration in soil is slow. “In 7 years - Furlan noted - we have observed minimal progress. To accelerate the restoration of soil sustainability, we integrate the ‘basic’ package with additional practices, such as the addition of high-quality organic matter and the stimulation of beneficial microflora, capable of fixing nutrients and improving overall fertility. Compost, manure, well-managed slurry, and properly treated organic materials help rebuild soil structure. A concrete example is the adoption of modern agroforestry systems: combining trees and herbaceous crops on farms can sustainably produce more biomass. On this basis, Veneto Agricoltura has developed a project covering 600 hectares, dividing the areas into homogeneous zones and applying the principles of precision agriculture. Each zone hosts both conventional and conservation management, allowing repeated comparisons over several years”.
These are just a few examples of how the wine sector, one with a millennia-old history and strong tradition, continues to look toward innovation, as it has always done, to shape its future.