Can the use of rootstocks enhance terroir?

During oak wood contact, wine undergoes important modifications that modulate its organoleptic quality and complexity, including its aroma, structure, astringency, bitterness and color. Vescalagin and castalagin are the two main C-glucosidic ellagitannins found in oak wood used for wine aging wood but lyxose/xylose derivatives (grandinin and roburin e) and dimeric forms (roburins a,b, c and d) are also present. The presence of several hydroxyl groups in the ortho-positions at the periphery of the structure of the ellagitannin isomers allows these molecules to undergo oxidation or condensation reactions with other compounds.

Since the 18th century, sulfur dioxide (SO2) is used in winemaking. Added at different steps, its antimicrobial but also antioxidasic and antioxidant properties are very helpful for winemakers. Nevertheless sulfur dioxide has a real potential health impact, particularly for sensitive consumers often highlighted by hygienists. Nowadays, a serious trend for “natural” wines (i.e. produced without any additives), as described by their producers, could be observed on the French market what match with a proliferation of wines elaborated without any sulfite addition. 

Controlling the development of the bacterial population during the winemaking process is essential for obtaining correct wines[1]. Carbonic Maceration (CM) wines are recognised as high-quality young wines. However, due to its particularities, CM winemaking implies a higher risk of bacterial growth: lower SO2 levels, enrichment of the must in nutrients, oxygen trapped between the clusters… Therefore, wines produced by CM have slightly higher volatile acidity values than those produced by the destemming/crushing method[2].

Soils in vineyards are recognized as complex agrosystems whose characteristics reflect complex interactions between natural factors (lithology, climate, slope, biodiversity) and human activities. To date, most of the unknown lies in an incomplete understanding of soil ecosystems, and specifically in the microbial biodiversity even though soil microbiota is involved in many key functions, such as nutrient cycling and carbon sequestration. Soil biological properties are indicative of soil quality. Therefore, understanding how soil communities are related to soil ecosystem functioning is becoming an essential issue for soil strategy conservation. Here, we propose to assess the importance of land-cover history on the present-day microbiological and physico-chemical properties. The studied area was selected in the Burgundian vineyards (Pernand-Vergelesses, Burgundy, France) where land occupation has been reconstructed over the last 40 years. Soil samples were collected in five areas reflecting various land cover history (forest, vineyards, shifting from forest to vineyards). For each area, physico-chemical parameters (pH, C, N, P, grain size) were measured and DNA was extracted to characterize the abundance and diversity of microbial communities. The obtained results show significant differences in the five areas suggesting that present-day microbial molecular biomass and bacterial taxonomic is partly inherited from past land occupation. Over longer period of time, such study of land-uses legacies may help to better assess ecosystem recovery and the impact of management practices for a better soil quality and vineyards sustainability.

AIM: Different heat tests are used to predict a white wine haze risk after bottling. The most used tests are 30-60 min. at 80°C. Nevertheless, there is a lack of information about the relationship between the wine haze observed after such tests and the turbidities observed in the bottles after the storage/transport of the wines in more realistic Summer conditions (35-46°C during 3-12 days)