Agronomical assessment of a vine « terroir » map: first results in the « AOC » Minervois region

Acidity adjustments are key to microbial control, sensory quality and wine longevity. Acidification with cation exchange resins -in acid cycle- offers the possibility to reduce the pH by exchanging wine cations, such as potassium (K+), for hydrogen ions (H+). During the exchange process, the removal of potassium and calcium ions contributes to limiting the formation of tartrate salts, thus offering an alternative solution to conventional methods for tartrate stability. Moreover, the reduction of wine pH and the removal of metals catalyzers (e.g. iron) could positively impact the wine’s oxidative stability. Therefore, the aims of this work were (a) to optimize the ion exchange process by testing different volumes and concentrations of sulfuric acid (H2SO4) during the acid cycle, (b) evaluate the effects of the ion exchange process on the formation of tartrate salts, and (c) analyze the oxidative stability of the treated wines.

The choice of sites for viticulture depends on natural environmental factors, particularly climate, as grapevines have specific climatic requirements for optimum physiological performance and berry quality achievement. In the Stellenbosch wine-producing region, the complex topography and the proximity of the ocean create a variety of topoclimates resulting in different growth conditions for vines within short distances.

Environmental factors like soil and climate influence grape quality potential. Their impact is often mediated through vine water and nitrogen status. Depending on the color of the grapes (red or white) and the type of wine produced, the desired level of vine water and nitrogen status for optimum wine quality is different. Little investigation has been carried out concerning these factors and their potential influence on sparkling wine quality on two vintages. In this study vine water and nitrogen status were assessed at a very high density and related to grape composition and berry weight. Through statistical analyses, the major factors driving grape quality potential on Pinot noir in Champagne were highlighted.

Context and purpose of the study ‐ An advancement of grapevine phenological development has been observed worldwide in the last two decades. In South Australia this phenomenon is even more accentuated since grapevine is often grown in a hot climate. The main consequences are earlier harvests at higher sugar levels which also result in more alcoholic wines. These are deemed undesirable for the Australian wine industry with consumer preferences shifting towards lower alcohol wines. Vineyard practices can be implemented to control and delay ripening. Amongst them, apical late leaf removal has been successfully applied in Europe to delay ripening by up to two weeks in Sangiovese, Aglianico and Riesling. In those studies, no negative effects were observed on grape colour, phenolics and on the carbohydrate storage capacity of the vines. To date, this technique has not been studied in Australia. In this study late leaf removal, apical to the bunch zone was applied to the variety Semillon for four seasons and compared to an untreated control.

The Casablanca Valley (CV) has a complex topography and is located near the Pacific Ocean. These factors generate important climatic differences in relation to other wine producing zones of Central Chile.