WINETECH Technical Yearbook 2021

VITICULTURE RESEARCH | JULY 2021

Understanding the “terroir effect” (PART 3)

BERNARD MOCKE: Private consultant KEYWORDS: Terroir, aroma typicity.

THE TASTE OF ANY GIVEN WINE, regard- less of cultivar, is inextricably linked to its origin. Environmental factors, such as soil and climate, influence organoleptic charac- ters and by deconstructing measurable soil and climate parameters, this influence on a wine’s typicity can be better understood. Part 1 and 2 of this three-article series introduced the terroir effect on wine aroma, gave an overview of the main aromatic grape and wine aroma compounds, and provided insights on how terroir shapes grape and wine aroma expression. In Part 3, the conclusion of this series, the focus is on the prediction and management of aroma typicity as influenced by specific terroir. INTRODUCTION It has become evident that there is a clear link between wine typicity and localised soil and climatic conditions. Thanks to technology, comprehensive databases

are available on parameters such as air temperature, radiation, rainfall, soil water holding capacity and vine nitrogen status, all of which can be spatialised and quantified at vineyard scale. It has been suggested that by selecting material appropriate to the soil and climatic conditions, properly managing parameters such as vine water and nitrogen status and influencing bunch zone microclimate by means of canopy management, site specific terroir expression can be maximised. It is said that you can make bad wine from good grapes, but not good wine from bad grapes. This old adage once again brings us back to the vineyard where every wine’s journey begins. TERROIR’S INFLUENCE ON GRAPE AND WINE AROMA The hierarchy of terroir factors and choosing a variety

The influence of climate and soil is expressed through the grapevine variety. Due to the uniqueness of aromatic composition, the terroir effect should be considered separately for Cabernet Sauvignon, Syrah, Merlot, Riesling and Sauvignon blanc – these varieties are the focus in this article as they are some of the most planted varieties in the world and the compounds giving them their aromatic profiles are well known. Due to length constraints, not all information can be discussed and the reader is encouraged to study the original cited article, namely “Recent advancements in understanding the terroir effect on aromas in grapes and wines” ( OENO one 4, 985-1006). Temperature and radiation as climate components Temperature during grape ripening plays a major role in the aroma typicity of

wine. It was shown that a considerable variability in temperature structure in grape-growing areas can exist at both the mesoscale and microscale. Radiation varies depending on cloud cover and increases with temperature. Cool temperatures during grape ripening increase IBMP and 1,8-cineole, with IBMP an important component in perceived freshness in Sauvignon blanc. Sauvignon blanc grown in warm areas shows more tropical fruit aromas and less asparagus and boxwood aromas. Low temperatures result in higher levels of (-)-rotundone in Syrah.

WINETECH TECHNICAL YEARBOOK 2021 | 22