Aroma characterization of aged cognac spirits: contribution of volatile terpenoid compounds

At a time when the world’s winegrowing industry is having to adapt to a number of challenges, winegrowers are wondering about the consequent changes they will have to make (grape varieties, changes in vineyard and cellar techniques). For winegrowers and consumers alike, there is also the question of how these changes will affect the taste of their wines. This research, based on the study of numerous sources and archives from the 20th century, some of which have never been published before, aims to show that, in the recent past, the winegrowing world has shown incredible resilience in the face of crises, and that the taste and perception of fine wines has changed considerably in 100 years.

La composition fine des raisins de Grenache noir est mal connue. Il est généralement admis une certaine variabilité de comportement de ce cépage qui se manifeste principalement sur la couleur des vins. De nombreux facteurs peuvent être à l’origine de cette variabilité : matériel végétal, pratiques culturales, types de vinification et terroir. Un travail de recherche concernant ce cépage a été engagé dans la Vallée du Rhône.

Consumer expectations are increasingly shifting towards “residue-free wines.” However, from an analytical standpoint, “zero” does not exist. Laboratories often use the quantification limits of analysis methods to signify ‘zero.’ Improved techniques now allow for the quantification of levels that were previously undetectable. This is why we prefer to use the term “unquantifiable residue” rather than “absence of residues.”

Climate change and harvest date decisions have led to the evolution of must quality over the last decades. Increases in must sugar concentrations are among the most obvious consequences, quantitatively. Saccharomyces cerevisiae is a robust and acid tolerant organism. These properties, its sugar to ethanol conversion rate and ethanol tolerance make it the ideal production organism for wine fermentations. Unfortunately, high sugar concentrations may affect S. cerevisiae and lead to growth inhibition or yeast lysis, and cause sluggish or stuck fermentations. Even sublethal conditions cause a hyperosmotic stress response in S. cerevisiae which leads to increased formation of fermentation by-products, including acetic acid, which may exceed legal limits in some wines.

Protein stabilization is an important part of the winemaking process of white wines, and in this work we present the results of protein stabilization of different monovarietal wines (Xarel.lo, Chardonnay, and Muscat) by a continuous stabilizing filtration process using a column packed with zirconium oxide operating in a continuous regime in a closed loop at pilot scale.