WAC–IVAS 2026 – Session 1: Chemical reactions in wine (stability, aroma, aging…)

Oenological closures play a crucial role in the preservation and evolution of still and sparkling wines in bottle.

Orange wines, defined as white wines produced with prolonged skin maceration, have recently gained increasing attention due to their distinctive sensory profile and potential functional properties.

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The colour stability of red wine is a desired and complex feature affected by anthocyanin structure and concentration, copigmentation phenomena, and interactions with other wine macromolecules, such as polysaccharides.

Wine matrix is a complex and continuously evolving medium. The impact of oxygen in wine evolution is a vital factor that critically affects key organoleptic properties such as color or astringency.

Hydrogen sulfide (H2S) and methanethiol (MeSH) are the primary compounds responsible for the reduction fault in wine.

Yeast derivative products (YDP) are increasingly used in winemaking for their impact on sensory properties, yet their molecular interactions with wine aroma compounds remain poorly understood.

Aroma compounds are critical for wine sensory quality, yet their concentration and expression can be altered during winemaking and aging by sorption onto solid surfaces such as oak wood, yeast lees, or yeast derivatives (1-3).

Flavor perception arises from complex interactions between volatile aroma compounds, non-volatile tastants, and the surrounding food matrix, ultimately translated into specific aroma and taste receptor responses.

Phenolic compounds play a key role in wine sensory properties, traditionally associated with colour, taste attributes (e.g., bitterness) and trigeminal sensations such as astringency.

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Oenological closures play a key role in wine aging by influencing oxygen ingress, enabling a slow oxygen supply that can favour wine maturation.

Colloidal equilibria involving phenolic compounds are essential for the stability and sensory properties of red wines.

Prié blanc is an ancient white grape variety (Vitis vinifera L.), native to the Aosta Valley alpine region in North-West Italy, growing own-rooted in heroic viticulture at altitudes between 900 and 1200 m asl where it can ripe properly with short growing seasons.

Tartrate precipitation (potassium hydrogen tartrate, KHT, and calcium tartrate, CaT) is a major source of wine instability, particularly concerning sparkling wines, where it may induce gushing.