Comparaison de pratiques d’acidification en vinification en rouge : impacts sur l’acidité, les caractéristiques chromatiques et organoleptiques des vins

Abstract

Results reveal differences for the acidifying level in seven studied approaches. Physical methods enable a precise pH decrease with an advanced automation of equipment. Chemical acidifying level is variable. Tartaric acid is the one that modifies the most pH but foreseeing the level of acidifying remains uneasy because of tartaric precipitations. Malic and lactic acids seem to play more on total acidity increase than on pH decrease. Fumaric acid has a limited impact on both total acidity and pH. Wine color is impacted another way, depending on which technique of acidifying is used. Chemical acidifying increases the coloring intensity of wines with pH increase. Under the assay conditions, using ions exchanging resins lead to a drop of polyphenols and results in a Modified Coloring Intensity (IC’) reduction. However chromatic features are clearly improved with physical techniques which develop brighter colors (Chroma increase). pH decrease has significant results on the content of aromatic molecules. Low pH stimulates the creation of ethyl esters and protects norisoprenoids in rising the proportion of molecular sulfur. In organoleptic terms, sour perception, aromatic intensity (nose and mouth) and aromatic descriptors are increasing for the batches that have been acidified. Yet there are differences according to the acidifying method used. The rise of sour perception has influences on taste with a lower volume for acidified wines.