PROGRESS OF STUDIES OF LEES ORIGINATING FROM THE FIRST ALCOHOLIC FERMENTATION OF CHAMPAGNE WINES

Abstract

Champagne wines are produced via a two-step process: the first is an initial alcoholic fermentation of grape must that produces a still base wine, followed by a second fermentation in bottle – the prise de mousse – that produces the effervescence. This appellation produces non-vintage sparkling wines composed of still base wines assembled from different vintages, varieties, and regions. These base wines, or “reserve wines,” are typically conserved on their fine lies and used to compensate for quality variance between vintages (1). Continuously blending small amounts of these reserve wines into newer ones also facilitates preserving the producer’s “house style.” Some of these wines therefore possess the potential to age and maintain their organoleptic quality for even decades. Despite this potential, while the prise de mousse and final product have been extensively studied, far less research has been realised on the Champagne base wines and lies.

The aim of our ongoing study is to apply a multi-disciplinary strategy to study Champagne base wine lies. First, lies production was standardized on a laboratory scale at differing volumes (125 mL, 1 L, 5 L) for both synthetic solutions modelled on Champagne grape musts, and actual musts originating from the region. Confocal microscopy was then utilised to observe yeasts cells present in the wines and lees, as well as any enzymatic activity, creating a visual reference of autolytic dynamics over a one-year period. Simultaneously, these solutions were analysed for volatile odorous compounds and their precursors, including dimethyl sulphide (DMS,) monoterpenes, and heterocycles. Particular attention was given to amino acid concentrations, as previous studies show the importance of lees and amino acid content on ageing potential of reserve wines(2). Initial results show a dynamic evolution of volatile compounds in the early stages of aging, highlighting the potential contribution of lies to the longevity of still base wines. In addition, chemical analyses revealed unexpected data concerning the production of DMS in wines. This tandem approach allowed a preliminary analysis of Champagne reserve wine kinetics and the corresponding release of volatile compounds during the initial stages of lees aging.