Differentiating sparkling press fractions objectively

Common practice for high quality sparkling wine production is to separate press fractions as used in méthode champenoise. Champagne production has shown there to be a quality difference between free run and pressings, however little research has quantified the differences between the fractions objectively. Subjective sensory differences are evident between fractions, and winemakers keep at the very least free run (cuvée) and pressings (taille) separate, but often also several more fractions during pressing. In the current study, Chardonnay and Pinot Noir fruit was gently pressed using a whole bunch press, similar to those used for sparkling wine production. Free run juice and pressings juice was separated at pressing time, analysed and then vinified separately to the base wine stage. Principal component analysis of the phenolic fingerprints, generated by UV spectroscopy of both the juice and the base wines, separated free run from pressings and Chardonnay from Pinot Noir. The importance behind the ability to differentiate these fractions is the potential to develop objective measures of sparkling wine quality, both at the juice and base wine stages.