Time course of the evolution of malic and lactic acids in the alcoholic and malolactic fermentation of grape must by quantitative 1H NMR (qHNMR) spectroscopy.

Quantitative NMR can be used to monitor several processes that take place in the transformation of the must of wine grapes. The study described here focused attention on monitoring of the malic and lactic acid levels during the alcoholic and malolactic fermentation processes. The method allows the simultaneous quantification of both acids through a range of 1-3.2 mmol/L. The effectiveness of each process was assessed and compared by carrying out precise analyses using enzymatic methods.