The production of white-skin-macerated wines without sulphur dioxide (SO2) has increased in recent years, although it presents challenges such as uncontrolled alcoholic fermentation (AF) or malolactic fermentation (MLF) and the production of undesirable compounds. Fumaric acid (FA) is being explored as an alternative to SO2 due to its antimicrobial and acidifying properties. This study evaluated the effects of vinification type (white skin contact vs. conventional white wine) and different treatments: (i) control without additives, (ii) 0.6 g/L FA, and (iii) 40 mg/L SO2. After AF, MLF was conducted under three conditions: spontaneous fermentation and two inoculated trials with 106 cells/mL of Oenococcus oeni, one without lees and one with 1 g/L lees from AF. Yeast and lactic acid bacteria dynamics during AF were monitored, along with chemical composition, colour, and sensory characteristics of the wines. Results revealed that the development of AF and final wine compositions were influenced by the vinification type and treatment. During MLF, residual FA from the AF was able to delay its progress but was not sufficient to completely inhibit it. The sensory analysis did not reveal significant differences between treatments. Fumaric acid is a viable alternative to SO2 for managing MLF in high-pH white wines (including those with skin maceration), allowing for lower SO2 concentrations and enhanced freshness without impacting sensory quality.
García-Viñola et al. (Thu,) studied this question.