Ascorbic acid (vitamin C) is a powerful antioxidant that is used during the manufacte process to quickly eliminate any presence of dissolved O₂ that could oxidize phenolic compounds, especially those derived from cinnamic acid, which produces a darkening of the wine. Ascorbic acid very efficiently converts said oxygen into hydrogen peroxide that is subsequently neutralized by the SO₂ present in the wine (thus, it is recommended that the wine contains between 30 and 50 mg/L of SO₂ before the addition of ascorbic acid to be effective in the elimination of hydrogen peroxide formed). It also prevents oxidation of iron ions as prevention of iron case. An excess of ascorbic can negatively affect the color of the wine and its subsequent evolution.