Malolactic fermentation deacidifies the wine by converting the "harsher" diprotic malic acid to the softer monoprotic lactic acid. The different structures of malic and lactic acids leads to a reduction of titratable acidity (TA) in the wine by 1 to 3 g/l and an increase in pH by 0.3 units. Malic acid is present in the grape throughout the growing season, reaching its peak at "veraison" and gradually decreasing throughout the ripening process. Grapes harvested from cooler climates usually have the highest malic content and have the most dramatic changes in TA and pH levels after malolactic fermentation.