Malolactic fermentation From bad to good There are some who try to stop it and others who try at all costs to get it started. Malolactic fermentation is a natural process due to the action of certain bacteria which change malic acid (which has a much stronger taste) into lactic acid which is much less aggressive. Malolactic fermentation starts after the alcoholic fermentation, in some cases immediately afterwards, sometimes in the spring or at the beginning of the summer after the grape harvest. It is the temperature of the wine, whether natural or controlled, which sets off this fermentation, but a great deal depends on the initial acidity of the grapes. With malolactic fermentation the wine starts to change its organoleptic character; the colour develops a less lively tone, the perfumes gain new subtleties and the taste becomes rounder and fuller. Producers who want to start up this process are those who want to make full-bodied red wines suitable for ageing or at least major wines. It is used for almost all red wines but also still whites and rosés which have body and fullness on the palate. Those who wish to avoid it are the producers who want fresh, easy-drinking wines, especially if they are semi-sparkling or sparkling, where high acidity gives these wines their characteristic bouquets.