Which method can be used to avoid malolactic conversion?

Storing wine at cool temperatures can effectively inhibit malolactic conversion. Malolactic fermentation is a process where malic acid in the wine is converted to lactic acid by lactic acid bacteria. Cooler temperatures slow down the metabolic rates of these bacteria, thereby reducing their activity and preventing malolactic fermentation from occurring. This method is particularly useful for winemakers who want to maintain the vibrant acidity and fresh character of the wine, especially in white wines.

In contrast, the other methods listed can encourage malolactic fermentation or do not directly influence the bacteria responsible for the conversion. For instance, raising fermentation temperatures often stimulates yeast activity and can also promote malolactic fermentation if lactic acid bacteria are present. Using wild yeasts can introduce a variety of microorganisms, including those that may lead to malolactic fermentation. Lastly, adding yeast nutrients is typically aimed at enhancing yeast growth and fermentation efficiency, which does not have a direct relationship with malolactic conversion prevention.