What you need to know about the acid in the wine?

Naturally present in grapes, acid in wine is essential to flavor and balance. More acidic wines tend to have a crisp, palate cleansing effect characteristic in many white wines. The inky, mouth-coating sensation produced by many reds is typical of low acidity.

Controlling acidity is crucial to great wine. There are several ways in which winemakers regulate the acidity in a wine, both in the growing phase and in the winemaking phase.

In general, grapes grown in cooler climates retain more acidity than grapes in warmer climates. If it’s a long, hot summer, early harvesting may be necessary to avoid overly ripe grapes with too much sugar and insufficient acid. On the other hand, grapes in very cool climates can potentially have too much acid.

Accordingly, sunlight exposure is a vital contributor to acid in wine. Vines planted on a hillside, for example, will receive different amounts of sunlight during different parts of the day, depending on which direction the hillside is facing. Exposure can also be altered by adjusting the foliage on the vine. These are some of the many factors that vineyard managers must consider to control acid in wine.

Winemakers can also affect acid during and after fermentation. To increase acidity, the winemaker can simply add acid. Decreasing acidity is more complicated. A common way of achieving lower levels of acidity is through a chemical process known as malolactic fermentation.

What you need to know about the acid in the wine?

Fermentation refers to the process were yeast consumes sugars and produces alcohol and carbon dioxide. Malolactic fermentation is different in that Leuconostoc bacteria cultures, not yeast, is introduced during or following basic fermentation. This bacteria converts tart malic acid into softer lactic acid, reducing perceived acidity and leaving a rounder profile.

Malolactic fermentation is generally used for red wines but is also used in some whites, especially ones from cooler climates. The flavor profile in Napa Valley Chardonnay often described as “buttery” is a result of this process.