What Is Acidity In Wine?

Let's try an experiment: Pour yourself two glasses of white wine, or head over to your favorite local wine bar and order there. One of them should be a New Zealand Sauvignon Blanc, and the other a buttery Napa Valley Chardonnay. Take a sip of the Sauvignon Blanc first and notice how assertively the salivary glands at the base of your jaw start firing away, making your mouth water. Then take a sip of the Chard, and notice how much less your mouth waters.

That's thanks to the different levels of acidity in each wine.

White wine, it's often said, is built on a spine of acidity, though red wines also have acidity…it's just that their structure is generally more predicated on tannins. Wines that lack enough acidity often taste flat and lack a sense of energy, whereas reds and white with too much acidity can taste off-puttingly tart. In wine as in life, it's all about balance.

Acid is a natural component of fruit, including grapes. And just like other fruits as they ripen throughout the season, grapes start off more acidic than sweet. In general, acids and sugars develop in inverse proportion to one another, so just as an underripe peach will taste too tart (too much acid and not enough sugar) and an overripe one will be cloyingly sweet (too much sugar and not enough acid), the same goes for wine grapes. Picking decisions at harvest are often based on, among other factors, the balance of acidity and sugar in the fruit.

When it comes to pairing wine and food, acidity plays an important role in offsetting richness. Especially in white wine, acid can perk up otherwise heavy meals. So just like you wouldn't want to pair a glass of whole milk with a bowl of fettuccine alfredo, you also wouldn't choose to pair that particular pasta dish with a rich, oaky, buttery Chardonnay. Instead, you'd find a far better pairing in a wine that's fresher and more mouthwatering. Pinot Grigio, Vernacchia, or even Champagne would be delicious, and cut through the butter, cream, and cheese beautifully. These wines cleanse the palate and get you ready for the next bite.

Acidity in wine can be highlighted by cooler serving temperatures. This is why lighter and more acid-driven wines — like Pinot Noir among reds and Sauvignon Blanc among whites — are best served cooler than their richer, less-mouthwatering counterparts. It's also one of the reasons why people tend to gravitate toward more crisp white wines in the summertime and richer ones in the autumn and winter.

No matter what's in your glass or the foods you'll be pairing your wine with, acidity plays a very important role.