Acids are one of four fundamental components of wine. Its counterparts are alcohol, sugar, and tannin. In tandem with tannin, acidity serves as the backbone of wine providing, structure and longevity.
Three naturally occurring acids in wine are tartaric, malic, and citric. Each derives from the grapes themselves and plays a vital role in the wine production process and final texture and flavor profile of a wine.
Malic acid contributes to wine aromas but is more known for its role in malolactic fermentation. In this winemaking process, the harsher malic acid converts to the softer lactic acid.
Tartaric acid plays a prominent role in maintaining the chemical stability of the wine and influencing the color and taste.
Generally, acidity lends tartness to a wine. When looking at the pH spectrum, all wines lie on the acidic side and range from about 3 to 4.5. For comparison, lemonade is 2.6, and water (neutral) is 7.
The Importance of Climate and Acidity
During the growing season, when grapes are still green, they have very high acidity. As red wine grapes go through veraison, the acidity tamps down, increasing sugar levels. Winemakers strive to pick when the grapes reach a perfect balance of sugar, acid, and ripeness.
Acidity is an excellent example of a fundamental trait in wine with external influences from terroir and climate. For instance, cool-climate regions in Northern France, Austria, and Germany have lower nighttime temperatures and often shorter growing seasons. As a result, these cooler regions produce wines with naturally higher acidity.
Riesling from the Mosel region and brut style Champagne are classic examples of light-bodied, highly acidic wines from cool climates. It’s not just white wines, either. Light-bodied red varieties such as Pinot Noir from Oregon and Gamay, in addition to medium-bodied Grenache, all have lively acidity.
How to Recognize Acidity in Wine
Think back to a warm summer day from your childhood when you were parched and reaching for a glass of lemonade. Did your mouth start to salivate as soon as you read the word lemonade? The same thing happens when sipping a wine that is high in acidity. The mouthwatering sensation that comes from acidity is a clue for sommeliers when blind tasting. The mouth’s natural reaction to acidity provides insights into both the growing region and varietal.
Descriptors like bright, crisp, or zesty are common when describing high acidity wines. Usually, these wines have a light body and tart on the palate. They also sometimes have a slightly spritzy or tingly sensation on the tongue. By contrast, wines with lower acidity have a rich, creamy, and round texture on the palate.
One unique trait of high acidity wines is their ability to pair well with a variety of foods. While a traditional pairing like red Burgundy and mushroom risotto may come to mind first, these wines are perfect for pairing with the unexpected. For example, Champagne with a cheeseburger and fries creates an exquisite harmony of acids, fats, and saltiness.
The Balance of Acid and Sugar
Mary Poppins opined, “a spoonful of sugar helps the medicine go down.” The same concept applies to wine, as sweetness lessens the sensation of acidity. Think of Sauternes, a wine that tastes sweet rather than tart and can age for decades, all because of its high acid structure.
In this episode of Sommelier’s Notebook: An Intro to Acidity on SOMM TV, Claire Coppi, Sabato Sagaria, and Laura Fiorvanti explain the concept further.
Acidity’s Role in Champagne
A less overt example is Champagne which can range from brut to demi-sec depending on how much sugar is in the dosage. Grapes for Champagne and sparkling wines are harvested slightly underripe while acidity levels are still high. The historical importance of acid may be partly because adding sugar is legal in Champagne, but acid addition is not.
Champagne is made via the traditional method, whereas the first fermentation produces a highly acidic base blend used to build the cuvée. The cuvée blend then goes into bottles with yeast and a small amount of sugar to undergo a second fermentation and age on the lees. This aging process ranges from 15 months to 3 years, followed by riddling and disgorgement depending on the vintage. During the disgorging, the dosage or liqueur d’expédition (a sugar mixture) is added to balance the acidity.