Grape Acidity

Wine acidity refers to the natural malic and tartaric acids found in grape pulps. When you think of acid, think about that acidic taste found in lemons, limes and grapefruit. Acid is what makes both fruits and wines refreshing. Sometimes these harsh acids are transformed into lactic acid later in the winery to achieve a softer, creamier taste. However, acid plays an extremely important role in a wine’s final taste.

Some wines are naturally more acidic than others. For example, Sauvignon Blanc and Pinot Noir grapes will be more acidic than Viognier and Pinotage. Grapes used for Champagne or Sparkling wine will have an extremely high acidic level to tolerate the autolytic processes and remain balanced. Here are a few other examples:

Acidity & Climate

In most cases, grapes grow between 30° and 50° latitude. This covers much of Europe and the U.S., as well as the southern tips of South America, Africa and Australia. There are a lot of climate variations within those grape-growing boundaries. In the Northern Hemisphere, climates will be cooler north and warmer south. On the contrary, the southern hemisphere will experience cooler climates the further south you go.

Sun and heat are essential to ripen grapes. The more sun and heat the vines receive, the riper the grapes become. Generally speaking, grapes grown in cooler climates will have higher acidity levels because the grapes lack the intense sun and heat needed to produce the high sugar levels found in warmer climates. For example, a cool-climate Pinot Noir in northern Oregon will taste more acidic than a Pinot Noir that baked in the hot sun of California’s Central Valley.

Acidity & Growing Season

When grape berries form on the vines and begin to produce pulp juice, they have high levels of acidity. As grapes ripen during the course of the growing season, a process known as Veraison, the acidity levels fall and the sugars levels begin to rise. If you were to pick a grape in July and eat it, the tart acids would be very strong and off-putting. However, a grape from that same bunch in October would have less acid and and more sugar. Some grapes, like Riesling, are able to retain their acidity throughout the growing season, giving grape-growers a wider harvest window and more options for different wine styles.

Using specialized instruments and often their own intuition, grape-growers must determine the absolute best time to harvest the berries with their ideal balance of acidity and sugar. For some grapes, the acid decreases so quickly the grape-growers must hurry and pick before it’s too late. Over-ripe grapes will have very little acid, and won’t taste very refreshing. In these cases, they may have to be later blended with more acidic wine for a balanced taste. In other cases, grapes are purposely left on the vine to produce sweet wine styles with lower acidity.

Acidity in the Winery

Once grapes arrive in the winery, a wine-maker will have to work with the grapes’ acidity and sugar levels in order to create the final style of wine they want. In some warmer regions, wine-makers are permitted to add acid to their wine to make it more balanced. This practice, known as acidification, is outlawed in many wine-growing regions.

It All Comes Down to the Final Taste!

Similar to how lemonade works, wine needs have the right amount of acid in order to feel balanced and refreshing! Wines with too much acidity will taste tart or sour. Wines with too little acidity will taste flabby. Wine-makers must find the perfect balance so that we enjoy the final product.

Acidity cannot be detected by smell. We must taste the wine in our mouth in order to gauge its acidity level. The taste buds in our mouth responsible for detecting acidity are found on the sides of our tongue. A wine with higher levels of acidity will cause that acidic taste to linger on our tongue much longer than one that has little acid.

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Unpolished Grape Guides

Wine Aromas & Flavors
Wine Color
Wine Acidity
Wine Sugar & Alcohol
Wine Tannins
Wine & Food

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