Understanding the components and chemicals found in wine is essential to understanding wine, whether tasting, creating, or critiquing. After all, if you don’t understand where the qualities of a wine come from it is difficult to judge what a wine is or is not doing right and two of the hardest aspects for beginners to distinguish in any wine are acidity and tannins.
Both compounds play a key role in the taste and texture of wine each having a different effect on the drink. This of course raises the question: what is the difference between acidity and tannin in wine?
Acidity determines how a bright a wine feels in the mouth while tannins determine how full it feels and how well it ages with both compounds having more effects on wine than simply this.
What do Acidity and Tannins do in Wine?
To understand the difference between acidity and tannins, you must first understand what each compound does in the wine making process.
The primary purpose of acidity in wine is to enhance the texture of the wine, sharpening and brightening how it feels on the mouth and tongue. The more acidity in a wine the lighter and more refreshing it feels, while less acidic wines are heavier with a fuller body.
This is because the forms of natural acid found in wine do not dissolve in alcohol, so they help to balance the qualities of the drink. If there is too little or too much acid in the wine after production it can ruin the taste and feeling of the wine.
Without acid wine can be almost sickeningly sweet with a sticky texture, if it remains drinkable at all. Of course, too much acid can create a weightless, yet sharply tart flavor that is just as unappetizing.
In contrast to acidity, tannins are considered a metric for how well a wine can age, as well as having many more effects on the quality of wine. One of the most important effects tannin has is giving wine many of its health benefits, including antioxidant effects which can lower your risk for heart disease.
Tannin is naturally found in grapes as well as oak wood, which is sometimes used to store wine for aging. This is why gauging the levels of tannin or the strength of its effects in a wine can help determine how well it can age.
Tannins are also needed to balance the qualities of wine by providing bitterness and drying out the mouth somewhat. Without these effects a wine’s taste and texture can be thrown out of balance. Imagine having a biscotti and a good cup of coffee or an over steeped tea with a splash of milk. Acidity keeps wine youthful and bright, while tannin provides weight and longevity.
Thus, acidity effects the texture of wine in the mouth while tannins can be used to measure the potential age of a wine and balance its flavors. This is the primary difference between acidity and tannins in wine.
Where do Acidity and Tannins Come From?
There are more differences between acidity and tannins in wine than how they help the fermenting process. Both factors are natural in the wine making process but come from radically different sources.
Acid in wine is the result of the natural acidity in grapes, which is lowered over time by absorbing potassium from the surrounding soil. Unripe grapes have a more acidic taste than ripe grapes, and apply the same effect when used in wine.
The two primary forms of acid found in grapes, malic and citric, do not dissolve in alcohol so they linger in the wine through the fermentation process. These two forms of acid contribute to the tart taste of more acidic wine, and they are the same natural acids that give certain fruit their sour flavor.
There is another type of acid found in wine which does not come from grapes, lactic acid. Lactic acid comes directly from the fermentation process itself, and is what helps give wine a lighter, smoother feeling in the mouth. Lactic acid is formed when the bacteria Lactobacillus converts Malic acid into lactic acid (the acid present in milk and and yogurt, and not to be confused with lactose)
In contrast to acidity, tannins are simply a polyphenol in a wine that tastes bitter and dries out the mouth that serve as an antioxidant and natural preservative. Both tannins and polyphenols are completely natural in many different plants besides grapes.
Tannins are found primarily in the stems, skins, and seeds of grapes, which are often left in must (the fermenting grape juice and skins etc.) as it ferments. As previously stated, tannins can also be found in oak wood, which is commonly used to make barrels. This is why red wines are more tannic than white wines, since they have more contact with the stem, skins, and seeds of grapes.
As an interesting fun fact, tannins can also be found in a wide range of plants besides grapes, including coffee beans, cocoa beans, and tea leaves.
The greatest impact on the source of acid comes from the winemakers picking choice. Acid is converted into sugar during the ripening process, while tannin increases in skins and seeds as berries get older on the vine. The choice to pick fruit comes when a winemaker feels that the balance between acid and tannin is aligned.
What Do Acidity and Tannins Taste Like in Wine?
The last key difference between acidity and tannin in wine, although certainly not the least, is how they influence the taste and texture of the wine. Just as they effect the qualities of the wine in different ways, acidity and tannin have different effects on a wine’s flavor.
Acidity creates a tart, sour flavor with a light and bubbly mouth texture, often accompanied by a feeling of wetness in the mouth. This is because most of the acids found in wine are the same as those found fruit like apples or lemons, which cause you to salivate.
If a particular wine leaves you with sour aftertaste and a tingling in your mouth sensation, it is high in acidity.
Tannin, unlike acidity, create a bitter taste in wine while making the mouth feel dry, primarily because tannins dry out saliva on the tongue. Some have also described tannins as having a particulary astringent flavor to them.
Wines high in tannins have will have a bitter aftertaste and leave your mouth, especially your tongue, feeling dry. Wines lower in tannins will have a less bitter aftertaste and a moist texture in the mouth after drinking.
As a side note, it is important to remember that tannins and dryness in wine are two different concepts. Dryness is determined by the sugar content of the wine, specifically how low it is, while tannins simply create a dry after effect in the mouth when consumed. One is not a metric or indicator of the other, they are separate metrics.
The differences between acidity and tannin in wine are numerous, as each chemical takes the taste and texture of the wine in a new direction. Acidity is key to a wet after effect and a sour taste, while the bitterness and drying effect of tannins show how well aged and balanced a wine is.