What is a Wine’s Tannin and How Can You Recognize It?

Have you ever felt that dry, dry saliva after eating a raw artichoke, unripe fruit, or wild plums? If, after a sip of wine, you experience that same nagging sensation, you can undoubtedly trace it back to the presence of tannin in the wine. But do you know exactly what tannin means? Today we'll explain everything about tannins: what they are, their function in wine, and how to recognize them.

What Are Tannins?

Tannins are natural substances belonging to the polyphenol family, found in the skin, seeds (called grape seeds), and stems of grapes. They have no odor, but they are slightly bitter in taste and give off that typical dry sensation in the mouth, causing a slight contraction of the gums. If tannins are young, they can be more aggressive and tacky, but over time they "soften": during the aging of the wine, in fact, the tannins bind together (a process called polymerization) and lose some of their astringency and bitterness.

How And When Tannins Enter Wine

Tannins, present in the skin, seeds, and stems of grapes, come into play during winemaking, the process that transforms grapes into wine. More specifically, during the maceration and maturation phases of the wine. Their quantity and their role in defining the wine's profile depend on the choices the winemaker makes in the cellar.

The Maceration Phase

After harvesting the grapes, the winemaker must select which solids will be in contact with the must during the maceration phase, favoring the extraction of substances, including tannins. Typically, after selecting the grapes, the winemaker proceeds with the destemming and crushing process: through this process, he separates the stems from the berries and proceeds to crushing them. By crushing the berries, the winemaker obtains the must: the grape juice that will become wine through the fermentation process.

At this point, the must undergoes the maceration phase, during which it remains in contact with the skins and seeds for a variable period of time, depending on the type of wine desired. It is precisely thanks to this contact that the extraction of colors, aromas, and tannins occurs.

More rarely, if the stems are particularly ripe, the winemaker may choose to include them in the maceration: in this case the must will see a greater extraction of tannins.

The Maturation Phase

In addition to maceration, tannin levels in wines can also be increased during maturation. Maturation is the phase following fermentation: after a tumultuous period of great change, the wine needs to stabilize. To achieve this new balance, the wine ages in containers made of various materials: steel, concrete, and wood, to name the most common.

When aged in wood, the barrels the wine is in contact with release additional tannins, contributing to the wine's aromatic and flavorful complexity. The quantity and type of tannins released depend on several factors, including the type of wood used, its size, the degree of toasting, and the age of the barrel.

What Are Tannins For and How Do They Characterize Wine?

Tannins characterize the wine at a gustatory and structural level:

1. They impart astringency: on the palate, tannins bind to proteins in saliva, generating a sensation of dryness and roughness, known as astringency; over time, this characteristic fades and mellows.
2. They influence the structure: Tannins contribute to the structure and body of the wine, giving it greater importance.
3. They aid in preservation: thanks to their antioxidant power, tannins contribute to the longevity of wine, promoting its evolution over time.

What Are The Most Tannic Wines?

We can generally say that red wines are more tannic than white wines, for two main reasons:

1. red grapes contain more tannins than white grapes
2. the production of white wines does not include the maceration phase: the must is not in contact with the skins and grape seeds, therefore the extraction of tannins is minimal

Among the most tannic American wines are Napa Valley Cabernet Sauvignon, known for its firm structure, dark fruit, and powerful aging potential; California Petite Sirah, one of the most deeply colored and tannic reds produced in the U.S.; and Washington State Syrah, especially from regions like Walla Walla, where the wines can be bold, savory, and muscular. Also worth mentioning are some mountain-grown California Cabernet Sauvignons from areas such as Howell Mountain or the Santa Cruz Mountains, which often show especially intense tannins and require time in the bottle before reaching their best balance.