Wine tannins are chemical compounds that naturally occur in parts of a grape and that are found in oak barrels. These chemicals contribute to a wine's structure, taste, and ability to age without spoiling. When there are a lot of tannins in a wine and that beverage has not been allowed to age, it will likely have a bitter taste. It is believed that these chemicals may be the cause of the headaches that some people experience after drinking wine, but they also help an individual by acting as antioxidants.
Tannins serve as a natural defense mechanism by helping to protect plants from wild creatures. These chemicals do this by producing a bitter taste that make a plant undesirable. Found in several parts of a grape, including the skins, seeds, and stems, tannins are also located in tree bark. As a result, they are present in the oak barrels that wine is stored in.
The production and storage process affects the amount of wine tannins in a beverage. There are generally more wine tannins in beverages made from red grapes than there are in the wines made from white grapes. This is due to several differences in the production process. For example, red grapes tend to be crushed more aggressively, which results in the transfer of more tannins from parts such as the skin to the wine that is being made. As red wines are commonly aged for longer periods than white wines, more tannins seep from the barrels into red wine.
When there are few tannins, individuals are usually discouraged from keeping the wine for extended periods. If wine has a significant amount of tannins, it may taste bitter or appear astringent. This type of wine is commonly described as tannic, and it can usually be kept for long periods. Allowing tannic wine to age can change its taste because, as time passes, the wine tannins tend to calm and the potency of their bitterness subsides. As these chemicals are natural preservatives, they help prevent the wine from spoiling during this time.
It is the tannins in the wine that are often blamed for the headaches that some people experience after consuming these beverages. The relationship between tannins and starches is believed to have adverse effects on serotonin, resulting in a headache. On the contrary, tannins are also believed to have some health benefits associated with being antioxidants.