Salty, sour, sweet, and bitter, these are the four main tastes that we pick up in our taste buds. Other than these four tastes, everything we taste in wine is from our noses. 

Bitter flavors are generated in the back of our tongues. This flavor is caused by several compounds, including tannins that are produced in the seeds, skins, and stems of the wine.

Some winemakers prefer to add bitterness to their wines, while others avoid it. Too much bitter in wine will throw its balance off. This can be considered a defect in the wine if it’s overdone.