What are tannins in beer mainly responsible for?

Tannins in beer are primarily responsible for contributing to astringency. Astringency is a tactile sensation experienced in the mouth, often described as drying or puckering. This sensation is similar to what is found in red wines, where tannins derived from grape skins, seeds, and stems create a mouthfeel that can be both complex and sometimes overwhelming if present in high amounts.

In the brewing context, tannins are most commonly extracted from grains, particularly the husk during the mashing process, and can also come from oak barrels used for aging certain styles of beer. When extracted, they can interact with proteins in the beer, leading to the sensation of astringency, which can influence a beer's overall balance, mouthfeel, and drinkability.

Understanding the role of tannins helps brewers manage the fermentation and aging processes, as well as balance the sweetness and bitterness imparted by hops and malt, creating a more harmonious product. This sensory characteristic is an important aspect of developing beer styles that require a certain level of complexity and depth.