Skip to content Skip to footer

Understanding Wine Tannins


There are many traits to wine that give each a unique flavor. Wine Tannins are a trait that introduce a bitter or astringent taste, which is particularly noticeable in red wines. The original use of “tanning” was in regards to curing leather in order to make it soft, firm and rigid. This was used when making leather shoes, belts, bags, and the like.

In 2013 Liquor Mart published the following on wine tannins:

Tannins As A Natural Defense Mechanism

Tannic grapes lead to tannic wine

“It is believed that Tannins in nature is one way a plant can defend itself against hungry and marauding animals. The bitter and astringent taste makes eating the plant either unpleasant, or at times, even indigestible. This prevents herbivores from consuming the plant whole, thus increasing the likelihood of the plant surviving.

The sharp and bitter taste that arises from tannins is created from astringent principles and compounds found in many forms of vegetation. Mainly, those compounds are complex glucosides of catechol and pyrogallol. Tannins are found principally in the bark, immature fruit, and leaves of a wide array of plants.

However, for the grapes we use in winemaking, the grape vine itself uses Tannins in a very unique and special way. Grapes as they’re forming, start out small and extremely astringent. The tannins found within are highly acidic and also cause the grapes to remain a vibrant green. Through no coincidence, the color of the grape is also the same color of the plant. Thus, effectively camouflaging the fruit from potential animals looking for food.

The reason for this is that the grapes sole purpose for the plant is to carry its seed, which it doesn’t want to be taken away prematurely. The camouflaging color of the grape as well as the bitterness created from the Tannins, in essence, ensures the grape will not be eaten before it has had a chance to ripen. Once ripened, the grape changes color so as to stand out more, its acidity decreases through the softening of the Tannins, while the sugar content of the grape increases making the grape overall much more attractive to animals. An animal then eats the ripened grape, moves on, the grape is digested and the seeds are passed through the animal into a new location. This is the natural cycle for a grape; it is solely a transportation mechanism for the seeds of the plant.

Types Of Tannins In Wine

The Tannins we notice in wine mostly come from the grape skins, stems, and seeds. The amount of Tannins allowed in a wine is dependent upon the particular wine making process. Additionally, Tannins can find their way into a wine from the barrels used for aging. More specifically, from new barrels where the wood used is still relatively fresh.

In sum, there are mainly two different classes of Tannins found in wine: condensed and hydrolysable. Hydrolysable Tannins are those found not in the grape, but in the wooden aging barrels. They are considered less important when making wine, as they are less noticeable, but an experienced wine producer will certainly keep them in mind. Condensed Tannins are mostly what wine producers are concerned over, and are Tannins found within the grapes.

Tannins Affect On Mouthfeel and Astringency

Tannins contribute in two major ways to the characteristics of a wine, and can
easily be confused by those who taste it. Wine astringency and bitterness are often, in error, used interchangeably as they are in fact not the same.

Perceiving bitterness is one of our five primary taste sensations with specific receptors for bitterness being found in our taste buds. Perceiving astringency is not a taste, rather, it is only noticed through our sense of touch. Tannins astringency is noticeable because the Tannins bind with salivary proline-rich proteins and precipitate them out. This results in a distinctive feeling of friction, dryness, or roughness in the mouth when drinking wine.

This is the reason the term “mouthfeel” had been created, and was meant to describe this exact sensation wine creates. As such, wine mouthfeel is an extremely important property of any wine, and though it is often confused with bitterness, it is still greatly appreciated.

Quite literally, without the presence of Tannins in a wine, you would have a markedly different beverage. The same logic also holds true for the total number of Tannins found. The management of tannins in the winemaking process plays a significant and major role in the resulting quality of a wine and is one that winemakers certainly don’t overlook or take lightly. Balancing the astringency and bitterness of a wine, along with all other potential characteristics, is what turns your everyday table wine into fine wine worth savoring.”



(Posted in Simply Served Wine Wisdom, By Alisa Customer Paradigm)