The term tannins is derived from the French term tanin and they can be found in nature in various trees and shrubs as: pods, tea, cocoa, nuts and grapes but they are also extracted from the barrels that red wine is aged in. Tannins are naturally antioxidants found in all products tied to grapes because grapes are loaded with polyphenols and add both bitterness and astringency to the wines.
The tannins act as a preservative, they contribute directly to the ageing of wine and protect the wine from oxidation, so a wine that contains a small amount of tannins can taste flat. Red wines tend to have higher tannins than whites because white wines are fermented after the juice is pressed from the grapes and the skins has been removed. If the grapes are ripe late, the tannins are softer, resulting in wines that can also be enjoyed very young. If the grapes are harvested early the tannins in the wine taste dry.
On the palate tannins creates a furry taste. As the tannins interact with proteins present in the saliva they make the tissue to contract which will lead to salivation. In addition, one has the impression that the mouth would have a contraction. This is due to the astringent effects of tannic acid and the sensation is caused by a chemical compound that makes body tissue and blood vessels contract.
Wines with a particularly high content of tannin are, for example, almost all Bordeaux wines as well as wines from the grape varieties: Cabernet Sauvignon, Malbec, Nebbiolo, Sangiovese, Syrah. Tannat, Tempranillo etc. Grape varieties and wines with a low tannin content are Barbera, Merlot, Cannonau etc
Before listing the possible side effects of tannins there are good news for all wine lovers: tannins can have a lot of positive properties on the organism. The antioxidant action helps to treat diarrhea, improve cardiovascular health and immunity and is harmless in small doses . But when the taste is rough, they can lead to constipation and hinder the digestion of proteins, fiber, minerals and carbohydrates. Tannin sensitivities can go from a headache to full-blown respiratory distress so consider an allergy test if your response is severe. If you are already diagnosed with tannins intolerance but you don’t want to keep the bottles in a wine cellar you can switch to white wines or Pinot Noir.