Where do the tannins in the grapes come from

Many people will say that drinking wine always has a "astringent" feeling. Where does this "astringency" come from? Is it good or bad? This has to start with the tannins in the wine. In this issue, we will answer what is tannin.

Tannins belong to the polyphenols and are widely distributed compounds that are found in many plants. Tannins are known to produce a dry mouthfeel. Tannins are commonly found in grape skins, stems and seeds.

Among them, the most important ** is the grape skin, and the tannins are mainly found in cells that are relatively tough with the grape skin.

If the skins are treated in a rough or over-pressed manner, many of the tannin-containing cells will burst and release more tannins. Tannins are bitter and astringent compounds that are abundant in nature. They are found in the wood, bark, leaves, and fruits of plants such as oak, rhubarb, tea, walnuts, cranberries, cocoa, and grapes.

The presence of tannins makes the plant unpalatable. Their purpose in nature is to stop animals from eating the fruits or seeds of plants before they reach maturity. Although the tannins have a bitter taste, when handled properly, they become delicious!

It includes tea, coffee, dark chocolate and of course, wine. The tannins in grapes are mainly found in the skins, seeds and stems of grapes, as well as in the barrels used in the aging process. They provide texture and mouthfeel, as well as weight and structure to the wine.

The tannins in the wine depend on how long the grape juice has been with the skins and seeds, so the winemaker will ferment the skins and seeds together with the juice, so that not only can you get more beautiful color from the skins, but also get more tannins. This explains why red wine has stronger tannins than white wine. At the same time, oak barrels can also bring a portion of the tannins to the wine, increasing the complexity and ageing capacity of the wine.

The fruit stalk is rich in tannins, so the contact of the stalk with the must during the maceration phase results in the must being rich in tannins.

In addition, if the skins and juice are already full of tannins, full or partial destemming is performed. The seeds also contain tannins, which account for 20%-55% of the total phenolic content in the grape berries, so the ripeness of the fruit is very important. As the temperature increases and the ripeness increases, the chemical composition of the polyphenols in the grape skins changes, resulting in softer bitter and green tannins in the immature grapes, a phenomenon that greatly affects the tasting characteristics of red wines in different climates.

Wines from cooler regions, such as the Loire Valley and Bordeaux, have a typical hard tannin taste, while wines from hotter regions, such as Australia and California, have milder and ripe tannins.

Tannins are one of the two phenolic compounds found in wine.

1. Tannin production.

1) When the grapes themselves (seeds, skins, and stems) and red grape juice are soaked and fermented with skins and seeds, the pie will be extracted into the wine through alcohol.

2) In oak barrels, when the wine is matured in the barrel, it will touch the inner wall of the barrel and extract the tannins in the oak.

Second, the role of tannins.

1. Tannins determine the flavor, structure and texture of the wine.

The structure of wine is made up of tannins, wine dust, acids and other factors. These factors determine the texture of the wine, red wines lacking tannins will be unbalanced in structure, light texture, no thick feeling, in addition to tannins also determine the flavor of the wine, by the tannins, pigments and yeast dead cells combined into the sediment in the wine biochemical changes over a long period of time, to develop the mellow and delicate flavor of the old wine.

2. Tannins support the long-term maturation of red wines.

The antioxidant properties of tannins allow tannin-rich red wines to mature for many years, while thin wines without tannin support will oxidize and turn sour after two to three months, even if the bottle is not opened.

3. Tannins are beneficial to the prevention of cardiovascular diseases.

Tannins contain a substance called procyanidols, which not only has a protective effect on human blood vessels, but also protects arterial canals and prevents arteriosclerosis, in addition, procyanidols can also control cholesterol and inhibit the oxidation of low-density cholesterol in the blood.

It is an organic substance with the chemical formula C76H52O46 and is a type of tannin obtained from gallnut。yellow or light brown light amorphous powder or scales; It is odorless, slightly peculiar and extremely astringent. Soluble in water and ethanol, soluble in glycerol, almost insoluble in ether, chloroform or benzene.

Its aqueous solution and iron salt solution meet to become blue-black, and sodium sulfite can delay the discoloration. Industrially, tannic acid is widely used in tanning and in the manufacture of blue ink. Tannic acid coagulates the protein trace.

People chemically treat pig skins and raw cowhides with tannic acid, which can coagulate the soluble proteins in the hides. As a result, the rawhide, which would have been left to stink and rot for a few days, has become a beautiful, long-lasting leather. This tanning process is called leather tanning.

Industrially, tannic acid is widely used in tanning and in the manufacture of blue ink. Tannic acid coagulates proteins. People chemically treat pig skins and raw cowhides with tannic acid, which can coagulate the soluble proteins in the hides.

As a result, the rawhide, which would have been left to stink and rot for a few days, has become a beautiful, clean, flexible, and durable leather. This tanning process is called leather tanning.

Use. 1. It can be used as a food antioxidant. It is generally mixed with vitamin E, vitamin C, or gallic acid.

2. Tannins are used as viscosity reducers and filtration loss reducers for water-based drilling fluids, which can improve the quality of filter cakes. It is also used to tann hides and hides to convert them into leather. Tannins have the activity of reacting with proteins, polysaccharides, alkaloids, microorganisms, enzymes, and metal ions, and have the characteristics of antioxidant, free radical capture, antibacterial, and derivatization reactions.

It is more and more widely used in food processing, fruit and vegetable processing, storage, cosmetics, medicine and water treatment.

3. Because tannic acid can be combined with protein to form water-insoluble tannic acid protein, it can be added to the shampoo to prevent the dissolution of hair fiber protein and protect hair, and the use in nail products can increase nail strength. Gallic tannin and isogallic tannin have a strong free radical scavenging effect, and the effect is similar to gallic acid and catechins, and can be used in skin care products to protect the sun and brighten the skin. Tannic acid has astringent and antibacterial properties, and is clinically used for local bleeding, toothpaste for tooth protection and prevention of gum bleeding.

4. Mainly used in medicine, ink, printing and dyeing, leather and metallurgy and other industries as well as water treatment, tannins have flocculation, deoxygenation, scale inhibition and sterilization in the water treatment process.

Because there are a large number of hydroxyl groups and carboxyl groups produced after partial hydrolysis in the molecular structure, it forms a complex with calcium and magnesium ions in the water, which prevents the formation of scale by calcium and magnesium ions in the boiler water, and can also reduce the deposition of calcium sulfate in the cooling water and play a dispersing role. In addition, the cohesion of the tannins collects the sediment into slag, which is discharged into the boiler and cooling water system through the blowdown.

5. It can be used as a fining agent for low-alcohol wine and fruit wine. It can also be used as a leather tanning preparation.

6. Tannic acid is used for chrome-free passivation of galvanized layer.

Tannins in wine are a common polyphenolic compound, which is commonly found in plant skins, leaves and unripe fruits, and when tasting wine, you can feel the dryness of the tannins in the wine and the subtle bitterness of the wine.

Wine is a fruit wine made from grapes as raw materials in the town of Nagau. Red wine is made by fermenting grapes with red skins and white flesh or red flesh mixed with grape skins and juice. Wine that does not contain self-fermentation or artificially added CO2 is called still wine, that is, still wine.

Tannins are one of the two phenolic compounds found in wine, especially in red wines. The tannins in wine are generally fermented by maceration of grape seeds, skins and stems, or by oak barrels where red wine is stored. The amount of tannins can determine the taste of the wine.

Wines with rich tannins can be stored for several years and gradually develop a mellow aging flavor. Red wines lacking tannins have a lighter texture. Tannins can cause the mouth to feel dry and wrinkled in the oral mucosa after the wine is ingested.

Wine Profile

Wine is a type of fruit wine made from grapes. Its alcohol content is higher than that of beer and lower than that of liquor. Ancient Persia was one of the cradles of ancient civilizations.

Most historians agree that Persia may have been the first country in the world to make wine. Nutritious, some believe that wine is one of the healthiest and most hygienic beverages.