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What are Tannins in Tea, Are Good or Bad?

Apr 20,2024 | TeaTsy Team

Tannins are a class of polyphenol compounds that occur naturally in many plants. It is widely found in a variety of foods and beverages such as wine, chocolate, and tea. 

Teas with a high tannin content have a bitter flavor with a strong astringent taste, especially green and black teas. In this article more information about tannins in tea will be explained, so keep reading.

Related read: What is black tea

tannins in tea

What are Tannins?

Tannins are a broad class of naturally occurring polyphenolic compounds found in a wide variety of plants. Their bitter and astringent flavors help plants survive by reducing their attractiveness to herbivores.

In tea, tannins are responsible for adding depth of flavor and creating a distinctive dryness in the mouth, or what we perceive as a wrinkled feeling in the mouth. In addition to their impact on taste, tannins are also recognized for their antioxidant properties and anti-inflammatory, helping to fight free radicals in the body and support overall health.

Tips: In living organisms, free radicals can destroy cellular structures through oxidative reactions, which can lead to cellular damage or malfunction, inducing diseases such as heart disease and cancer.

Benefits of Tannins in Tea

Tea contains not only caffeine but also tannins. The benefits of these factors contribute to making tea a beverage with health benefits. These tannin benefits in tea include

  • Antioxidant properties: Tannins are potent antioxidants that help neutralize harmful free radicals in the body. This action reduces oxidative stress, which has been linked to several chronic diseases such as heart disease and cancer.
  • Heart Health: Studies have found that tannins promote heart health by lowering blood pressure and improving cholesterol levels. They also enhance blood vessel function and reduce inflammation, all of which are important factors in preventing heart disease.
  • Blood Sugar Control: Some studies have shown that tannins can help control blood sugar levels by affecting glucose absorption and insulin sensitivity. This is especially beneficial for people with diabetes or those at risk.
  • Nervous System Benefits: Research suggests that tannins may have neuroprotective effects that may improve brain function and reduce the risk of neurodegenerative diseases such as Alzheimer's.

Other sources of tannins include:

  • Red wines
  • Coffee
  • Grapes
  • Apple juice
  • Strawberries
  • Pomegranate
  • Olives
  • Chocolate/Cocoa
  • etc.

tannins in tea - green tea

Potential Downsides

While there are various health benefits to having tannins, there are also potential drawbacks:

  • Iron absorption: Tannins bind to iron, especially non-heme iron found in plant foods, making it more difficult for the body to absorb this essential nutrient. This is of particular concern for people with iron deficiency, vegetarians, or vegan diets.
  • Digestive Problems: In some people, especially those with sensitive stomachs, drinking large amounts of tannins can cause gastrointestinal upset or lead to nausea and constipation.
  • According to the National Institutes of Health, tannins or other green tea compounds may increase levels of nadolol, a beta-blocker used to treat high blood pressure and certain heart problems.

What is Tannic Acid in Tea

Tannins are not tannins, they are specific types of tannins. Usually associated with the tanning of leather, it is mainly derived from the bark of oak trees and the skins of certain fruits.

Tannins are not usually found in tea. Instead, tea contains other forms of tannins, such as catechins in green tea and theaflavins in black tea. These tannins give tea a rich variety of flavors - from slightly bitter to refreshingly astringent - without the harshness associated with tannic acid.

How Much Tannin Does Tea Contain?

All teas contain tannins, and the amount varies from one type of tea to another. According to a January 2015 report in the Journal of Chemical and Pharmaceutical Research, black tea has the highest concentration of tannins, ranging from 11.76 to 15.14 percent, while green tea has the lowest tannin content, averaging 2.65 percent (with a high of 3.11 percent). Oolong tea is in the middle of black and green teas with 8.66%. White tea, which is made from young tea leaves and undergoes minimal processing, has the lowest levels.

The most intuitive way to visualize tannin content is to rely on your extremely sensitive taste buds. If you can't detect bitterness and don't have a dry astringent taste in your mouth, this tea drink is relatively low in tannins.

Factors Affecting Tannin Content in Tea

Tea Type and Processing

Different types of tea have varying levels of tannins due to the specific tea plant and the processing methods used. For instance, black tea undergoes full oxidation which increases its tannin content, giving it a darker color and stronger flavor. On the other hand, green tea is less oxidized, resulting in lower tannin levels and a lighter, fresher taste.

Brewing Time

The longer you brew the tea, the more tannins are extracted. A quick steep of two to three minutes might result in a milder flavor with fewer tannins, whereas brewing for five minutes or more can significantly increase the bitterness and astringency due to higher tannin extraction.

Age and Maturity of Tea Leaves

Younger tea leaves, such as those used for premium green teas like Shincha or first flush teas, generally contain higher levels of tannins compared to older, more mature leaves. This is because younger leaves need more protection against insects and hence have higher tannin concentrations.


Tea grown at higher elevations tends to develop more complex flavors, including higher levels of tannins. The cooler climate and greater exposure to ultraviolet light at high altitudes can enhance the concentration of tannins, contributing to a richer flavor profile.

Teaware Materials

Different teaware materials have different tea-drinking experiences and also affect the tannin content to some extent. Generally speaking, pottery and clay materials can reduce the tannin content in tea. Because of its porous nature, it can absorb some of the tannins during the brewing process.

Tea Set


Understanding the positive and negative effects of tannins in tea will help you to be more health-conscious in your regular tea drinking. If you are iron deficient, it is recommended that you do not drink tea. Eating foods rich in vitamin C, such as peppers, potatoes, cantaloupe, or oranges, before or after drinking tea can also neutralize tannins.

If you would like to purchase a quality teaset to reduce the tannins in your tea, feel free to browse Teatsy tea sets to find a teacup that suits your style and style of tea.