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Drinking various types of tea and especially strongly brewed tea with large amounts of tea leaves, boiling water, and long infusions. This experience of a dry feeling mouth is very common.
The cause of dry mouth is intrinsic to tea, which means that every tea has the potential to cause this feeling. Although this is true only for true tea made from Camellia Sinensis.
I want to share how and by what this experience is caused. Further, you will learn how you can influence and avoid this feeling in your tea-drinking experience.
SHORT ANSWER – Why Tea Makes Your Mouth Feel Dry
The feeling of a dry mouth when drinking tea is primarily caused by tannins, which is a class of chemicals contained in tea leaves naturally. The amount of tannins that are extracted from the tea leaves depends on the amount of water, water temperature, steeping time, amount of tea, and leaf grade.
This is a very basic answer. There’s more to learn about tannins and how they cause your mouth to feel dry. Further, if you continue reading, you will learn how you can recognize tannins in your tea and what exactly you can do about that.
About Tannins In Tea And How They Cause A Dry Mouthfeel
Tannins, which are also called tannoids, are a class of chemicals that primarily exist in various plants. Causing the feeling of a dry mouth is, apart from chemical structure, what all tannins have in common.
The tannin that is responsible for your experiences with tea is tannic acid. That’s the main tannin contained in the leaves of the tea plant and the beverage made from them.
Why Are Tannins In The Tea Leaves?
In nature, there’s almost always a good reason for a chemical to exist in any organism. And tannins are very common in the world of plants – so why is that?
According to the U.S. Forest Service, Tannic acid enables the tea plant to protect itself from various bacteria and fungi that would otherwise hinder the plant’s ability to grow or even destroy the tea plant.
What Are Tannins Good For?
Tannins inside the tea leaves, stems, and the bark if tea trees protect the tea plant from bacteria, fungi, and other predators such as smaller insects.
Tannins do so by binding to enzymes and proteins and thus hindering the growth of such microorganisms. Further, this characteristic prevents larger predators from eating the leaves or stems of the tea plant.
How Do Tannins Cause The Feeling Of A Dry Mouth?
There are at least two aspects of the dry mouthfeel that are independently caused by the tannic acid in your tea.
Tannic acid and other tannins react with both proteins and enzymes and do so in your mouth, too. The reaction between the tannic acid and the proteins in your saliva is part of the astringent feeling you get.
The tannins in your tea additionally cause the tissue inside your mouth to contract. This enhances the effect and together these reactions produce the mouthfeel you have experienced.
What Is Astringency?
The dry mouthfeel that you are experiencing is called astringency. The tannic acid in the tea leaves reacts with your saliva and causes the tissue to contract. This results in a dry and sometimes unpleasant feeling.
What Influences The Amount Of Tannins And Dry Mouth
No matter which type of tea you buy, there will always be tannins contained in the tea leaves (and stems). This is not changed much during production.
Oxidation and post-fermentation of tea leaves do not remove tannins from the tea. What does help against tannins is roasting the tea leaves thoroughly.
A perfect example of such a well roasted tea is the Wuyi Cassia Chinese Oolong sold by Harney & Sons. It’s a fair price for Wuyi cliff Tea.
According to a publication in Food Chemistry, Tannic acid decomposes above 400 °F (200 °C), though. Because of this, roasting is a viable method to destroy the tannins.
Other than this form of processing, there’s a lot you can do while brewing your tea to prevent the dry mouthfeel.
Amount Of Water And Water Temperature
Tannins are very soluble in water and tannic acid is not an exception to that rule. This limits the influence of water temperature on the extraction of tannic acid from the tea leaves.
Many other compounds found in tea are much more soluble in hot or boiling water than they are in cold water, but the solubility of tannins is too high for this to be a viable solution.
You can use the high solubility of tannic acid in water to your advantage, though. Using cold water, you can wash out most of the tannic acid from the tea leaves with a semi-quick rinse.
Other compounds that are less soluble but more important for the taste of your tea will remain inside the tea leaves. After the rinse, you will have a tea that is much less likely to cause a dry mouthfeel.
Why Water Temperature Is Not Important
The tannic acid contained in the tea leaves is very soluble in both hot and cold water. Lowering the temperature will not prevent tannins to be dissolved and thus not prevent a dry mouthfeel.
Influence Of Steeping Time And Stirring
The amount of tannic acid that is extracted from the tea leaves increases with longer steeping times. Stirring or moving the brewing vessel will increase the extraction rate.
This is because tannins that are in the middle of the tea leaf take longer to reach the water than those which are close to the leaf’s surface.
Because of this, you will not be able to wash out the tannins completely with a rinse. Some amount of tannic acid will remain inside the leaves but can get to an unnoticeable level.
Choose The Right Amount Of Tea Leaves
More important than the amount of tannic acid you are drinking, is the concentration of tannins in the resulting brew. I’ve made awful experiences with concentrated solutions of tannic acid during my studies.
If you have a tea that tends to cause a dry mouthfeel, the amount of tea you use may be too high. Tannins are less dominant with lower leaf-to-water ratios.
The concentration of tannins just about doubles if you double the amount of tea for a given volume of water. I’d recommend trying the same tea with fewer tea leaves or more water.
How To Spot Tannins In Your Tea
Tannic acid has a characteristic brown color and can easily be spotted in the tea you make. Not every tea that is brown contains tannins, but a very light colored tea can’t contain much of it.
Leaf Grade And Surface Area
One more thing that you may want to take into consideration is the leaf grade. The main grades commonly found are dust, fannings, broken leaf, and whole leaf.
Tannic acid is distributed inside the tea leaf and is much easier to extract from fannings or dust than from whole leaf tea.
On more technical terms, the increased surface area and small particle size allow for all of the tannins to be extracted, quickly. That’s not the case for whole leaf tea.
On the other hand, whole leaf tea will allow more tannins to be released into the second, third, and later infusions. Far less noticeable, though.
How To Make Tea That Does Not Make The Mouth Dry
To summarize this article, I want to give you a concise list of things that you can do to increase or decrease the dry mouthfeel and what doesn’t have an influence.
Adjust The Leaf-To-Water Ratio
The high concentration of tannic acid in your tea is responsible for the dry mouth sensation. Lower concentrations will lessen this effect.
Decreasing the leaf-to-water ratio will result in a tea with such a lower concentration of tannic acid. Extending the time you infuse your tea allows for sufficient flavor while avoiding a dry mouthfeel.
Use High-Quality Tea Leaves
The extraction of tannins from the tea leaves is faster with broken tea leaves and much faster even with fannings and dust. If you choose whole leaf tea, tannins won’t extract as quickly.
Because of this, the dry mouthfeel is much lighter in the first infusion with whole leaf tea. It will not completely disappear with the second or third infusion, though.
Rinse The Tea Leaves With Cold Water
Tannic acid is very soluble in water, no matter if it is cold or boiling water. Therefore, the tannic acid can be extracted in a semi-quick cold water rinse and be discarded.
How To Avoid Tannins In Your Tea
Soak your tea leaves in cold water for a few minutes and discard the water before brewing. This way, much of the tannins will be lost and can not cause your mouth to feel dry.
Many other compounds in tea are less soluble in water and will remain in the tea leaves until a proper infusion with hot or boiling water is done. You will not lose much of the flavor of you tea.
If you want to learn more about tea, I highly recommend you the book Tea: History, Terroirs, Varieties. It covers all the basics and doesn’t cost much. You can check the price on amazon here.