What Are Tannins? And Are They in My Earl Grey Tea?

We’ve all heard of bergamot in Earl Grey tea. But what about tannins?

Black tea is full of them. And it’s what gives your cuppa that bitter taste and dark colour. 

But what exactly are tannins? Do they have a purpose? And are they good or bad for you?

From the health benefits to the side effects, here’s everything you need to know.

tannins in earl grey tea

Table of Contents

What Are Tannins?

Tannins are a group of organic and astringent phenolic compounds called Polyphenols.

A natural insect repellent in plants, tannins prevent pests from eating them.  

And you’ll find tannins in both edible and inedible plants. 

For example fruits, vegetables, nuts, seeds, spices, herbs, legumes, leaves, and even tree bark.

Compared to other types of Polyphenol, tannins have large molecules. 

This allows them to easily bind with proteins, carbohydrates, minerals, cells, digestive enzymes, and other molecules.

For this reason, they’re often used in fabrics, leathers, and inks. And because of their antioxidant properties, medicines too.

And when it comes to tea, tannins and caffeine (an alkaloid) work together to create one tasty cuppa.

Tannins Breakdown

  • Plant Compound w/ Large Molecules
  • 500 to 3000 Molecular Weight
  • 20,000 Daltons (Mass)
  • Polyphenol
  • Water-Soluble
  • Heat Stable
  • Regulates Plant Growth
  • Natural Insect Repellant
  • Two Groups: Hydrolysable (Gallic Acid) and Condensed (Flavonoid Polymers)
  • Astringent Taste
  • Antioxidant, Antibacterial, Anti-inflammatory, Anticarcinogen, and Cardioprotective Properties

What Do Tannins Taste Like?

If you’ve ever over-brewed a cup of Earl Grey tea, then you’ve already tasted tannins at their worst.

Tannins produce quite a bitter taste. And sometimes, a dry puckering sensation, known as astringency

If you’re not sure what that is, it’s like someone has sucked all the moisture out of your mouth.

They can even change the texture and mouthfeel of your tea, turning a once tasty Earl Grey into something dry, chalky, and utterly undrinkable.

Stewed tea, anyone?

Other Sources of Tannins

Tannins contribute to both the flavour and the colour of tea. 

And as a general rule, the higher the tannin levels, the darker the colour.

In addition to tea, tannins are also in:

  • Coffee
  • Red wine
  • Pomegranates
  • Plums
  • Olives
  • Walnuts
  • Chickpeas
  • Black-eyed Peas
  • Lentils
  • Cocoa (Chocolate)
  • Raspberries
  • Blackberries
  • Strawberries
  • Grapes
  • Apple juice
  • Persimmon

Does Earl Grey Tea Contain Tannins?

Yes. All teas from the Camellia sinensis plant contain tannins. 

And this includes black tea – what Earl Grey is made from

What About Decaf Earl Grey?

Yes, decaffeinated Earl Grey still contains tannins. 

That’s because caffeine and tannins are two entirely different compounds. 

So, while the caffeine has been removed, the tannins remain.

Types of Tannins in Earl Grey Tea

There are four main types of tannins in Earl Grey tea.

1. Epigallocatechin Gallate

One of the leading types of tannin in Earl Grey tea is epigallocatechin gallate (EGCG).

This tannin helps with inflammation. It also protects against cellular damage and chronic illnesses. 

EGCG is great for the skin. And it’s sometimes used in weight loss treatments.

2. Theaflavins

Black tea contains high levels of theaflavins and thearubigins. 

Theaflavins are one of the reasons for Earl Grey’s many health benefits.

And they’re used as medicine to treat high cholesterol, heart disease, and obesity. Theaflavins can also help stabilise blood sugar levels.

3. Thearubigins

Ever wondered where Earl Grey tea gets its colour? Well, that’s thanks to thearubigins. 

Formed during oxidation, thearubigins are the reddish brown pigment in black tea. 

They also make up 70-80% of the total phenols. 

4. Ellagitannin

Finally, Earl Grey tea also contains ellagitannin.

While more research is needed, ellagitannin may promote the growth of beneficial gut bacteria. And it has the potential to reduce the growth and spread of cancerous cells.

Ellagitannin also has strong antioxidant and anti-inflammatory properties.

Health Benefits of Tannins

Are Tannins Good For You?

Research suggests that tannins may protect against chronic illnesses such as:

  • Heart Disease
  • Lipid Peroxidation
  • Cancer
  • Brain Disease

Tannins may also help to:

  • Protect Against Allergies
  • Regulate Blood Sugar Levels
  • Inhibit Adipogenesis (weight loss)
  • Balance Gut Bacteria
  • Treat Depression
  • Reduce Stroke Risk

Antioxidant Properties

The antioxidant properties of tannins fight free radicals. Something that’s linked to cellular oxidative stress and degradation.

This suggests that drinking Earl Grey tea can help with a range of degenerative diseases.

Antibacterial Properties

Tannins also contain antibacterial, antimicrobial, and antiviral properties.

This allows them to fight off many pathogens that can affect your digestive system.

As well as stop the growth of bacteria, including:

  • Staphylococcus
  • Candida Albicans
  • Campylobacter Jejuni
  • Helicobacter Pylori

And when combined with antibiotics, the tannins in Earl Grey tea can combat antibiotic-resistant bacteria such as Staphylococcus aureus (MRSA).

Anti-Inflammatory Properties

Ellagitannin (a hydrolyzable tannin) contains anti-inflammatory properties. 

And it may help to combat chronic inflammation of the gut, relieve pain, and reduce swelling.

Side Effects of Tannins

Tannins have considerable health benefits. But they also have some downsides. 

For one, they can act as anti-nutrients by interfering with medications, reducing nutrient absorption, and hampering digestion. 

Here’s a full breakdown.

Reduced Nutrient Absorption

Research suggests that tannins can decrease iron absorption.

That’s because tannins bind with the iron present in plant-based foods, making them redundant. As a result, the body can no longer absorb it. 

While drinking tea won’t cause iron deficiency alone. It can be problematic for already iron deficient (anaemic) individuals.

To limit this risk, drink tea between meals. And avoid drinking Earl Grey tea with iron-rich foods.


If consumed on an empty stomach, the tannins in tea can cause nausea. 

Luckily, there’s a simple solution. Add milk! 

Or, if you don’t fancy that, drink your Earl Grey alongside some food – cake goes rather nicely.

The proteins (from milk) and carbohydrates (from food) bind with the tannins to reduce irritation to your digestive system. 

Jaw Pain

The astringency and bitterness of tannins may cause jaw pain. 

When you drink something particularly sour, bitter, or astringent, your parotid saliva gland goes into overdrive. It’s the same for drinks like red wine which is also high in tannins.

Luckily, this problem can be easily solved. 

Simply apply a chilled tea bag to the affected area and let the anti-inflammatory properties of tannins work their magic.

Medication Blocker

Like iron absorption, tannins can block some medications. 

While some medications (e.g. nadolol) can increase due to the tannins. Something that’s equally problematic. 

So to be on the safe side, always check with your doctor or pharmacist before consuming Earl Grey with prescribed medication. 

Tannin Levels in Tea

While Earl Grey contains tannins, the tannin level in your cup depends on a few factors. 

And this includes the tea type. 

Typically, black tea has the highest levels of tannins. While green tea has one of the lowest. 

In this study, the tannin content of black tea ranged from 11.76% to 15.14%. 

In contrast, the highest recorded green tea tannin content was only 3.11%.

But of course, not all black teas are created equal. 

If you want an Earl Grey with a high tannin content, then a high-quality Assam base is the best choice.

For those after a black tea with a lower tannin content, an Earl Grey made with a Darjeeling (first flush) base is what you need.

What Affects Tannin Levels in Tea?

  • Water Temperature
  • Steep Time
  • Tea Type
  • Altitude
  • Processing Style
  • Tea Quality
  • Milk
  • Teaware (Yixing clay)
  • Foods High in Vit C (Citrus)

Are Tea Tannins Good or Bad For You?

While tannins may have some unwanted side effects, they’re also extremely beneficial to your health.

And without tannins, that cup of Earl Grey tea just wouldn’t be the same.