What Is Fermented Tea? Answered

You’ve may have noticed the Kombucha and fermented food trend. So, are you asking yourself, what is fermented tea? Read on!

Fermented tea is a tea that has been exposed to microbes and allowed to ferment. Regular tea leaves are “semi-fermented” since exposure to air initiates specific oxidative reactions. Full fermentation can occur when yeast, bacteria, or mold are added. 

Fermented tea is believed to have been created by accident in China. China and its neighboring countries (such as Japan, Thailand, etc.) continue to be the world’s primary consumers of fermented tea. 

Furthermore, the purported health benefits of this tea have significantly increased its popularity around the world.

What is fermented tea?
The fermentation process varies across different types of tea.

How Is The Tea Fermented?

The timescale for the fermentation process varies. For some teas, the fermentation process is rapid such as with the red teas in China. However, it can take significantly longer as is the case with teas like blue-green or Pu-erh.

The tea leaves undergo a dramatic oxidative transformation due to their contact with bacteria and moisture. This causes the darkening of the leaves and the release of specific microbes and metabolites that may benefit overall health. Fermented tea has a milder, less bitter flavor than other tea varieties.

The tea is stored in a warm, humid environment, where it’s exposed to yeasts and bacteria after being placed in a hot and humid environment. These microorganisms cause the tea leaves to age quicker. 

There are various techniques for accomplishing fermentation. The first is traditional, artisanal, and ancestral. The tea is fermented for a prolonged period in a warm, humid cellar.

The second method was developed approximately 50 years ago. The process is more modern, industrial, and quicker. Damp tea leaves are stored under an airtight tarpaulin where they are exposed to warmth and humidity for approximately 50 days. 

You may also be interested in our explainers on what is Super coffee and how is Kenyan tea made.

Fermented Tea Names

“Dark tea” or “black tea” is what’s known as post-fermented tea. In China, what we know as black tea is “red tea.” The most well-known Chinese fermented tea is possibly Pu-Erh tea (or Pu’er), which is grown in Yunnan. 

Oolong tea is not actually a fermented tea, although sometimes it is mistakenly called “semi-fermented tea.” It is a semi-oxidized tea, which means it’s somewhere between black and green tea. For this reason, it is also known as blue-green tea or simply blue tea.

You may also be interested in our guide on what is Echinacea tea.

The Most Popular Types Of Fermented Tea

There are three well-known types of fermented tea – Pu’erh tea, Kombucha, and other dark tea. 

1. Pu’erh tea

Pu’erh is a Yunnan-based Chinese dark tea. It is made from Camellia sinensis tea leaves. Raw pu’erh, or aged raw pu’erh, is naturally fermented pu’erh tea.

The other type is ripe pu’erh, or dark pu’erh. Raw pu’erh is nearly always compressed into different shapes and left to age, while ripe pu’erh is usually available in loose-leaf form. Raw pu’erh that has not been compressed is known as maocha.

2. Kombucha

Kombucha is sometimes known as mushroom tea. Kombucha is a beverage made from real tea leaves, sugar, water, and SCOBY, which stands for “symbiotic culture of bacteria and yeast.”

The SCOBY is formed during the fermentation of sugar and black tea and is then utilized to make kombucha. Although herbal tea can also be used to make kombucha, SCOBY is always made with black tea.

3. Other Dark Tea

Pu’erh is a dark tea, but it’s a Yunnan-based dark tea. Other Chinese provinces and even other countries make dark tea as well. All other dark fermented tea that isn’t from Yunnan is just called dark tea, such as the Liu An dark tea from Anhui province in China, or dark tea from Malawi.

Fungi will not be visible on most dark tea leaves, even though they are always present. Nevertheless, there’s a dark tea from Hunan province in China – one of the rare teas where fungi are visible. It is brick-shaped with a particular visible yellow fungus known as a golden flower. 

Japan also makes fermented teas. Awabancha, Batabatacha, and Goishicha are three of the most popular Japanese fermented teas. These teas don’t look like typical compressed dark teas – Awabancha, for example, has large, dark brown, glossy leaves with a flavor similar to roasted hojicha rather than regular fermented dark teas.

What Does Fermented Tea Taste Like? 

The fermentation of tea completely alters its flavor. Forget about the astringent, bitter taste of some certain teas because fermented tea has a smoother, earthier flavor with a strong undergrowth aroma. Hence, the Chinese Pur Erh fermented tea is renowned for taking us to the heart of the forest, as close to ancestral nature as possible.

Potential Fermented Tea Benefits

Some of the purported health benefits of fermented tea include boosted immune system, improved digestion, high energy levels, increased circulation, reduced inflammation, and heart health. 

Boosted Immune System

Fermented tea has antibacterial and antibiotic properties, even though it is made with the help of microbes. These can help balance bacteria levels in your gut, which helps keep your system protected.

Improved Digestion

The fermented tea is usually rich in probiotics, which is great news for your stomach and bacterial balance. Probiotics increase the growth of good bacteria in the gut, which is essential for speeding up digestion and ensuring optimal absorption of nutrients.

High Energy Levels

Fermented tea contains a little caffeine. Although there isn’t as much caffeine as coffee, the other benefits of fermented tea compensate.

Increased Circulation

Fermented tea can increase circulation in the body by optimizing cardiovascular function and increasing iron absorption. More red blood cells can be produced when iron levels increase.

Reduced Inflammation

After fermentation, some of the antioxidants and anti-inflammatory compounds present in traditional teas are increased. This can significantly help your body to reduce inflammation and chronic pain.

Heart Health

Fermented tea has also been shown to help lower triglyceride levels in the body, which is crucial for heart health. Triglycerides are linked to blood vessel and tissue breakdown, which raises the risk of heart attacks and strokes.

Risks & Side Effects

While there is some evidence that fermented teas offer many health benefits, the study is limited. To fully comprehend the medicinal potential of this drink, large-scale human trials are required. Fermented tea comes with some risks and side effects as well, including:

Risk Of Contamination

Kombucha is often homemade, which may not be sterile. Fermented tea that is contaminated can lead to liver damage, metabolic acidosis, and anthrax infections on the skin.

Allergic Reactions

Following the consumption of fermented tea, allergic reactions, jaundice, nausea, vomiting, and head and neck pain have been reported.

Alcohol Content 

If you don’t drink alcohol, you might want to avoid kombucha because it contains a small amount of alcohol. If you like your tea check out our guide on the best teas to drink in the morning.


  • Aisling O'Connor

    Aisling is an Irish food and drinks writer and journalist fueled by coffee and herbal tea. She followed up her journalism degree with nutrition studies. Find Aisling on LinkedIn.