Is oolong tea high in caffeine?

Oolong tea has been praised for centuries for its many health benefits, including its impact on weight loss. But what about its caffeine content? Is it higher or lower than in other teas?

In this article I will explain:

• what are caffeine and theine
• what are caffeine and theine's health benefits
• what are the health risks related to caffeine and theine
• what is the oolong tea caffeine content

What are caffeine and theine

Caffeine is a psychoactive substance found in the seeds, nuts, or leaves of many plants native to Africa, Asia and South America, the most known of which are coffee beans. It helps the plant to protect themselves against herbivory.

From the known psychoactive substances, caffeine is the most widely consumed worldwide and its use is generally not regulated. While it is widely believed that caffeine can be found in coffee but tea contains theine, theine is actually the same substance as caffeine, as per the research of Carl Jobst from 1883.

Interestingly enough, raw tea leaves contain more caffeine than raw coffee beans but as the preparation of tea requires less raw substance than the preparation of coffee, a cup of infused tea contains less caffeine than a cup of coffee.

What are the caffeine and theine health benefits

Caffeine is generally thought to enhance learning and memory, reaction time, wakefulness and concentration. That's the reason why tea drinking became quickly popular among Buddhist monks who used it to stay awake during their long meditations.

Some studies consider caffeine as a mild euphoriant and it is said to reduce the risk of depression if consumed in moderate quantities. Another assumed benefit of caffeine, albeit not yet fully confirmed by research is its possibility to decrease the risk of Alzheimer disease. 

Apart from the caffeine benefits on the psyche, it is also considered to enhance athletic performance.

What are the health risks related to caffeine and theine

The most common adverse effect of caffeine is its impact on sleep. Caffeine is a stimulant and its excessive consumption can lead to mild anxiety and insomnia. Later in this article I will show how to decrease the caffeine content in tea.

The very benefits of caffeine lead to the fact that it's easy to start consuming it in too large quantities. In some studies (although not all) it is considered as being addictive. Caffeine overdose can lead to nervousness, irritability, restlessness, insomnia, headaches, and palpitations.

Excessive consumption of caffeine is advised against for pregnant or breastfeeding women.

What is the oolong tea caffeine content

As mentioned, while 1kg of tea leaves contains more caffeine than 1kg of coffee beans, a tea infusion contains less caffeine than a cup of coffee.

Furthermore, there are huge differences in the caffeine content of different types of tea and the caffeine content can be reduced or increased depending on the infusion time.

The authors of my favourite book on tea, Tea: History, Terroirs, Varieties, carried out fascinating research on caffeine content in the infusions of different types of tea. According to this research, the Japanese green teas such as Matcha, Sencha and Gyokuro have the highest caffeine content - more than 100 mg for 250 ml for Matcha! Among teas with the lowest caffeine content - less than 20 mg for 250 ml - there are many oolong teas, in the following order:

• Dong Ding oolong tea (from Taiwan) - 20 mg of caffeine for 250 ml of tea
• Tie Guan Yin or Iron Goddess of Mercy (from Fujian in China) - 17 mg of caffeine for 250 ml of tea
• Mi Lan Xiang oolong tea and Rou Gui oolong tea - 16 mg of caffeine for 250 ml of tea

For the sake of this research the teas were infused "Western style" which means, in a Western, large teapot and for a few minutes. Yet, the caffeine content can be further reduced if the tea is infused Gongfu style - in a small teapot or in a gaiwan and for a very short time. The caffeine content can be even 3 to 4 times lower if the infusion time is shortened to under one minute.