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Oolong Tea Caffeine Levels: How To Brew The Perfect Cup

Oolong tea, a traditional Chinese tea, offers a unique balance of flavor and health benefits. Originating from the Camellia sinensis plant, this tea variety stands out due to its partial oxidation process, which places it between green tea and black tea.

The caffeine content in Oolong tea varies depending on several factors, including the specific type of Oolong and how it is processed. 

On average, an 8-ounce cup of Oolong tea contains about 37 mg of caffeine, which is more than green tea but less than black tea. This moderate caffeine level will stimulate you without getting the jitters associated with coffee and energy drinks.

Don't steep your Oolong for too long. Sorry for the joke but now you will always remember!

A wooden plate filled with dried Oolong rice tea leaves, showcasing their unique rolled shape and vibrant green and brown hues. The plate is placed on a light-colored tiled surface, highlighting the texture and color of the tea leaves.

Health benefits of the caffeine in Oolong tea

Oolong tea consumption has been associated with several health benefits including weight loss, reduced heart disease, and improved mental clarity.


Moderate caffeine consumption has a significant impact on fat oxidation, which is the process of breaking down fatty acids for energy. Herbal tea drinkers have lower risk of high blood pressure due to the protective effects of the tea plant.

Research on caffeine levels of different Oolong tea leaves

We know that low caffeine content is a priority for some people, so we paid for extensive laboratory tests across several tea types to get objective measurements.

It's common knowledge that the temperature of boiling water and steeping times will cause more caffeine to be released into the hot tea. However, we wanted to find out if different varieties of the tea plant under the same conditions would result in different caffeine levels.


Here are the results of our tests, including the range of low-to-high caffeine content based on the ideal water temperature, tea variety, and how long it's been steeped.

Our tests were based on 2 grams of loose leaf tea leaves in an 8-ounce cup of water.

A person pours golden Oolong tea from a white teapot with a bamboo handle into a transparent glass teacup. The teapot is held gracefully over a table set with several small white teacups on black saucers. The background features a rustic brick wall and potted plants, adding to the serene and traditional tea-serving ambiance.

Brewing method to control your caffeine levels

To brew the perfect cup of Oolong tea and control your caffeine levels, follow this traditional brewing method.

Step 1: Measure the Tea Leaves: Use about 1 to 2 teaspoons (2 to 3 grams) of loose leaf Oolong tea per 8 ounces (240 ml) of water.

Step 2: Boil spring water or filtered water: Use high quality water for the best taste. Any tea kettle will do, but you'll need a thermometer to measure the temperature. The ideal temperature for each variety was listed in the previous section. It varies depending on the type of Oolong you're using. Here is a general rule of thumb:

  • Lightly oxidized Oolongs: 185-195°F (85-90°C). This is sometimes described as crab eyes because only little bubble appear in the boiling water.

  • Heavily oxidized Oolongs: 195-205°F (90-96°C). This will bring your hot water to a rolling boil. 

Step 3: Pre-warm the Teapot and tea cups: This is a step that many people overlook. Pour a little hot water into the teapot and your tea cups to warm them ahead of time. Then discard the water. This will help maintain the temperature when you pour it from your kettle.

Step 4: Rinse the Tea Leaves: Pour a small amount of hot water over the tea leaves and immediately discard the water. This step, known as "rinsing," helps to "awaken" the leaves.

Step 5: Steep the Tea: This is an essential step and requires careful attention. Place the tea leaves in the teapot or infuser. Pour the hot water over the leaves, cover the cup and then let it steep for the recommended time.

  • Initial Steep: Let the tea sit for 30 seconds to 1 minute for the first infusion. 

  • Additional Infusions: Increase the steeping time by 30 seconds to 1 minute for each additional round. You can re-steep the leaves 3-5 times, with each infusion offering a slightly different flavor profile.

Step 6: Serve the Tea

  • Pour the tea into a cup using a strainer if necessary to catch any loose leaves. Enjoy the tea while it’s hot.

By following these steps, you can ensure that you are brewing loose leaf Oolong tea properly to enjoy its full range of flavors and aromas.

A close-up view of lush green tea leaves in a tea plantation at sunset. The sun is setting behind distant mountains, casting a warm, golden glow over the landscape. The foreground focuses on the vibrant tea leaves, while the background features a softly blurred view of the plantation and the surrounding hills.

Origins of Oolong Tea

This type of herbal tea originally comes from the Wuyi mountains in Southeast China and is also commonly grown in mountainous regions of Taiwan and Thailand. Our own tea plantation is located in Doi Mae Salong, Chaing Rai, where we cultivate over a dozen varieties of Oolong.

Our tea leaves undergo a meticulous oxidation process, which is longer than green tea but shorter than black tea. That's what gives the tea its distinct flavor and aroma. The leaves are carefully withered, bruised, fermented and oxidized, then heated in a machine to stop the oxidation.

Learn more about our 101 tea plantation where a wide variety of Oolong tea types are grown. You can browse our full selection, including loose leaf and two gram tea bags, pre-measured to align with the research study cited earlier in this article.

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