Oolong Tea

Oolong tea leaves

All tea comes from the plant species Camellia sinensis. However, the plant is further classified into two variants: Camellia sinensis var. sinensis and Camellia sinensis var. assamica, known as Chinese tea, and Indian tea, respectively.

Oolong tea is made from the Camellia sinensis var. sinensis plant, as are white, yellow, green and matcha teas. What differentiates these different types of tea is not the plant they come from, but rather how they are processed.

Oolong is a traditional tea produced through a process of partial-fermentation resulting in its unique aromatic smell. It is made with a combination of the leaf and stem (Zeng, 2017), which are wilted, bruised and partially oxidized. While the process for producing oolong involves multiple steps, the key steps include withering the plant under the sun, oxidation and twisting. Because of the fermentation involved in producing oolong, it has some similar qualities to black tea and pu'er tea.

Of all the tea produced globally, only 2% is oolong (Khan, 2007). Most oolong is produced in China (Khan, 2007), and is especially prevalent in South China (Ng, 2017). Many outstanding oolong teas are also grown in Taiwan.

Overview.

The first section of this article is a brief overview of the general flavour of oolong, preparation and health benefits. The next section outlines my product recommendations for oolong tea and the different products I want to try. The third section is an in-depth discussion about oolong, including its origins, how oolong tea gets made, and a comprehensive review of its health benefits. The fourth and final section is a summary of all the key points discussed in this article.

Flavour, Preparation, and Health Benefits of Oolong Tea.

Flavour Profile of Oolong Tea.

The taste of oolong tea varies widely based on how the specific tea leaves are grown, produced, and processed. The flavour of oolong can range from light to full-bodied; on one end of the spectrum, the taste can be floral, sweet and fruity, while on the other end, it can have a woody, toasted and complex flavour.

Oolong flavour and quality are associated with the pot in which the tea is made. In China, which consumes the most oolong, Yixing clay pots are among the most popular. One study examined the chemical compositions of oolong tea made with six different teapot materials (Liao, 2017). The study found that oolong prepared in Yixing clay pots produced infusions that were less bitter and more fragrant. It also found these brews contained more beneficial compounds than tea infusions from other containers. 

How To Brew Oolong Tea.

There are two main ways to brew oolong: a simplified western approach, and using the traditional Gung Fu style.

Western Approach.

Place your loose leaf oolong tea into a tea strainer, pour water that is 87°C (190 °F) over the leaves and allow the beverage to steep for three to five minutes.

Gung Fu Style.

The Gung Fu style of preparing oolong is known as 'small pot brewing' and is the traditional Chinese way of making oolong. In small pot brewing, a gaiwan (or Zhong) is traditionally used.

A gaiwan is a Chinese lidded bowl, without a handle, used for the infusion and drinking of tea. The gaiwan was invented during the Ming dynasty and consisted of a bowl, lid, and saucer.

The main advantage of using a gaiwan is that it allows you to experience how the flavour of an oolong tea evolves over multiple steepings. While the style of the gaiwan used comes down to personal preference, using a glass or crystal gaiwan allows you to see the tea leaves unfurling.

When preparing a 100 ml gaiwan, use between 1-2 teaspoons of oolong tea leaves. Place the loose leaves in the gaiwan, then pour water that is 82 to 96 °C (185 to 205 °F) on the leaves. After five seconds, pour the water out, keeping the leaves in the gaiwan. This step is known as rinsing: it unfurrows the tea leaves for subsequent steepings and also warms the gaiwan.

Next, fill the gaiwan with 82 to 96 °C (185 to 205 °F) water again. This time allow the tea to steep for 10-20 seconds. After this brief period has passed, pour the tea from the gaiwan into small teacups. Using a glass or crystal cup will enhance the flavour of oolong, giving you a more sophisticated tea drinking experience as you progress through multiple steepings.

You can usually steep a single serving of oolong tea four to five times using this method. After you have completed the rinsing stage and the first steeping, add 10-20 seconds to each additional oolong steeping. 

SteepingTime (Quick)Time (Long)
Rinse5 seconds 5 seconds 
First Oolong Steep10 seconds 20 seconds 
Second Oolong Steep20 seconds40 seconds
Third Oolong Steep30 seconds 1 minute
Fourth Oolong Steep40 seconds1 minute 20 seconds
Fifth Oolong Steep50 seconds 1 minute 30 seconds

Brief Summary of The Health Benefits of Oolong Tea.

Oolong tea contains antioxidants and caffeine. Research suggests that drinking oolong tea is beneficial for your health: it may help prevent diabetes, improve heart health, aid weight loss, and protect against cancer.

Tea Recommendations and Personal Thoughts.

Mackenzie Bailey

Founder of The Tea Tribe

I will be honest, a soft smile spreads across my face when I hear someone say "milk oolong”. I particularly enjoy Tao Leaf Tea’s Milk Oolong. I also enjoy “Sweet Scent” Dong Ding Oolong and Tian Chi High Mountain Oolong, both from Tillerman Tea Company, and Alishan Oolong, from Tea Rebellion.

Comprehensive Discussion of Oolong Tea.

Role of Aroma in Oolong Tea Quality. 

A tea's aroma is one of the accepted factors in assessing its quality (Zhang, 2019). Two compounds, theanine and polyphenols, are closely related to tea flavour and tea aroma. Theanine is an amino acid and polyphenols are micronutrients and antioxidants.

Volatile organic compounds cause most scents; therefore, various volatile compounds are essential to tea aroma (Zheng, 2016). The specific factors influencing tea volatiles are tea cultivar, growing environment, processing method and storage of tea (Zheng, 2016).

Shaking the tea leaves is a crucial manipulation in making oolong tea and contributes to the formation of flavour and fragrance in oolong tea (Lin, 2016). Changes in the compounds that trigger our perception of aroma change over time, which is why fresh oolong can smell very different from aged oolong (Kuo, 2010).

Role of Altitude In Oolong Taste.

The taste quality of oolong tea relates directly to the cultivation altitude (Chen, 2014): the higher the altitude, the less astringent taste the tea has.

Catechins and their derivatives generally cause the bitter taste (Chen, 2014), so tea drinkers should be mindful of a general trade-off. Bitter oolong tea may have a higher concentration of antioxidants, while smoother, sweeter oolong may have comparatively fewer antioxidants.

Three Main Types of Oolong Tea.

There are multiple types of oolong tea, but Fujian, Guangdong and Taiwanese oolong tea are the three most famous.  

Fujian Oolong.

Fujian is a vital tea producing province on the southeast coast of mainland China. Within Fujian, two regions are responsible for most of the province's tea production: the Wuyi Mountains in the north and Anxi County in the south. While both areas are important, the Wuyi Mountains are more illustrious.

The Wuyi Mountains are home to some of China's most famous and expensive oolong teas. Si Da Ming Cong is a collective term referring to four popular types of Wuyi oolong tea: Da Hong Pao (Big Red Robe), Shui Jin Gui (Golden Water Turtle), Tie Luo Han (Iron Arhat), and Bai Ji Guan (White Cockscomb).

Anxi County also produces noteworthy oolong teas. The first is Tieguanyin (Iron Goddess of Mercy), one of China's famous teas. The second is Huangjin Gui (Golden Cassia or Golden Osmanthus), which has a fragrance flavour and is similar to Tieguanyin.

Guangdong Oolong.

Guangdong (also called Canton province) is a coastal province located in southern China. The capital of Guangdong is Guangzhou, and the name of the city is sometimes attached to the province's tea, as in the case of "Guangzhou Milk Oolong" from DavidsTea.

Guangdong province is famous for Single Bush Dancong ("Phoenix Oolong") tea. Initially, the term Dancong meant "phoenix teas all picked from one tree." However, the name has evolved and is now a generic term for all oolongs from the Phoenix Mountain.

Dancong teas are a family of oolong teas famous for their ability to naturally replicate flavours and aromas of other plants. Dancong teas are particularly good at imitating the taste and smell of fruits and flowers, like an orchid, cherry blossom and grapefruit. 

Taiwanese Oolong.

Taiwan is known for its high-quality oolong tea (Chien, 2016), and the many different types produced. It wasn't until the 18th century that tea cultivation began in Taiwan, and since the 1970s, tea production has increased. Many of the teas grown in Taiwan are similar to the teas grown in Fujian province.

Taiwan is a relatively small island, but it has a variable climate and varied geography, both of which shape Taiwanese tea production. The extreme fluctuations in weather conditions mean the taste and quality of tea can change dramatically from year to year. The nation's low-lying regions and high mountains allow for different types of tea to be grown in this small country. Taiwanese teas cultivated at high elevations produce a unique sweet taste and sell for a premium price.

Taiwan's high domestic demand for oolong tea means that much of the tea produced in Taiwan is consumed there. Because of this high consumer demand, some tea manufacturers mix lower quality leaves with genuine Taiwan oolong tea to increase profits. For tea drinkers, this means two things: first, buy Taiwanese oolong from a company you trust, and second, if you are unsure of the vendor, ask if the product has undergone a 2-DE test, and what the results were. This scientific procedure can pinpoint a specific tea's origin with 95.5% accuracy. 

How Oolong Tea Gets Produced.

Oolong is partly fermented or partly-oxidized, whereas green tea undergoes no oxidization, and black tea undergoes 100% oxidation. Oolong can be oxidized between 20-80% (Shibu, 2017), meaning oolong, as a style of tea, encompasses a wide range of tastes. The general process used to produce oolong is plucking, wilting, bruising, oxidation, fixation shaping, drying and curing (Tea Processing, Wikipedia, 2019).

Health Benefits of Oolong Tea.

Oolong tea contains low amounts of caffeine and several antioxidants. Theasinensins (polyphenol flavonoid) are the bioactive compounds in oolong tea (Hisanaga, 2014).

Research has shown some real and suggested health benefits from drinking oolong tea. As a partially fermented tea, it contains a relatively high number of catechins (Khan, 2007), including catechins epicatechin (EC) and epigallocatechin (EGC), together with their derivatives (Chen, 2014), but has only minor amounts of epigallocatechin-3-gallate (EGCG). The wide range of oxidation in oolong causes differences in their active metabolites (Shibu, 2017). 

Weight Loss.

Oolong tea is a traditional Chinese tea long believed to be beneficial to weight management (Komatsu, 2003).

Studies on the influence of tea on glucose metabolism have produced inconsistent results (Baer, 2010), although one study found oolong tea performs well in reducing obesity and controlling diabetes (Ng, 2017). Another study found oolong (and black tea) decreased body weight gains (Yang, 2001)(Khan, 2007), while another study found oolong tea consumption caused a decrease in body fat, but not total weight (Yamashita, 2014). Some studies suggest oolong tea may be less effective than green tea or matcha for weight loss (Yang, 2001). However, other research contradicts this by suggesting oolong tea may be more effective than green tea at driving weight loss because of how it interacts with short-chain fatty acids (Rothenberg, 2018).

Cancer Protection.

Tea catechins, including those in oolong, have a chemopreventive effect on carcinogens in the liver (Matsumoto, 1996). Oolong tea can help prevent cancerous cells developing (Ng, 2017), and its consumption is associated with a decreased risk of oral cancer in smokers and alcohol drinkers (Chen, 2017).

When it comes to how tea might help prevent cancer, it is essential to understand that any potential benefits are spread across a spectrum. For example, one tea like oolong may help prevent cancer, but its chemopreventive effect may be less than other types of tea, like matcha. Oolong tea sits somewhere in the middle of the chemopreventive spectrum. For comparison, oolong has a higher inhibitory effect than black tea on cancer (Khan, 2007). 

Overall Health.

Research suggests that oolong tea is effective in reducing triglycerides and LDL-cholesterol (Khan, 2007). Consumption of oolong tea is associated with 3%, 12% and 7% lower blood total cholesterol, TAG and LDL-cholesterol levels, respectively (Yi, 2013). Lowering triglycerides and LDL-cholesterol can help protect against heart disease and strokes.

Oolong offers significant protection against Aβ-evoked neurotoxicity (Li, 2019), an significant health benefit. Aβ is associated with the development of Alzheimer's disease.

Oolong tea provides cardio-protective benefits during hypoxic situations when the body or region of the body is deprived of oxygen at the tissue level (Shibu, 2017). This finding suggests that oolong may be worthwhile to bring on hikes in high mountainous regions where the oxygen level is lower.

Summary.

Oolong is a semi-oxidized, partly-fermented tea. Like green tea and white tea, oolong is made from the Camellia sinensis var. sinensis plant.

Oolong tea has a long history of production and consumption; however, it is generally limited to Asia. It is only relatively recently that oolong is growing in popularity in North American markets.

There are three regions where oolong grows: Fujian, Guangdong and Taiwan. Milk oolong is the most widely known oolong in North America, and it comes from Taiwan. The taste of oolong can vary dramatically from light, floral and butter-like to full-bodied and complex. Oolong grown at a higher elevation is generally sweeter in flavour.

There are two ways you can brew oolong.

  • Western approach: Place your loose leaf oolong tea into a tea strainer. Then pour water that is 87°C (190 °F) over the leaves, allowing the beverage to steep for three to five minutes.
  • Gung Fu style: Gung Fu style of preparing oolong is known as small pot brewing and is the traditional Chinese way of making oolong. Either a gaiwan or small clay pot is used to brew the tea.

In the comments below, share your favourite oolong tea!