Oolong Tea In-Depth: Caffeine, Origins, and Types
Oolong tea may not be as well known as green tea or black tea, but it's certainly popular among the tea lover community. At Zest Tea, we enjoy experimenting with our range of high-caffeine green and black teas, but we enjoy a cup of oolong too.
If you're curious about oolong tea, what it is exactly, how much caffeine it contains, where it originated, and what it may taste like, this is the article for you. Our in-depth guide to oolong teas covers everything you need to know.
What is Oolong Tea?
Oolong tea is a type of tea that's made from the leaves of the Camellia sinensis plant. The leaves are picked, withered, oxidized, and dried to create the tea leaves you can steep in hot water to make a cozy cuppa at home.
Like green tea, black tea, white tea and several other specialist tea types, oolong is made from varieties and cultivars of the Camellia sinensis plant which originates in China. What separates oolong tea from other tea varieties is the level of oxidation.
The oxidation process turns each leaf from green and fresh to brown and rich. Black tea is heavily oxidized while green tea is lightly oxidized.
The leaf that's used to make oolong tea, however, is partially oxidised.
Neither Black Tea Nor Green Tea
The partial oxidation of oolong tea is what makes it so special and so versatile! While black teas can have different flavor notes (malty vs bitter, for example) they all have that distinctive black tea richness and tannins.
But two oolongs can be very different. A lightly oxidized oolong tea may have grassy notes similar to green tea, while a heavily oxidized oolong tea will have richer notes that remind you of black tea. Two oolong teas can have nothing in common, yet still be classified as oolong. Oxidation can be anywhere from 8% to 85%. 1
Oolong is often dried and rolled into different shapes as well. Read about 5 popular oolong tea types below to find out just how versatile and unique oolong tea leaves can be.
A Brief History of Oolong Tea
There are a few theories and legends about the exact origins of oolong tea, but it's undoubtedly of Chinese origin and likely dates back several centuries. In China, "oolong" literally means black dragon tea, although it's sometimes spelt as "wulong". This lends itself to one origin theory in particular.
According to the story, 2 Wu Liang was distracted while picking tea leaves, forgetting to dry them while he was hunting a river deer. When he remembered to collect his tea a day later, he noticed the leaf color had changed and, once fired, the tea produced a mellower, more aromatic flavor (because it had partially oxidized overnight).
Over time, Wu Liang tea became referred to as wu-long tea instead, and so oolong was born.
Today, the majority of oolong grown in China is from the Fujian region, with the Wuyi Mountains and Anxi area producing the most famous oolongs. However, you can also find many oolong teas produced in Taiwan as well.
What Does Oolong Taste Like?
Oolong tea often has a fragrant aroma - sometimes it's subtle, other times it's quite bold. The brewed tea has a broad spectrum of potential flavors, depending on the cultivar of tea plant and the level of oxidation.
Lighter oxidations will be crisper, with grassy green tea notes but more richness and a full body. Darker oxidations can have malty and nutty notes, or even mineral rock flavors that are quite strong.
If you enjoy drinking green and black teas, or are looking for a new type of tea to try, oolong is a good choice. You can find something similar to your usual cup of tea, or explore an entirely new flavor, all within one tea type.
5 Popular Oolong Tea Types
If you want to start drinking a cup of oolong tea per day, these 5 widely consumed Chinese and Taiwanese oolongs are a great place to start.
Jin xuan, milk oolong, is a lightly oxidized Taiwanese variety. It's our recommended top choice for novices as it has a smooth, subtle flavor. It's not dissimilar to a green tea, but also has a slightly floral aroma and unique creamy flavor that's produced naturally by this tea cultivar.
Iron Goddess of Mercy
Tie guan yin is a Chinese oolong from the Anxi region, dating back to the 19th century. Also known as Iron Goddess of Mercy, the complex processing of the tea leaf produces unique flavors. It can go through light or heavy oxidation.
Dan cong, also known as phoenix oolong, refers to a variety of oolong teas sourced from the Phoenix Mountains in the Guangdong province of China. Dancong translates as single bush, and the many phoenix oolong varieties all have unique fragrances. 3
Big Red Robe
Da hong pao, meaning big red robe, is a Chinese oolong from the Wuyi Mountains that is known for a distinct orchid aroma and sweet aftertaste. It can also have a strong mineral flavor, which is why the Wuyi oolongs are often referred to as a Wuyi rock tea.
Ali Shan Oolong
High Mountain oolong from Taiwan grown on the slopes of the Ali Shan mountain is mostly consumed within Taiwan. However, if you can get your hands on this tea type, you'll enjoy mellow, floral and creamy flavors.
How to Brew Oolong
You can brew oolong just like you brew your black or green tea types. General advice is to use water that's roughly 90°C and let the oolong leaf steep for up to 3 minutes. You don't need to add milk or sugar to your oolong before you drink it.
Check out our guide to making tea for more detailed instructions.
Oolong Tea Caffeine Levels
Drinking oolong tea does provide you with energy, however the caffeine content that oolong tea contains may vary widely, just like the flavor of the tea.
The average oolong contains roughly 37 mg of caffeine per 8 oz cup, however some oolongs will have less caffeine and others will have more. Research into the caffeine content of various oolong tea varieties and brands, found that the caffeine levels range from 16.6 to 55.4 mg of caffeine per 8 oz cup. 4
To put that into perspective, an average green tea has a caffeine content of 28mg and black teas have an average caffeine content of 47mg. 5 Oolong tends to fall somewhere in-between.
The caffeine energy you get from drinking tea not only depends on the variety and type of tea, but also the part of the tea plant the leaves are from. For example, white tea made from the buds of the tea plant (silver needle) will have more caffeine than an oolong made from large leaves plucked lower down on the plant.
How Much Oolong Tea Per Day is Healthy?
Tea consumption around the world is hugely popular, and while oolong is considered more of a specialty tea here in the west, it's consumed much more widely and frequently in the areas where it's produced. Drinking oolong tea daily (in moderation) isn't unhealthy. In fact, the FDA recommends limiting your caffeine consumption to 400mg per day, so a cup or two of oolong a day won't get anywhere close to that limit.
Furthermore, regular tea consumption is linked to numerous health benefits thanks to its high antioxidant content. Learn more about the health benefits specific to oolong tea types below.
A Note About High Caffeine Energy Teas
Drinking tea is a great way to boost your energy, but if you're feeling limited by the low caffeine content in traditional teas then high energy teas may interest you. We create high energy teas by boosting the amount of caffeine tea contains. Our black and green tea blends are made with additional tea extract, to naturally increase the energy while still providing the calm and focus you expect from a good tea drink.
If you like oolong, we recommend checking out our fragrant Blue Lady blend next.
Oolong Health Benefits
Numerous studies and research into the effects of tea on our health have found some interesting benefits. The key, as always, is to drink oolong tea in moderation and enjoy a healthy lifestyle too!
Lower Blood Pressure
A long-term study into tea drinking and blood pressure found that habitually drinking oolong has a protective effect and lowers the risk of developing hypertension. 6
Hypertension and high blood pressure are also linked to stress. 7 The L-Theanine present in tea can reduce psychological and physiological stress responses, 8 so that's another way these drinks can reduce your blood pressure and protect your heart.
Aid Weight Loss
A study into the anti-obesity effects of oolong tea found promising signs that oolong could be beneficial for weight loss. The research highlights that the caffeine in oolong could be particularly effective for treating fatty liver and obesity caused by high-fat diets. 9
When it comes to caffeine, however, there are several tea types (including Zest Tea's high energy teas) that provide more than oolong.
Reduce Cholesterol Levels
High cholesterol levels are a huge problem for your health and you may have been advised to lower your cholesterol intake. However, one study into the effects of oolong found that consuming the tea increased excretion of lipids when the participants consumed a high-lipid diet. Put simply, oolong tea could be used to help your body excrete excess cholesterol when you consume too much of it in your diet. 10
Including oolong, tea may reduce the risk of heart disease. Multiple observational studies have found that tea reduces the risk of numerous conditions, including:
- Coronary heart disease by 27%,
- Total stroke by 18%,
- Ischemic stroke by 16%,
- Intracerebral hemorrhage by 21%,
- And cardiac deaths by 24%. 11
Type 2 diabetes results in high blood sugar levels, which can have serious complications. One of the main treatments for type 2 diabetes is taking oral hypoglycemic drugs to lower glucose levels. However, one study has found that oolong tea can be an effective addition to this treatment. Participants would drink 1,500ml of oolong per day, and as a result, had significantly lower concentrations of plasma glucose. 12
Just make sure you take a break between finishing your meal and drinking a cup of tea, especially if you're anemic. Some studies have found that tea can inhibit iron absorption from a meal. 13
Lower Cancer Risk
Drinking green, black or oolong tea has been linked to reducing the risk of ovarian cancer. 14 Furthermore, research has found that the catechin antioxidants in oolong tea could be used to alleviate other ovarian dysfunctions including polycystic ovarian syndrome. 15
In general, green tea is considered the best anti-cancer tea type, thanks to its high catechin content... however most research into green tea and cancer prevention or treatment is inconclusive. 16
Oolong Tea Summary
If you found our article a little t-oolong to read in one go, here's the important facts you need to take away about this interesting drink.
What is oolong tea?
Oolong is a traditional type of tea made from steeping the leaves of the tea plant. It's flavors fall between a green tea and a black tea.
Where does oolong tea come from?
Oolong tea is made from the Camellia sinensis plant which originates in China. Today, most of the oolong tea worldwide comes from China and Taiwan.
What flavor is oolong tea?
Oolong tea falls into a broad spectrum of flavors. Lightly oxidized oolong can be crisp, like a green tea, while a darkly oxidized oolong can be malty and rich, like black teas.
Are there different types of oolong?
Yes, there are many different types of oolong depending on the tea cultivar and oxidation process.
What are the health benefits?
Oolong tea consumption is linked with a lower risk of ovarian cancer, obesity, and heart disease. More research is needed to find a concrete link between tea antioxidants and most benefits, however.
Does oolong tea have caffeine?
Yes, oolong tea contains caffeine. Only herbal teas not made from the tea plant are caffeine-free.
How much caffeine is in oolong tea?
Oolong tea contains 37 mg of caffeine per 8 oz cup on average, but the caffeine content varies widely from one oolong to another.
Is oolong tea good for sleep?
The caffeine in oolong tea may not be good for sleep, however L-Theanine (an amino acid found in various tea types) could improve your sleep by boosting GABA, serotonin and dopamine levels. 17
Which tea is highest in caffeine?
Zest Tea contains up to 150mg of caffeine per cup. Second to our teas, matcha and yerba mate both contain high amounts of caffeine (70mg per cup of tea, or more).
Which tea is lowest in caffeine?
Herbal teas (teas not made from Camellia sinensis) are caffeine-free as they don't contain any caffeine. Amongst oolong tea types, caffeine content tends to be lowest for lightly oxidized tea leaves.