Oolong Tea, the blue tea

What is Oolong tea?

Oolong tea (also known as blue tea, or wulong tea) is a semi-oxidised tea from China and Taiwan, with a level of partial oxidation ranging from 10 to 70%. It occupies a unique place between green tea (unoxidised) and black tea (fully oxidised), with an aromatic range that spans from the most delicate florals to the deepest roasted notes. Its name means "black dragon" in Mandarin, a reference to the twisted shape of the tea leaves after processing.

The term "Oolong" comes from the Chinese "Wu Long". Several names coexist within this family: wulong tea, blue-green tea, or simply blue tea. This variety of names reflects the sensory richness of the category, where each variety has its own distinct character depending on the terroir, cultivar and the producer's expertise. For a detailed overview of this great family, its cultivars and processing approaches, see our complete guide to Oolong tea.

Origins and terroirs of Oolong tea

The historic home of Oolong tea is Fujian Province, on the south-eastern coast of China. It is here, among the Wuyi mountain ranges and around the city of Anxi, that the first oolongs were born in the 17th and 18th centuries. Guangdong, in the far south, also produces notable oolongs, most famously the Dan Cong teas of Phoenix Mountain, each grown from a single cultivar. In Taiwan, oolong became a true national speciality from the 19th century onwards, when immigrants from across the strait brought both plants and techniques with them. Today, the island of Taiwan produces some of the most celebrated oolongs in the world, including Dong Ding and the Milky Oolong Jin Xuan, grown in the Nantou district.

Semi-oxidised tea: a balance between green and black

What sets Oolong tea apart from all other tea families is its semi-oxidation process. After harvesting, the leaves are first withered in the sun, then gently tumbled to begin oxidation. The tea master then halts this stage at precisely the moment of his choosing, using a rapid heat treatment to deactivate the enzymes responsible for browning. The resulting degree of oxidation, ranging from 10% for the greenest oolongs to 70% for the most roasted, entirely determines the final sensory profile. The same cultivar can therefore yield two radically different oolongs depending on the producer's decision. This artisanal signature makes semi-oxidised tea the most expressive category in the world of tea.

History and heritage of Oolong tea

The history of Oolong tea stretches back to the Song dynasty (960–1279), though the semi-oxidation technique as we know it was codified later, during the Ming and Qing periods. Legend tells of a hunter from Fujian named Wu Liang who, distracted by a deer, forgot his basket of freshly picked leaves. By the time he returned, the leaves had begun to oxidize, giving rise to an entirely new sensory profile. Over the centuries, Oolong became a tea prized by emperors and a symbol of southeastern China, celebrated for its floral fragrances and remarkable balance on the palate. The legend is a reminder that the finest flavors often spring from happy accidents.

The arrival of Oolong in Taiwan in the 19th century marked a turning point for the entire category. Mainland immigrants brought with them both the plants and the production techniques, but the island's humid climate, mountain altitudes, and volcanic soils offered growing conditions unlike anything found before. Taiwanese producers gradually developed their own approaches: ball-rolled oolongs, lighter oxidation levels, charcoal roasting. From this creative ferment emerged iconic cultivars such as Jin Xuan (Cultivar No. 12, developed in 1981 by the Taiwan Tea Research and Extension Station), which gives our Milky Oolong its naturally creamy, warm-milk character.

The great varieties of Oolong tea

The Oolong family gathers around twenty major varieties, each recognizable by its cultivar, terroir, or processing technique. Below are the most celebrated styles you will encounter among tea enthusiasts and throughout our selection.

• Tie Guan Yin: from the Anxi district in Fujian, a lightly oxidized Oolong with refined orchid notes and a silky finish, one of the pillars of the category.
• Da Hong Pao: a grand cru from the Wuyi Mountains (Fujian), renowned for its complex mineral aromas and deep charcoal roast.
• Dong Ding: a Taiwanese Oolong from the Nantou highlands, sitting between green and roasted, admired for its balance of vegetal and caramel notes.
• Baozhong (Pouchong): a very lightly oxidized Taiwanese Oolong (10–15%), close to green tea in style, with fresh, gently floral aromas.
• Dan Cong: from Phoenix Mountain (Guangdong), each Dan Cong is grown as a single-tree cultivar and crafted to echo a specific aroma (orchid, honey, gardenia).
• Shui Xian: a moderately roasted Wuyi Mountain Oolong with mineral and woody notes, a classic of southeastern China.
• Jin Xuan: the Taiwanese cultivar at the heart of Milky Oolong, naturally expressing a soft, creamy signature.

How to Brew Oolong Tea?

Brewing Oolong takes a little care when it comes to temperature and steeping time, as its delicate aromas don't respond well to water that's too close to boiling, or to hasty measuring. The Western approach, straightforward and unfussy, is perfectly suited to everyday enjoyment. The traditional gong fu cha method, rooted in Chinese tea culture, goes further: by steeping multiple short infusions in a small clay teapot, it draws out the full depth of a fine Oolong.

The Western approach: simple and quick

• Use filtered water heated to between 80 and 90 °C, depending on the level of oxidation (the greener the Oolong, the lower the temperature).
• Measure approximately 3 to 5 g of tea leaves per 200 ml of water, roughly a heaped teaspoon per cup.
• Steep for 1 to 3 minutes for the first infusion, adding a little more time for each subsequent one.
• The leaves can be re-steeped 2 to 4 times on average, with certain Taiwanese varieties holding up beautifully for up to 6 infusions without losing their character.

The gong fu cha technique for exceptional teas

For premium Oolongs such as Tie Guan Yin Premium or Da Hong Pao, the gong fu cha approach (literally "tea made with skill") elevates the aromas to another level. A small porcelain or zisha (Yixing clay) teapot is used, with a generous leaf-to-water ratio (5 to 7 g per 100 ml) and very brief steepings (10 to 30 seconds), repeated 6 to 10 times. Each infusion reveals a different facet, like a gradual journey into the heart of the garden where the tea was grown. A well-seasoned teapot only adds to the experience. For a deeper dive, visit our complete brewing guide.

When to Enjoy Oolong Tea?

With its moderate caffeine content and richly layered sensory profile, Oolong is wonderfully versatile throughout the day. In the morning, roasted Oolongs and medium-oxidized Taiwanese varieties provide a gentle, steady energy, without the edginess of coffee. At midday, more floral Oolongs such as Baozhong or the Jianxing Blue Tea make for a refined pause, ideal alongside a pastry or at the end of a meal. Later in the day, opt for something softer, such as our Orange Blossom Oolong, steeped lightly so as not to disturb sleep.

Oolong also shines as an iced tea, especially in summer: cold-steep in the refrigerator for 4 to 6 hours, using 12 g per litre of water. The floral and fruity notes of a Taiwanese Oolong lend themselves beautifully to cold brewing, which softens any bitterness and preserves every nuance. Add fresh ginger and a squeeze of lime for a sparkling non-alcoholic cocktail that feels genuinely special. A slice of fresh fruit on the side, such as peach or fig, rounds the experience out perfectly.

When it comes to food pairings, roasted Oolongs pair naturally with caramel desserts, dark chocolate, and dried fruits, echoing their warm, toasty notes. Floral, lightly oxidized Oolongs find their match in fresh pastries, almond biscuits, macarons, and rose or orange blossom entremet. For lovers of Asian cuisine, a plain Oolong is a wonderfully refined companion to dim sum, steamed dishes, and sticky rice desserts.

Our Selection of Organic Oolong Teas

Our range brings together around fifteen Oolongs, chosen for their aromatic diversity and garden-quality sourcing. From Chinese classics to contemporary blends, taking in the iconic teas of Taiwan, tea lovers will find both pure, unflavoured Oolongs and aromatic creations, available in 100 g bags or loose-leaf. Five main families shape our selection:

• Pure Chinese Oolongs: Tie Guan Yin with its orchid-like notes, the mineral Shui Xian from the Wuyi mountains, and the fruity Oolong Fu Liang Farm.
• Taiwanese Oolongs: the Milky Oolong with its creamy notes, and the Dongaao Lemon Basil Oolong.
• Indulgent flavoured Oolongs: Peach Vanilla Oolong, Almond Chocolate Oolong, and Fig Melon Oolong.
• Floral and fruity Oolongs: Lady Clochette with lily of the valley, Orange Blossom Oolong, and Orange Oolong.
• Voyage Oolongs: Tibetan Mountain Oolong, Nepal Jun Chiyabari, and Java Halimun Jade.

Every tea in our range is sourced directly from the producer, and the majority of the collection is certified organic.

Storing Oolong Tea: Shelf Life and Best Practices

Among all the tea families, Oolong is one of the most stable in storage, thanks to its semi-fermentation. Lightly oxidized Oolongs keep well for around a year under the right conditions, while roasted Oolongs are best enjoyed within six months to preserve their distinctive toasty signature. To protect the aromas, store your tea away from light, moisture, and strong odours, ideally in an airtight tin kept well away from spices and scented products. The refrigerator is best avoided: its humidity and surrounding smells transfer quickly to the leaves.

Certain heavily roasted, highly oxidized Oolongs can even be aged intentionally: re-roasted every two to three years by a tea master, they develop notes of dried fruit, leather, and cocoa over time, not unlike a fine aged wine. This tradition, most deeply rooted in Taiwan and the Wuyi mountains, makes organic Oolong tea one of the rare teas whose aromatic value can actually grow with time, provided storage conditions are carefully respected. For flavoured Oolongs and modern blends, however, it's best to enjoy them fresh, ideally within the year following purchase. A well-kept, aged Oolong can offer a tasting experience that is truly unforgettable.

How is Oolong Tea Made?

The production process of Oolong tea is one of the most demanding in the world of tea: it involves up to eight successive stages, each one shaping the final profile of the cup. It all begins with a hand-picked harvest, typically limited to the bud and the first two leaves. The leaves are then withered in the sun to allow some of their moisture to evaporate, before being brought indoors for an air withering phase that gently softens the leaf. Next comes tossing, the signature step: the leaves are shaken in bamboo baskets or lightly bruised underfoot, which damages the leaf edges and triggers enzymatic oxidation.

The oxidation that follows is the most delicate phase of all. The tea master watches colour and fragrance closely, stepping in at precisely the right moment to halt the process. This is done through kill-green (fixation): a brief blast of high heat, whether from a wok, steam or a mechanical drum, that deactivates the enzymes driving the browning. The leaves are then rolled, often by hand for premium grades, giving them their characteristic shape: tight balls for Taiwanese oolongs, twisted strips for Chinese ones. A final drying stage stabilises residual moisture. Some oolongs then undergo roasting over charcoal or in a drum oven, developing rounder, toasted notes with remarkable persistence.

The Three Main Oxidation Levels

Oxidation level, which can range from 10 to 70%, is the most defining characteristic of an oolong. Lightly processed oolongs (10–30%), such as Baozhong or modern Tie Guan Yin, retain a leaf colour close to green and offer vivid floral and vegetal nuances. Medium-oxidised oolongs (40–60%), such as Dong Ding or our Fu Liang Farm, develop fruity notes and a more pronounced body. Heavily oxidised oolongs (60–70%), such as certain Da Hong Pao or roasted Dan Cong, show woody, honeyed and caramelised touches that bring them close to black tea, without the bitterness.

Benefits and Characteristics of Oolong Tea

Oolong tea is recognisable by its twisted leaves (in Chinese varieties) or tightly rolled balls (in Taiwanese ones, like our Milky Oolong), ranging in colour from deep green to brown depending on oxidation. In the cup, the liquor is clear and luminous, from golden to amber. Its aroma is complex, shifting between floral, fruity and sometimes woody or roasted notes. On the palate, it bridges the freshness of green tea and the depth of black tea, with a silky quality unique to semi-oxidised teas.

Nutritionally, Oolong tea provides antioxidant polyphenols (catechins, theaflavins, thearubigins) that help the body combat oxidative stress, as noted by the EFSA. It contains a moderate level of caffeine (15–30 mg per 200 ml), balanced by L-theanine, an amino acid with relaxing properties that softens the stimulating effect. Oolong tea is also known for its role in digestion: some studies suggest it may stimulate digestive enzymes and reduce bloating after fat-rich meals, though it is not a medical treatment. To explore these effects further, visit our dedicated page on the benefits of Oolong tea.

Oolong Tea and Metabolic Support

The landmark study Rumpler et al., 2001, Journal of Nutrition found a modest increase in energy expenditure among regular Oolong tea drinkers, linked to its polyphenols and caffeine. These effects remain limited and are no substitute for a balanced diet or regular physical activity. For those looking to support weight management, Oolong tea can be a helpful complement to an overall healthy lifestyle, without any miracle claims. These benefits only apply within the context of an active way of living.

Oolong Tea, Green Tea and Black Tea: What's the Difference?

The Oolong tea family is best understood in relation to its two neighbours. Green tea is fixed immediately after harvest, with no oxidation: it retains the fresh, vegetal character of the leaf, but tends toward a lighter profile. Black tea, by contrast, is fully oxidised, which develops malty, honeyed and woody aromas at the expense of floral complexity. Oolong sits precisely at the crossroads: a lightly processed oolong can evoke a particularly expressive green tea, while a roasted oolong approaches the round, deep character of black tea without its bitterness. It is this aromatic versatility that makes Oolong the most diverse and endlessly fascinating category for tea lovers.

Your Questions About Oolong Tea

Does Oolong tea contain a lot of caffeine?
Oolong tea has a moderate caffeine content, around 15 to 30 mg per 200 ml, less than a cup of coffee. Its L-theanine content softens the stimulating effect, offering a gentler, more sustained energy.

What is the difference between Oolong tea and blue tea?
There is none: "blue tea" is simply the French name for Oolong tea. It refers to the same family of semi-oxidised teas, sitting halfway between green tea and black tea.

At what temperature should Oolong tea be brewed?
Between 80 and 90 °C depending on its oxidation level: the greener and more floral the oolong, the cooler the water should be. Use 3 to 5 g of leaves per 200 ml and steep for 1 to 3 minutes.

How many times can Oolong tea be re-steeped?
Using a Western brewing method, an oolong can be re-steeped 2 to 4 times. Using gong fu cha, premium Taiwanese teas can withstand up to 6 to 10 short infusions, each one revealing a new aromatic facet.

Can Oolong tea help with weight loss?
Oolong tea is not a slimming product. Some studies point to a modest metabolic boost linked to its polyphenols, but this effect remains limited and only applies as part of a balanced diet and an active lifestyle.

How should Oolong tea be stored?
Keep it away from light, moisture and strong odours, in an airtight metal tin, well away from spices. Avoid the refrigerator. Lightly oxidised oolongs keep for around one year; roasted ones are best enjoyed within six months.