lán húdié

Blue butterfly pea tea consists of whole dried flowers of Clitoria ternatea, a tropical leguminous vine, whose infusion yields a deep sapphire-blue colour. In Chinese commerce, the product is known as 蓝蝴蝶 (lán húdié, “blue butterfly”) and 蝶豆花 (dié dòu huā, “butterfly pea flower”). An important clarification must be made at the outset: despite the word “tea” in its common name, this product has no connection to true tea made from the leaves of Camellia sinensis. It is a tea substitute, or herbal infusion (代用茶, dàiyòng chá). The plant is not native to China but to tropical Asia, and the deepest tradition of its consumption is rooted in Thailand, where the flower is called anchan (ดอกอัญชัน, dok anchan). The characteristic colour of the infusion comes from anthocyanins of the ternatin group, and when an acid is added — such as a slice of lemon — the blue visibly shifts to purple and pink.

1. Classification and Origin:

• Type: herbal infusion, tea substitute (代用茶, dàiyòng chá), not tea in the botanical sense.
• Botanical name: Clitoria ternatea L., family Fabaceae.
• Part used: flower (less commonly, buds are also used in blends).
• Origin: tropical and subtropical Asia; the culture of consumption is most developed in Thailand, Vietnam, Malaysia, India, and Sri Lanka.
• Chinese trade names: 蓝蝴蝶 (lán húdié), 蝶豆花 (dié dòu huā).

To state it separately and unequivocally: the product contains no leaves of Camellia sinensis, meaning it is not green tea, not oolong, and not any other true tea. In the Chinese classification of beverages, such infusions belong to the category 代用茶 (dàiyòng chá) — “substitute tea,” prepared from plant materials that are not tea leaves. This is an independent genre of beverage with its own culture of brewing and serving, rather than a “surrogate” for tea.

A legal nuance is also worth noting: the status of Clitoria ternatea as a food ingredient in mainland China is ambiguous — the flower is not included in the official list of new food raw materials (新食品原料, xīn shípǐn yuánliào), which has raised questions from regulators regarding its industrial use in food products. Meanwhile, in the cuisines of Southeast Asia, the flower has been used extensively and for a long time.

2. History and Cultural Significance:

Clitoria is an Old World plant, long known in tropical Asia as both an ornamental and a food plant. The specific epithet ternatea refers to the island of Ternate in the Maluku Archipelago (Indonesia), from where specimens reached European botanists in the 18th century.

• Historical role: in Thailand, anchan infusion (น้ำดอกอัญชัน) is a traditional refreshing beverage, and the flower itself has been used for centuries as a natural blue colouring for rice, desserts, and drinks.
• In China: the product is relatively new, arriving with the trend for “Instagram-worthy” colour-changing drinks and visually striking 花草茶 (huācǎo chá, herbal infusions).

In Chinese everyday culture, blue tea has occupied a niche defined not so much by taste as by visual appeal: it is valued for its colour and for the “trick” of shifting hues. It is found in tea shops stocking herbal blends, in bars and coffee shops as a base for lemonades and cocktails, and in the home use of herbal infusion enthusiasts.

3. Botanical Description and Raw Material:

• Life form: perennial climbing vine reaching 3 m or more in length.
• Flower: papilionaceous type, as with many legumes; most commonly vivid blue with a whitish-yellow “eye” in the centre; white and double-flowered forms also occur.
• Fruit: flat pod containing seeds.
• Raw material: fully opened flowers, dried whole, preserving the “butterfly” shape.

Only the flowers are used for brewing. The seeds and roots of the plant contain irritant and laxative compounds and are not used for consumption — an important distinction between the edible part and the rest of the plant.

4. Terroir and Cultivation Characteristics:

• Climate: hot and humid, tropics and subtropics; the plant cannot withstand frost.
• Soils: prefers light, well-drained soils; as a legume, it enriches the soil with nitrogen through symbiosis with nodule bacteria.
• Main regions: Thailand, Vietnam, India, Sri Lanka, Malaysia.
• In China: grown in the south — on Hainan (海南), in Yunnan (云南), Guangxi (广西), and Guangdong (广东), although a significant share of raw material on the market is imported.

The plant is undemanding, grows quickly, and flowers abundantly and over a long period, making it convenient for smallholdings and home garden plots. This ease of cultivation largely determines the low wholesale price of the raw material.

5. Production Technology:

• Harvesting: flowers are picked by hand at the stage of full bloom, usually in the morning.
• Drying: sun-dried or in dryers at moderate temperature; the key objective is to remove moisture quickly while maximally preserving the blue pigment and the integrity of the petals.
• Sorting: selection of whole, brightly coloured flowers; faded, brownish, and broken ones are discarded.

The technology is simple but demanding in terms of care: anthocyanins are sensitive to heat, light, and oxidation, so overdried or overheated raw material loses colour and turns from blue to a dull brownish hue. The quality of the product is judged first and foremost by the depth and purity of colouration.

6. Organoleptic Characteristics:

• Dry flower: dark blue, almost inky violet, with the “moth” form preserved.
• Infusion colour: transparent, deep cornflower blue; at high concentration — almost blue ink.
• Aroma: faint, herbaceous-leguminous, unobtrusive.
• Taste: very neutral, soft, with a light green-bean note and almost no bitterness or astringency.

The main organoleptic value of the product is visual. The taste is weakly expressed, which is why anchan is often combined with lemon, mint, lemongrass, and honey, and is also used as a colouring base.

7. Chemical Composition:

• Anthocyanins: ternatins — polyacylated pigments named after the specific epithet ternatea; responsible for the blue colour and for the hue shift when pH changes.
• Flavonoids: glycosides of kaempferol, quercetin, and related compounds.
• Other: peptides and other secondary metabolites characteristic of legumes.

Ternatins behave as a natural acid-base indicator: in a neutral medium the infusion is blue; upon acidification it becomes violet-pink; in an alkaline medium it shifts into greenish tones. It is precisely this property that underlies the “magical” colour change upon adding lemon.

8. Health Properties:

• In folk tradition: in Southeast Asia and in Chinese daily practice, anchan is customarily regarded as a “refreshing” beverage; it is attributed with general tonic and “rejuvenating” effects, as well as a connection to skin and hair care.
• What science investigates: research interest is focused on the antioxidant activity of anthocyanins and flavonoids; this refers to laboratory and preliminary data, not to proven clinical effects.

A direct disclaimer is necessary: the product is a food item, not a medicinal substance. Any health claims made in retail trade fall outside the scope of an encyclopedia and should not be taken as medical recommendations. Among the commonly known precautions, it is reasonable to note moderation in consumption, caution during pregnancy and breastfeeding, and caution when taking regular medication — in such cases consulting a specialist is appropriate. Only the flowers have food value; seeds and roots are not used for consumption.

9. Brewing:

• Ratio: approximately 1–2 g of dried flowers (around 5–10 pieces) per 200–250 ml of water.
• Water: soft, temperature 85–95 °C.
• Vessel: transparent glass — in order to see the colour; for this product, this is part of the presentation.
• Time: colour extracts quickly; 3–5 minutes is sufficient.
• Reinfusions: 2–3 successive infusions, with each one yielding a weaker colouration.

The hot infusion is drunk plain or with honey. A cold presentation is very common: the infusion is chilled, poured over ice, a slice of lemon or lime is added — and the blue transforms before the eyes into pink-purple. Anchan is also used as a natural colouring for lemonades, cocktails, jellies, and rice. Prolonged pouring of scalding boiling water is not advisable — excessive heating dulls the colour.

10. Storage:

• Conditions: dry, dark, cool place; airtight, opaque packaging.
• Enemies of the product: light, moisture, oxygen — they destroy anthocyanins, and the colour fades.
• Shelf life: approximately 12–24 months with proper storage; faded, brownish raw material is technically safe but loses its main virtue — colouration.

11. Price and Counterfeits:

• Wholesale price benchmark: around 100 ¥/kg; this is an inexpensive flower raw material, not a rarity.
• What genuine raw material looks like: whole dried flowers of a deep blue-violet colour, yielding a clear blue infusion and turning pink upon addition of acid.

The main market problems are not so much outright substitution with another plant (the flower shape of clitoria is too recognisable) as they are quality issues: faded, old, or overdried raw material of a brownish shade, yielding a cloudy, weak infusion. Batches with synthetic dye added to “revive” the colour are also encountered. A simple domestic test for the naturalness of anthocyanins is the acid reaction: a genuine infusion, when lemon juice is added, should confidently shift to a pink-purple tone. The aforementioned regulatory nuance is also worth keeping in mind: the legal status of the flower as a food raw material in mainland China is ambiguous, so it makes sense to pay attention to the source and intended use of the product.

12. Interesting Facts:

• Genus name: Clitoria was given due to the outward resemblance of the flower to a part of female anatomy — this is reflected in the historical botanical nomenclature.
• Species name: ternatea — from the island of Ternate in Indonesia, from where the first described specimens originated.
• Natural indicator: the infusion changes colour depending on acidity, which is used in bars for “shifting” drinks and even in school chemistry demonstrations.
• Culinary colourant: in Thai cuisine, the flower is traditionally used to colour rice and desserts a blue tone.
• Taste versus colour: this is a rare case of a product valued almost exclusively for its visual effect rather than for taste or aroma.

In Conclusion:

Blue butterfly pea tea is a vivid example of how a herbal infusion made from a plant that is not tea at all occupies its own place alongside tea, without pretending to be it. It is a tea substitute (代用茶, dàiyòng chá) made from the flowers of Clitoria ternatea, which arrived in China from tropical Asia and won affection above all for its striking sapphire colour and the “trick” of turning pink upon the addition of acid. It has a simple, mild taste, an uncomplicated production process, and a low price, while all of its expressiveness rests on ternatin anthocyanins, which are sensitive to light, heat, and acidity.

One should approach anchan with a level head: it is a vibrant food beverage and a natural colourant, but neither a medicine nor “true tea.” If it is appreciated precisely for what it is — for the visual play of colour, for a light serve with ice and lemon, and for its role as a natural pigment — it remains a curious and entirely independent member of the herbal infusion family, deserving of a respectful but honest description.

the teas described here are available from teamotea