Cuìyù wūlóng · new.thetea.app

Taiwanese Jade Oolong is one of the most characteristic representatives of modern Taiwanese breeding, a tea with distinctive floral aroma, created from the Cuì Yù (翠玉, Cuìyù) cultivar, officially registered as Taicha No. 13 (臺茶13號, Táichá Shísān Hào). This variety, developed during the large-scale breeding program of the Taiwan Tea Research and Extension Station (TRES), became a symbol of the successful combination of scientific approach and the island’s tea traditions.

1. Classification and Origin:

Type: Oolong (semi-oxidized tea, qing cha / 青茶, Qīngchá). Oxidation level — approximately 15–20%, which places it in the category of light (lightly oxidized) oolongs.
Category: Taiwanese light oolong of new breeding. Taicha No. 13 (臺茶13號).
Origin: Táiwān (臺灣, Táiwān). The cultivar was developed by the Taiwan Tea Research and Extension Station (茶及飲料作物改良場, formerly — 臺灣省茶業改良場, Táiwān Shěng Cháyè Gǎiliáng Chǎng, TRES) in Táoyuán City (桃園, Táoyuán). Main regions of commercial production: Nántóu County (南投縣, Nántóu Xiàn) — primarily Míngjiān Township (名間鄉, Míngjiān Xiāng) and Sōngbǎilǐng area (松柏嶺, Sōngbǎilǐng); also Chiayi County (嘉義縣, Jiāyì Xiàn) — Ālǐshān area (阿里山, Ālǐshān); New Taipei (新北市, Xīnběi Shì) — Pínglín area (坪林, Pínglín); Yílán County (宜蘭縣, Yílán Xiàn); Taitung County (臺東縣, Táidōng Xiàn).
Geographic coordinates: Mingjian, Nantou — approximately 23°52′ N, 120°40′ E. Elevation of main plantations — from 300 to 600 m a.s.l.; individual plantings in the Alishan area reach 1,400 m.

2. History and Cultural Significance:

History: The emergence of Jade Oolong is inseparably linked with the name of Wǔ Zhènduó (吳振鐸, Wú Zhènduo, 1918–2000) — an outstanding Taiwanese tea scientist, awarded the unofficial title “father of post-war Taiwanese tea” (戰後臺茶之父). A native of Fu’an County (福安) in Fujian Province, graduate of Fújiàn Higher Tea School and student of Zhāng Tiānfú (張天福), he arrived in Taiwan in 1947 and from 1968 headed the reorganized Taiwan Tea Research and Extension Station (TRES), becoming its first director.

As early as 1938, the station had begun a program of artificial hybridization of tea bushes. From more than 5,000 seedlings remaining from the Japanese colonial period, Wu Zhenduo and his team selected promising lines for multi-year field trials. Three outstanding seedlings received working codes 2027, 2028, and 2029, for which farmers gave them nicknames “Er-qi-zi” (二七仔), “Er-ba-zi” (二八仔), and “Er-jiu-zi” (二九仔) — after the last two digits of the code.

After four decades of selection and regional trials, in 1981 (民國70年) the Council of Agriculture recognized two of the three seedlings as new varieties. Seedling 2027 was registered as Taicha No. 12 (臺茶12號) and received the name Jīn Xuān (金萱, Jīnxuān — “Golden Daylily”) in honor of the breeder’s grandmother. Seedling 2029 became Taicha No. 13 (臺茶13號) and was named Cuì Yǔ (翠玉, Cuìyù — “Jade Green”) in honor of Wu Zhenduo’s mother — a gesture of filial piety that became a legend of Taiwanese tea cultivation. The third seedling (2028) was excluded due to excessive similarity to 2029. In 2009, a memorial museum, the “Zhènduo Hall” (振鐸館, Zhènduo Guǎn), was opened at TRES in memory of the great tea scientist.

In 1987, the TRES research group that developed both cultivars was awarded the first Executive Yuán Award for Outstanding Scientific and Technological Achievements (行政院傑出科技人才獎) — recognition of the significance of the new varieties for the economy of tea regions.
Name:
- Cuì Yù (翠玉, Cuìyù) — literally “jade green” or “emerald jade.” The character 翠 (cuì) denotes brilliant emerald-green color, while 玉 (yù) means jade or nephrite. The name refers simultaneously to the color of the tea leaf and to the name of the variety creator’s mother.
- Jade Oolong — English commercial name that emerged when the tea entered the international market. Connected to the cultural significance of jade in Chinese tradition as a symbol of purity, nobility, and harmony.
- Taicha No. 13 (臺茶13號) — official registration designation in the TRES system.
- “Er-jiu-zi” (二九仔) — farmers’ nickname, from the last digits of working code 2029.
Cultural significance: Jade Oolong together with its “brother” Jīn Xuān (金萱) symbolizes the beginning of a new era in Taiwanese tea cultivation — the era of scientific breeding. Until 1981, the overwhelming majority of Taiwanese oolongs were produced from the traditional Qīngxīn Oolong (青心烏龍, Qīngxīn Wūlóng) cultivar, brought from Fujian. The appearance of high-yielding and disease-resistant varieties Cui Yu and Jin Xuan made quality oolong accessible to a wide range of consumers, not just connoisseurs of elite high-mountain teas. The commercial success of these cultivars contributed to the popularization of Taiwanese teas in the world market and became a model for further breeding programs (Taicha No. 17 “Yinxiang,” Taicha No. 19 “Biyu,” Taicha No. 20 “Yinhong,” etc.).

3. Botanical Description and Raw Material:

Cultivar: Cuì Yù (翠玉, Cuìyù), Taicha No. 13, working code — Tainong 2029 (臺農2029號). Hybrid of Camellia sinensis var. sinensis, obtained through artificial crossing: paternal line (花粉, pollen) — Tainong No. 80 (臺農80號, Hankow line / 漢口系), maternal line (花蕊, pistil) — Yìngzhī Hóngxīn (硬枝紅心, Yìngzhī Hóngxīn — “Hard Branch Red Heart”), an old Taiwanese cultivar traditionally used for producing Tieguanyin and medium-oxidation oolongs.
Morphology: Shrub type (灌木型), upright habit (直立型). Small-leaf variety (小葉種). Leaves of broad-elliptical shape, 6–8 cm long, 3–4 cm wide, with pronounced central vein. Young shoots — light green with slight purple tinge; mature leaves — dark green with pronounced gloss. Pubescence (茸毛) — medium. Crown relatively sparse, which distinguishes Cui Yu from the more densely leafed Jin Xuan. According to TRES data, Cui Yu yield is approximately 20% higher than traditional cultivars Qīngxīn Oolong and Qīngxīn Dàmǎo (青心大冇), though somewhat lower than Jin Xuan.
Harvest: Medium-ripening variety (中生種): beginning of spring harvest — first decade of April (one week later than early-ripening varieties such as Sijichun / 四季春, and simultaneously with Jin Xuan). Main harvest seasons — spring (April–May) and autumn (October–November). Harvest standard — flush: bud and two–three upper leaves (一芽二三葉). Thanks to upright habit, both manual and machine harvesting are possible; mechanized harvesting predominates on the flatland plantations of Mingjian.
Raw material requirements: Healthy, undamaged leaves corresponding to harvest standard. Spring harvest is valued higher than autumn due to higher amino acid content and more delicate aroma.

4. Terroir and Cultivation:

Main region: Míngjiān (名間鄉) and Sōngbǎilǐng (松柏嶺), Nántóu County (南投縣) — the largest tea region of central Taiwan, providing a significant share of commercial Cui Yu production. This is where numerous specialized oolong processing factories (茶葉精緻代工廠) are located.
Other regions: Pínglín (坪林) in New Taipei — traditional region of Wénshān Bāozhǒng (文山包種); Yílán (宜蘭), Taitung (臺東), Ālǐshān area (阿里山) in Chiayi County — high-mountain plantings up to 1,400 m.
Growing elevation: Main plantations — 300–600 m a.s.l. Individual high-mountain plantings — up to 1,400 m (Zhangshuhu area / 樟樹湖 in Alishan).
Soils: Red ferrallitic soils (紅壤), rich in iron and aluminum oxides, with acidic reaction (pH 4.5–5.5), providing good drainage and moderate mineral nutrition.
Climate: Subtropical monsoon. Average annual temperature — approximately +21°C. Annual precipitation — approximately 2,000 mm. High air humidity. Frequent morning fogs are characteristic, diffusing direct sunlight and promoting amino acid accumulation in leaves, which softens the tea’s taste.
Agrotechnical features: Modern methods are applied: drip irrigation, inter-row planting of leguminous crops for natural soil nitrogen enrichment (green manuring), shading of bushes before harvest to increase L-theanine content. The share of organic production is growing thanks to government programs supporting ecological farming and mandatory testing for pesticide residues (SGS 470-component test).

5. Production Technology:

Production of Jade Oolong follows the classic technology of Taiwanese spherical (semi-spherical) oolongs (半球型包種茶). Many stages at flatland factories are mechanized.

Solar withering (日光萎凋, Rìguāng Wěidiāo / Solar Withering): Freshly picked leaves are spread in a thin layer on bamboo trays under direct or diffused sunlight for 20–40 minutes to begin moisture evaporation and start enzymatic processes. Leaves lose their initial turgor and acquire softness.
Indoor withering and tossing (室內萎凋與浪青, Shìnèi Wěidiāo yǔ Làngqīng / Indoor Withering and Tossing): Leaves are transferred to a ventilated room where they are periodically tossed by hand or in bamboo drums. Tossing (搖青, Yáoqīng) damages cell walls at leaf edges, ensuring contact between polyphenol oxidase and polyphenols and starting oxidation. The process is repeated 3 to 5 times with increasing rest intervals, total duration — 6–10 hours. At this stage, the characteristic bright floral aroma (品種香) of Cui Yu is formed.
Fixation / “Kill-green” (殺青, Shāqīng / Fixation): When the oxidation level reaches 15–20% (leaf edges acquire reddish tinge while the center remains green), the process is stopped by rapid heating in a drum roaster at approximately 250–300°C for 5–7 minutes. Enzyme inactivation fixes the achieved fermentation level and preserves the green color of the leaf.
Rolling and shaping (揉捻與團揉, Róuniǎn yǔ Tuánróu / Rolling and Ball-Rolling): Leaves are repeatedly rolled in cloth bags (布球揉捻, Bùqiú Róuniǎn — “shaping in cloth ball”), alternating rolling with brief drying. This process is repeated up to 15–20 times and gives the tea its characteristic form of dense semi-spherical granules. Rolling also destroys cellular membranes, enhancing extractability during brewing.
Drying (乾燥, Gānzào / Drying): Final drying is conducted in several stages at gradually decreasing temperature (from 100–110°C to 70–80°C) to remove residual moisture to 3–5% level and fix shape and aroma.
Sorting (揀梗與分級, Jiǎngěng yǔ Fēnjí / Stem Removal and Grading): Removal of stems and broken leaves, sorting of finished tea by size and quality using optical sorting machines and manual selection.
Additional roasting (焙火, Bèihuǒ / Roasting, optional): Standard Jade Oolong is released in “light” (清香型, Qīngxiāng xíng) style without additional roasting. However, part of the production undergoes light or medium roasting (中培火) to impart nutty and caramel notes.

6. Organoleptic Characteristics:

Dry leaf appearance: Tightly rolled semi-spherical granules (球型) of irregular shape, 0.5–1.0 cm in size. Color — from light green to olive-green (翠綠 or 黃綠), with natural gloss on the surface. Short stems may be present. The leaf appears brighter green and thinner compared to Jin Xuan granules.
Dry leaf aroma: Fresh, clean, floral-grassy. The typical varietal aroma (品種香, Pǐnzhǒng xiāng) of Cui Yu is described by the formula “clean aroma striking the nose” (清香撲鼻, Qīngxiāng Pūbí) — these are pronounced notes of white flowers: betel palm flowers (檳榔花, Bīnláng huā), magnolia (玉蘭花, Yùlán huā), jasmine (茉莉, Mòlì). Light creamy-nutty undertones (almond).
Liquor aroma: Bright, high, floral. Notes of jasmine, magnolia, and orchid dominate, complemented by creamy-vanilla and sweet undertones of young corn. The aroma is persistent, unfolding in layers from infusion to infusion.
Taste: Soft, smooth, oily (滑, huá). Sweet floral profile with light, refreshing acidity of green apple. Astringency is minimal. Aftertaste (回甘, Huígān) — long-lasting, sweetish, with floral trail. Tea body is light but rich in aromatic nuances.
Liquor color: Clear, from light golden (蜜黃) to pale amber, with pearlescent sheen. With light oxidation — closer to honey-green.
Spent leaves (wet leaves): Elastic, whole leaves of light green color with characteristic reddish edges (紅邊, hóngbiān), indicating the degree of oxidation. Leaves unfold quickly (展開速度快), texture is soft and thin (柔薄), with high moisture and transparency.

7. Chemical Composition:

The chemical profile of Jade Oolong is typical for light Taiwanese oolongs with moderate oxidation. Specific indicators vary depending on harvest season, growing elevation, oxidation degree, and processing methods.

Polyphenols (茶多酚): 18–22% of dry mass. Main fraction — catechins (兒茶素): 12–15%, including EGCG (epigallocatechin gallate), EGC, ECG, and EC. Due to moderate oxidation, a significant portion of catechins remains in unoxidized form, providing antioxidant activity close to green teas.
Amino acids: Total content — approximately 2–4% of dry mass. Key component — L-theanine (L-茶氨酸): approximately 1.5–1.6%, due to agrotechnics (shading before harvest) and variety characteristics. L-theanine is the main carrier of sweet and “umami” taste, as well as a neuromodulator promoting α-brain wave generation.
Alkaloids: Caffeine (咖啡鹼) — approximately 2.5% of dry mass (25 mg/g). Theobromine and theophylline — in trace amounts.
Gallic acid (沒食子酸): Approximately 0.8%.
Polysaccharides (茶多糖): 3–4%, participate in forming the “body” of the liquor.
Essential oils and volatile aromatic compounds: It is in this group that the uniqueness of Cui Yu manifests. The varietal aroma (品種香) is due to high content of linalool, geraniol, nerol, and indole — substances characteristic of jasmine, magnolia, and white flower aromas.
Vitamins: C (partially preserved with moderate oxidation), B₁, B₂, PP.
Minerals: Potassium, magnesium, manganese, fluorine, zinc, selenium.
Special feature: The Cui Yu cultivar is often used as raw material for producing GABA-oolong (佳葉龍茶, Jiāyè Lóngchá) through anaerobic fermentation in nitrogen environment, which significantly increases the content of γ-aminobutyric acid (GABA) in leaves. However, standard Jade Oolong does not undergo this treatment and contains GABA at the usual level for oolongs.

8. Health Properties:

The health properties of Jade Oolong are due to its chemical composition, characteristic of light oolongs with high content of preserved catechins and L-theanine:

Antioxidant action: High catechin content (especially EGCG) provides neutralization of free radicals and protection of cells from oxidative stress. In antioxidant activity, light oolongs approach green teas.
Mild tonic effect: The combination of caffeine (~25 mg/g) and L-theanine (~16 mg/g) creates the characteristic “energizing but calm” effect of quality oolongs: improved concentration and cognitive functions without excessive nervous excitement. L-theanine modulates caffeine action, promoting α-brain wave generation.
Digestive support: Moderate polyphenol content stimulates peristalsis and digestive juice secretion. Oolongs are traditionally considered good accompaniment to abundant food.
Cardiovascular system: A number of studies indicate the ability of tea polyphenols to support vascular elasticity and contribute to cholesterol level normalization with regular consumption.
Skin condition: Antioxidants and vitamin C support skin health, slowing aging processes.
Immune strengthening: Catechins possess moderate antimicrobial activity and contribute to immune function support.
Mood improvement: L-theanine has mild anxiolytic action, promoting relaxation without drowsiness.
Oral health: Fluorine and polyphenol content contributes to caries prevention and gum health maintenance.

9. Brewing:

Water temperature: 85–95°C. Lower temperature (85–88°C) emphasizes the floral delicacy of aroma, higher temperature (90–95°C) — reveals taste density and body depth.
Tea amount:
- Flash steeping method (Gongfu Cha / 功夫茶, Gōngfū Chá): 5–7 g per 100–150 ml water.
- Steeping method (European): 3–4 g per 250–300 ml water.
Teaware: Porcelain Gàiwǎn (蓋碗, Gàiwǎn) — optimal choice for revealing the high floral aroma of Cui Yu. Porcelain or clay teapot with thick walls for maintaining stable temperature is also suitable. Yíxīng teapot (宜興紫砂壺) is acceptable but non-functional for light oolongs, as porous clay absorbs delicate aromas.
Process (flash steeping / Gongfu Cha):
1. Warm the gàiwǎn and fairness cup (茶海, Cháhǎi) with boiling water, pour out water.
2. Add dry tea to warmed gaiwan. Inhale the aroma of warmed leaf.
3. Rinse (洗茶, Xǐchá): pour hot water and immediately pour out liquor (3–5 seconds). This steeping “awakens” the leaf and removes tea dust.
4. First steeping: pour water of needed temperature and steep for 45–60 seconds.
5. Subsequent steepings: gradually increase steeping time by 10–20 seconds with each steeping.
6. The tea withstands 5–7 quality steepings with proper raw material, maintaining taste and aroma.
Cold brewing (冷泡茶, Lěng Pàochá): 10–15 g per 1 liter cold water, steep in refrigerator for 6–8 hours. The cold method particularly successfully reveals the sweetness and florality of Cui Yu, minimizing bitterness and astringency.

10. Storage:

Jade Oolong as a light oolong with minimal roasting is sensitive to the main “enemies of tea”: light, moisture, heat, oxygen, and foreign odors.

Container: Airtight, opaque — foil vacuum bag, ceramic or tin container with tight lid.
Conditions: Dry, cool, dark place, away from spices and strongly scented products.
For long-term storage (more than 6 months): Vacuum packaging and refrigerator storage at 0–5°C and low humidity are recommended. Before opening, the package must be brought to room temperature to avoid condensation on the leaf.
Shelf life: In original airtight packaging — up to 2 years. After opening — recommended consumption within 3–6 months.
Note: Unlike dark oolongs and pu-erhs, Jade Oolong is not intended for long-term aging in standard form. However, there is a separate category — aged Jade Oolong (陳年翠玉, Chénnián Cuìyù), which undergoes controlled aging with periodic roasting.

11. Market and Price Range:

Price category: Jade Oolong is positioned as quality everyday tea of the medium price segment. Due to high cultivar yield and possibility of machine harvesting, its cost is significantly lower than high-mountain oolongs from Qingxin Oolong. Approximate retail prices: in Taiwan — 600–1,500 TWD per jin (600 g) for standard quality; competition samples (比賽茶) — significantly more expensive. In Europe — 50–80 €/kg, in USA — 40–60 $/pound for medium quality tea. High-mountain Cui Yu from Alishan can cost 2–3 times more than flatland tea.
Factors affecting cost: Region and growing elevation, harvest season (spring more expensive than autumn), harvest method (manual more expensive than machine), processing degree, presence of competition awards.
How to avoid counterfeits:
- Flavoring: Most frequent problem — use of artificial creamy or floral flavorings. Determined by excessively strong, “chemical” smell of dry leaf, which quickly disappears when rubbed between fingers and does not develop from steeping to steeping. Natural Cui Yu aroma is delicate, “alive,” and persistent.
- Raw material substitution: Selling cheaper varieties of similar rolling under the guise of Jade Oolong. Authenticity guarantee — purchase from verified suppliers and presence of TTES #13, Cuì Yǔ (翠玉) marking, region indication (Nantou / 南投).
- Liquor evaluation: Natural Cui Yu gives clean, clear liquor without turbidity. Characteristic floral aroma unfolds gradually and persists throughout 5–7 steepings. Flavored tea “loses” smell after 2–3 brewings.
- Spent leaves check: In authentic Cui Yu, brewed leaves are whole, elastic, light green with reddish edges. Broken, dark, or non-uniform leaves indicate low quality or substitution.
- Certification: Presence of Taiwanese competition certificates (南投縣茶商公會 — Nantou County Tea Merchants Association), SGS pesticide testing certificates, geographical marking.

12. Recommended Sources:

Authentic Taiwanese producers: Direct purchase from TRES-certified farms in Nantou County (Mingjian, Songbailing), Chiayi County (Alishan), New Taipei (Pinglin). Recommended cooperatives: Mingjian Farmers’ Association (名間鄉農會), Sōngbǎilǐng Tea Production Cooperative (松柏嶺茶葉生產合作社).
Specialized tea shops: Stores with direct relationships with Taiwanese producers and regular quality testing. Preference for shops providing detailed information about harvest season, processing method, and origin.
Online platforms: Taiwanese tea platforms with international shipping: Taiwan Tea Crafts, Floating Leaves Tea, Mountain Tea. International platforms: Mei Leaf, What-Cha, Yunnan Sourcing (Taiwan section).
Quality markers: Presence of SGS pesticide testing certificates, competition awards from Taiwanese tea associations, detailed origin information (specific township, elevation, harvest season), vacuum packaging with production date.
Price guidelines: Suspiciously low prices (below $30/kg) usually indicate low quality or counterfeit. Optimal price-quality ratio — $40–80/kg for standard quality, $80–150/kg for high-mountain or competition-grade tea.

Conclusion

Taiwanese Jade Oolong (Cui Yu) is a tea with a half-century history and aroma lasting seven steepings. Born from an ambitious breeding program and named in honor of maternal love, it unites the scientific precision of modern agronomy with the poetry of ancient tea culture. Its calling card is the bright, clean, “striking” floral aroma of white flowers, which cannot be found in any other Taiwanese cultivar.

Jade Oolong is the ideal starting point for acquaintance with the world of Taiwanese light oolongs. It requires neither high price nor complex rituals: a gaiwan, clean water, and a few minutes of peace are sufficient to reveal its charm. For the experienced connoisseur, this is an honest, technological tea with unmistakably recognizable character. For the beginner, it is a hospitable invitation to a world of aromas impossible to forget.

13. Comparison with other Taiwanese oolongs:

Parameter	Cui Yu (翠玉, TTES No. 13)	Jin Xuan (金萱, TTES No. 12)	Qingxin Oolong (青心烏龍)	Si Ji Chun (四季春)
Breeding	TRES, 1981; father — Tainong 80, mother — Yingzhi Hongxin	TRES, 1981; father — Yingzhi Hongxin, mother — Tainong 8	Traditional, imported from Fujian (Anxi)	Natural mutation, discovered by farmer
Leaf type	Small-leaf, broad-elliptical	Small-leaf, broad-elliptical, thick	Small-leaf, elongated, thin	Small-leaf
Altitude	300–1,400 m	300–1,500 m	Up to 2,500 m (predominantly high-mountain)	Up to 500 m (lowland)
Cultivar aroma	Floral: magnolia, jasmine, betel palm flowers	Creamy, milky, with mango notes	Multifaceted: floral, fruity, honeyed	Floral: wild ginger, jasmine
Taste	Soft, sweet, buttery	Creamy, sweet, full-bodied	Deep, complex, with pronounced huigan	Fresh, light, slightly astringent
Yield	High (~+20% vs. Qingxin)	Very high	Medium	Very high (4 seasons)
Price segment	Mid-range	Mid-range	High (especially high-mountain)	Budget
Best use	Baozhong, light ball-rolled oolong	Light oolong, GABA oolong	High-mountain oolong, Dong Ding	Everyday oolong, beverages

In conclusion

Taiwan Jade Oolong (Cui Yu) is a tea with half a century of history and an aroma that lasts through seven infusions. Born from an ambitious breeding program and named in honor of maternal love, it combines the scientific precision of modern agronomy with the poetics of ancient tea culture. Its calling card is a bright, pure, “penetrating” floral aroma of white flowers, which cannot be found in any other Taiwanese cultivar.

Jade oolong is the ideal starting point for exploring the world of Taiwanese light oolongs. It requires neither high price nor complex rituals: a gaiwan, clean water, and a few minutes of tranquility are enough to reveal its charm. For the experienced connoisseur, it’s an honest, technological tea with an unmistakably recognizable character. For the beginner, it’s a hospitable invitation to a world of unforgettable aromas.