Roasting yancha
How Wuyi rock tea is roasted: charcoal and electric methods, light to full fire, repeated rounds and resting, and what heat does to aroma and keeping.
Where roasting sits in the process#
Yancha is made in two stages. Primary processing turns fresh leaf into 毛茶 (máochá, crude tea). The published 2026 standard, which takes effect on 1 April 2027, wants picked leaf at the workshop within four hours, then sets withering (萎凋, wěidiāo) in sun or warm air at 35–39 °C, the shaking and resting cycles of 做青 (zuòqīng) that drive partial oxidation, fixing (杀青, shāqīng) at 220–300 °C, rolling (揉捻, róuniǎn) and a first drying in two or three passes, the first at 110–150 °C. Refining, 精制 (jīngzhì), follows: sorting out stems and yellow leaves (拣剔, jiǎntī), sieving and grading, and then the roasting proper, 焙火 (bèihuǒ). Roasting is where much of a yancha's final character is set, and where producers differ most.
The craft is listed as national intangible cultural heritage. 武夷岩茶（大红袍）制作技艺 entered the first national list in 2006 as item Ⅷ-63, nominated by Wuyishan City. The listing describes about ten linked procedures and singles out compound withering, judging the leaf and the weather in 做青, and 低温久烘 (dīwēn jiǔhōng), long roasting at low temperature. Named inheritors include 叶启桐 and 陈德华.
Roasting has two jobs. It drives off moisture so the tea keeps; GB/T 18745-2006 caps moisture at 6.5%, and GB/T 18745-2026 raises the cap to 7.0% from April 2027. And it transforms flavour, trading fresh floral and green notes for roasted, fruity, woody and mineral ones. How far a roaster pushes the second job defines the roast level.
123456Key facts#
The three fires#
Practitioners describe roasting as a sequence of "fires". The first, 走水焙 (zǒushuǐbèi, "water-driving roast") or 初焙 (chūbèi), is a fast, hot pass on freshly rolled leaf; in traditional charcoal practice the fire is almost open, and the leaf is spread to cool afterwards so it does not redden or sour. Stems are picked out the next day. A retelling of the master roaster 陈德华 puts the old charcoal first pass at about 700 g per basket, the leaf reaching around 150 °C, losing about half its water in 4–5 minutes. Machines now do most of this step.
After sorting comes the slow work, called 复焙 (fùbèi, re-roasting), 足火 (zúhuǒ) or 炖火 (dùnhuǒ, "simmering fire"). A Wuyishan producer describes charcoal sessions of 6–10 hours, with at least 10 days to two weeks between them; Path of Cha reports 8–12 hour sessions and rests of weeks or months. The same retelling of Chen Dehua gives modern sessions of 4–8 hours, occasionally 20, and notes that most commercial tea is now roasted only once or twice. It cites target moisture of 4–6% in finished tea.
Heat is judged by hand on charcoal, with the back of the hand on the basket, and by setpoint on electric roasters. These are second-hand practice accounts; a producer's own records of rounds, hours and dates are better evidence than any general rule.
810119Light, medium and full fire#
The trade grades roast by 火功 (huǒgōng, degree of fire): 轻火 (qīnghuǒ, light), 中火 (zhōnghuǒ, medium) and 足火 (zúhuǒ, full), with in-between labels such as 中轻火 and 中足火. 足 means "sufficient", not "excessive"; a full roast should not be equated automatically with burnt tea. The published GB/T 18745-2026, effective from 1 April 2027, specifies the three levels in its roasting clause: light fire for 4–8 hours at 100–120 °C, medium for 6–10 hours at 120–130 °C, full for 8 to 12 hours or more at 130–150 °C, with a second or third roast allowed. These are ranges in a recommended standard, not a labelling duty. Early explainers said the roast level would have to be printed on the pack; the published labelling clause says nothing of the kind, so what a producer calls "medium" remains its own judgement.
Laboratory work gives a sense of scale. A Fujian and CAAS study roasted Rougui at 100, 120 and 140 °C for 2 to 10 hours, and tasters preferred either 100 °C for 8–10 hours or 120 °C for 2–4 hours. Qidan roasted at 110 ± 5 °C was sampled every 2 hours for 12; the authors advise no more than 10. Shuixian charcoal-roasted at 120 ± 5 °C scored best at 10 hours. In a multi-round study, Rougui given three 16-hour roasts about 45 days apart scored 88.2 as crude tea, then 90.3, 92.9 and 87.8: the second re-roast was best, and a third went too far.
The laboratory treatments are not all within the stated standard ranges: some last only two hours. Do not merge different experimental schedules into one roast scale. Electric setpoints of 100–150 °C and the 75–100 °C leaf or air temperatures quoted for charcoal practice measure different things.
37121314115What heat does to the leaf#
The clearest measurements come from a 2021 study of four Wuyi cultivars at low, moderate and sufficient roast. Moisture fell sharply, for Rougui from 5.9% to 1.0% and 0.9%. Free amino acids collapsed: theanine in Qizhong went from 5.49 to 1.08 mg/g. Total catechins in Rougui fell from 77.6 to 67.4 mg/g at full roast, while total polyphenols, soluble sugars, thearubigins and theabrownins did not change significantly. The ratio of polyphenols to amino acids therefore rose, the chemical side of the shift from sweet freshness to roasted depth.
Aroma is rebuilt. In Qidan held at 110 °C, 2-methylpyrazine rose from 16.5 to 293.1 µg/kg over 12 hours, 2-ethyl-3,5-dimethylpyrazine appeared only at 12 hours, and Strecker aldehydes such as 3-methylbutanal climbed from 9.2 to 113.6 µg/kg: Maillard and Strecker chemistry. In Rougui, light fire is marked by alcohols and aliphatic aldehydes, moderate fire by Strecker aldehydes, and high fire by nitrogen heterocycles and furans such as furfural. Moderate fire adds roasted, woody and cinnamon notes over rough tea's floral and grassy ones.
One popular claim needs care. Roasting is often said to convert EGCG into its epimer GCG. That is documented for roasted large-leaf yellow tea, but in the 2021 yancha study GCG did not rise with roast degree.
412151617Charcoal and electric roasting#
Charcoal roasting, 炭焙 (tànbèi), uses bamboo baskets, 焙笼 (bèilóng), set over charcoal banked in pits, 焙窟 (bèikū). One producer gives pits of about 50 × 25 cm holding 30–40 kg of charcoal, baskets about 63 cm high and 45 cm across, and trays of about 4 kg of tea. Charcoal is burned until white and covered with ash before tea goes on. In 暗焙 (ànbèi) the embers are fully covered for gentle, even heat that needs more tending; in 明焙 (míngbèi) they are partly exposed, which lasts longer but heats unevenly. It is slow, skilled and hot work.
Electric roasting, 电焙 (diànbèi), uses ovens or drying cabinets with set temperatures. It is precise, repeatable and cheaper, and is used for first drying and for much commercial yancha. Many producers combine the two: one pass through an electric dryer can roughly halve the charcoal time that follows.
Claims for charcoal, such as a distinct 炭火香 (tànhuǒxiāng, charcoal aroma), far-infrared penetration, or roast character that lasts for years while electric roast fades within months, are practice claims and vendor claims. A GC-MS comparison of charcoal and electric yancha exists, but we have not checked its results. On a listing, "charcoal-roasted" is a process claim that tasting cannot strictly confirm.
891011Resting and 退火#
Freshly roasted yancha tastes of the fire: sharp, dry, sometimes bitter-smoky. Producers rest it before release so the fire can recede, a process called 退火 (tuìhuǒ). Practice accounts say the fire fades over one or two months, that good tea is not roasted in summer heat and roasting runs on into October, and that the new season's tea is best drunk after the Mid-Autumn Festival. Heavier roasts are usually rested longer. These are practitioner observations, and no study we found measures what changes during the rest itself.
Two related words describe moisture. 回潮 (huícháo) is moisture regain from the air after roasting or in storage. Taken far enough it leads to 返青 (fǎnqīng, "turning green"): raw, sour or green-astringent notes in stored tea. Lighter roasts are more prone to it. The usual remedy is a gentle 复焙 at low temperature. One practice source says tea at medium-full fire or above rarely turns, and recommends at least medium fire for tea meant to age.
These practice accounts do not establish a universal release calendar. An early listing may describe maocha, an initial roast or a finished style intended for earlier drinking. Ask when the last roast occurred and how the tea was rested; a harvest year alone does not answer either question.
189191411How roast shapes ageing, and what to ask#
Roast level and keeping are linked. Lightly roasted tea holds more floral aroma and more residual moisture, and is more likely to turn in storage. Fully roasted tea is drier and more stable, and much of what is sold as 陈年岩茶 (chénnián yánchá, aged rock tea) began at medium fire or above and was re-roasted from time to time. Changes do continue in storage: in Shuixian stored for different years, 29 of 1,201 measured metabolites tracked storage time closely enough to predict age. See the ageing guide.
English roast labels are not standardised. "Medium", "medium-heavy", "deep baked" and "multiple charcoal roasts" are each vendor's own scale. Useful questions: how many rounds, how many hours, charcoal or electric or both, and when was the last roast? Producers who roast carefully usually know, and several vendors in this database state rounds and hours on the page.
The 2026 standard does not make the roast level a label item, so Chinese and English roast labels alike remain each producer's own. Its time and temperature ranges at least give buyers a shared reference: a producer who sells 足火 tea can be asked whether that meant 130 °C and above. Even then roast will not be comparable in the cup, because cultivar, leaf grade and the roaster's hand still decide what a "medium" tastes like.
19203215Read a workshop schedule in context#
A temperature without its measurement point can mislead. In its Wuyi manufacturing account, Zhongguo mingchazhi (2000, pp. 354–355) specifies a leaf-surface temperature below 40 °C during sun withering, a drum-wall temperature of 260–290 °C during fixation, and dryer inlet air at 120–150 °C during first drying. Those values describe different objects and different stages. They are not three measurements of how hot the tea leaf becomes, or a scale of final roast strength.
The same account separates fresh leaf by selection, cultivar, growing site and batch. It tells the maker to adapt the work to leaf moisture, cultivar, maturity, weather, the outcome of the preceding step and the timing between steps. Its manual shaking-and-resting description gives a working range while emphasizing judgement of the actual leaf. This is a documented craft account from its period, not a universal schedule for every workshop today.
When comparing a producer’s explanation, record the stage, heat source, measurement location, duration and any cooling or resting interval. A number becomes useful when you know what it measures. The condition of the incoming leaf and the result of the previous operation help explain why two skilled makers can use different schedules.
22Roast levels in practice and in the laboratory#
Scroll horizontally to see all columns.
| Level | Character (practice) | Keeping | GB/T 18745-2026 ranges (effective 1 April 2027), and laboratory references |
|---|---|---|---|
| 轻火 qīnghuǒ (light) | Floral, fresh, clear; brighter liquor | Least stable; prone to 返青 | Standard: 4–8 h at 100–120 °C. Light-fire Rougui marked by alcohols and aliphatic aldehydes |
| 中火 zhōnghuǒ (medium) | Fruity, roasted-sweet, cinnamon in Rougui | Moderate | Standard: 6–10 h at 120–130 °C. Strecker aldehydes rise; Rougui panel favoured 100 °C 8–10 h or 120 °C 2–4 h |
| 足火 zúhuǒ (full) | Woody, deep roasted, mineral; darker liquor | Most stable; usual base for aged tea | Standard: 8–12 h or more at 130–150 °C. Pyrazines and furans rise; Rougui catechins 77.6 → 67.4 mg/g |
Sources#
Show all sources 22Show fewer sources
- 王镇恒、王广智主编. 中国名茶志. 中国农业出版社, 2000年12月第1版. ISBN 7-109-06510-3 / 9787109065109.