Spreading and cooling (tan liang)
Getting the heat out of the leaf immediately after a hot step, because heat that stays in the leaf keeps cooking it after the operator has stopped.
What it is
Every hot operation in tea has a shadow: the leaf leaves the pan, the drum or the steamer carrying enough stored heat and enough surface moisture to keep changing on its own. Spreading and cooling is the deliberate answer — the leaf is tipped out thin, fanned or blown, and turned until it is at room temperature and its moisture has equalised between blade and stem. In a Chinese green tea line it happens after fixation and again after each firing pass. In a Japanese line it happens within seconds of the steamer, where a cooling and de-watering blower is a dedicated machine rather than an interval. It also has a pre-fixation form, tan fang, in which fresh intake is spread for a few hours before the heat goes on so that the whole bed enters fixation at one moisture. What unites all of them is that the leaf is being held still on purpose, and the reason is always the same: an operation that is not stopped cleanly runs on into the next one.
Also transliterated as: tan liang, tanliang, tan fang.
What it does to the leaf
Removes stored heat and surface moisture from leaf between operations, halting residual thermal change and equalising moisture through the leaf before the next step acts on it.
What it does to the cup
Its presence is invisible and its absence is not: leaf packed or rolled while hot develops a stewed, yellowed, slightly sour character, and a green tea that has lost its fresh top note has very often lost it here.
Variants that matter
Ways this step is carried out that produce genuinely different results, rather than regional names for the same thing.
- Tan fang (spreading fresh leaf)
- The pre-fixation form. Fresh intake spread thin for a few hours to even out moisture, deliberately stopping short of a true wither.
- Blower cooling
- Forced air immediately after steaming or drum fixation. Standard on continuous lines, where there is no interval in which leaf could cool by standing.
- Cooling between firing passes
- The rest between mao huo and zu huo, which `processing-staged-drying` covers from the drying side. The same physical operation, scheduled for a different reason.
- Hui chao (returning moisture)
- Letting cooled leaf stand until moisture from the stem migrates back into a case-hardened blade, so the next shaping pass has something pliable to work with.
Where this gets misdescribed
Cooling is read as waiting — the gap in the schedule while the next machine frees up. It is a scheduled operation with a name in every producing language, and in a modern factory it usually has a machine of its own. Describing a process as fixation then rolling, with nothing in between, omits the step that decides whether the fixation actually stopped.
Other steps at the Fixation stage
- Drum fixation — Kill-green in a heated rotating cylinder that leaf passes through continuously, which is how most Chinese green tea is now fixed.
- Kill-green (fixation) — Heating the leaf to stop oxidation — the step that makes green tea green.
- Pan-firing (Chinese fixation) — Fixation by direct contact with a heated wok or drum, which halts oxidation and toasts the leaf at the same time.
- Steaming (Japanese fixation) — Fixation by live steam rather than dry heat — the choice that separates Japanese green tea from Chinese.
Guides covering this step
- What happens when the order is wrong — Almost every fault in tea is a timing fault rather than a technique fault. Here is what each of the common mis-orderings actually produces, and why several of them are invisible on the day and obvious six months later.
- The steps between the steps — Spreading, cooling, resting, turning. Four operations that occupy most of the elapsed time in tea manufacture, have names in every producing language, and are compressed in English writing into the word “then”.
Sources
- TeaHQ editorial synthesis — TeaHQ
This page is TeaHQ’s own synthesis of well-attested production practice. No external technical document stands behind it, so it describes what producers do rather than asserting measured process parameters.