A Quick Note About Evidence

Jian Zhan seasoning is one of those subjects where ceramic science, tea chemistry,
collector experience, and seller folklore often become tangled together.

On this page, we use four simple categories:

What Does 养盏 Mean?

In modern Chinese Jian Zhan collecting,
养盏 (yǎng zhǎn)
literally means something close to “nourishing the bowl.”

It describes using and caring for a Jian Zhan over time and watching its
appearance develop.
^[12]
[13]

You may also encounter 养杯 (yǎng bēi), “nourishing the cup,”
but 养盏 is the expression more specifically associated with Jian Zhan.

Not All Rainbow Color Is Seasoning

This is one of the most important things to understand.

A Jian Zhan can show colorful or angle-dependent reflections for several
completely different reasons.

1. Color Created in the Kiln

Jian glaze can contain iron-rich crystals and nanoscale structures formed
during firing. These structures can produce metallic luster, silver,
blue, brown, and angle-dependent optical effects.
^[1]
[2]
[4]

2. Color That Appears Through Use

Modern collectors report that some bowls change in gloss or apparent color
after repeated tea use. This is generally what collectors mean by
养彩 or 七彩光.

The visual phenomenon is widely reported. Its complete materials-science
explanation has not yet been established.

3. Tea Stain and Tea Scale

Tea can also leave persistent organic and mineral-containing deposits
on ceramic surfaces.
^[7]
[8]

A colorful deposit is therefore not automatically proof that the glaze
itself has chemically transformed.

What the Kiln Already Did

Jian glaze develops much of its character before the bowl ever touches tea.

Researchers examining historical hare’s-fur and oil-spot Jian ware
identified iron-rich crystalline phases including the unusual
ε-Fe₂O₃.
^[1]

Experimental Tianmu and Jian-style glaze research has also demonstrated
processes including phase separation, movement of iron-rich material toward
the surface, magnetite and hematite crystal growth, and the formation and
collapse of bubbles.
^[2]

Scattering, diffraction, and interference from very small structures can
contribute to the observed color.

Jian Can Change Color With Viewing Angle

A 2022 study examined excavated Jian sherds with angle-dependent colors
and identified two different mechanisms.
^[3]

One was associated with coherent light scattering from a structure formed
during firing.

The other was thin-film interference associated with a corrosion layer
created during long burial.

That study is especially useful because it shows that thin surface structures
can affect Jian color.

It does not show that a tea-developed surface layer has the
same composition, thickness, or optical behavior.

Yohen: Another Kind of Rainbow

Research on Yohen-type Jian gives us another reason to be careful with the
word “rainbow.”

A 2023 study of a modern Yohen-style Jian glaze made in cooperation with
Sun Jianxing found bright blue structural color associated with nanoscale
phase-separated structures produced through firing.
^[5]

Separately, the Shanghai Institute of Ceramics, Chinese Academy of Sciences,
reported research on the Southern Song Yohen fragment excavated at Lin’an.
Their analysis linked its iridescence to a film-microsphere structure created
as part of its manufacture.
^[6]

What Science Knows About Tea Deposits

Tea can definitely leave chemically complex material on a ceramic surface.

In a 2007 Food Chemistry study, researchers immersed porcelain
surfaces in black tea and allowed the liquid level to fall through evaporation.
They analyzed the stain that developed.
^[7]

The deposit involved oxidized tea polyphenols as well as mineral material
associated with the brewing water.

A follow-up study found that calcium promoted interactions between polyphenol
molecules and that air exposure encouraged additional polymerization.
^[8]

Tea Film Is a Separate Phenomenon

A 2023 Soft Matter study examined the thin shiny film that can
form on the surface of brewed tea itself.
^[9]

Water hardness, dissolved ions, and tea type affected that film.

So What Causes Modern 七彩光?

At present, the most accurate answer is:

We do not yet know the complete mechanism.

Modern Chinese collector sources commonly give two broad explanations.

One proposes that tea-related deposits form a surface layer that changes
the way light is reflected or refracted.

Another proposes that compounds in the tea react chemically with
iron-containing material in the glaze.
^[12]
[13]

These are important because they document how contemporary collectors
understand the phenomenon.

They should not be mistaken for experimental proof.

Does Hot Water “Open the Crystals”?

You will often see advice saying that hot water opens microscopic
“crystal gaps” or pores so tea can enter the glaze.

A modern Chinese collector guide, for example, recommends using boiling
water when opening a new bowl and explains this in terms of opening
crystal gaps.
^[12]

We have not found controlled materials-science research demonstrating
that mechanism.

Jian glaze can contain surface crystals, pits, bubbles, microcracks,
and other microscopic structures, but that is different from proving
that hot water physically “opens” the glaze for seasoning.

Water Chemistry Matters

Water is probably one of the most overlooked variables in collector
seasoning discussions.

Tea research shows that calcium and other dissolved minerals can strongly
affect tea-film and tea-stain chemistry.
^[8]
[9]

Two collectors can therefore use the same tea but expose their bowls
to different mineral environments.

Does the Type of Tea Matter?

It may, but there is no scientifically established tea-to-color chart.

Modern collector advice sometimes claims that one tea produces gold,
another produces blue, or that dark tea necessarily seasons faster.

We have not found controlled Jian-specific research demonstrating
predictable rules like these.

Tea composition varies enormously with cultivar, processing,
oxidation, roast, aging, brewing strength, temperature, and water.

The 2023 tea-film study also showed that green and black teas behaved
differently depending on water conditions.
^[9]

Do Some Glazes Season More Easily?

Modern collector sources commonly report that some strongly crystalline
surfaces develop visible use-related colors more readily than others.
^[13]

Different Jian glazes unquestionably have different surface structures,
so the observation is plausible.

But a proper test would require different glaze types to be exposed to
the same tea, water, temperature, cleaning routine, and number of sessions.

We have not located a published controlled study of that kind.

How We Recommend Seasoning a Jian Zhan

Seasoning Does Not Require a Dirty Cup

Some collectors try to accelerate seasoning by leaving tea in the bowl
for hours, allowing concentrated tea to dry repeatedly, or packing wet
tea leaves against the glaze.

Those methods will certainly increase prolonged tea contact.

They also create conditions that favor ordinary tea-stain formation.
^[7]
[8]

Interestingly, modern Chinese collector advice itself often warns against
allowing heavy tea scale to accumulate and distinguishes it from the
desired appearance of 养彩.
^[12]

Cleaning a Jian Zhan

For ordinary tea use, plain warm water is sufficient and is the
conservative collector-care approach.

FSOC does not recommend routinely using dish soap as part of everyday
Jian Zhan seasoning.

At the same time, we have not found Jian-specific research demonstrating
common claims that a small amount of mild detergent chemically destroys
the fired glaze, dissolves its iron crystals, or permanently “kills”
a Jian Zhan.

Our water-only recommendation is therefore a conservative care practice,
not a claim that soap has been scientifically proven to destroy Jian ware.

Avoid steel wool, metal scrubbers, abrasive powders, bleach,
aggressive cleaners, and harsh scrubbing.

Toothpaste is also sometimes recommended in collector advice.
Toothpaste formulas vary in abrasiveness and are unnecessary for
routine Jian Zhan cleaning.

Preparing a New Jian Zhan: 开盏

Modern collector guides describe numerous “opening” methods.

Some are simple. Others involve boiling water, tea baths, prolonged soaking,
toothpaste, or simmering the bowl.

FSOC has not found scientific evidence showing that a modern high-fired
Jian Zhan requires any complicated treatment before normal use.

We see no need to boil a valuable handmade bowl simply to begin using it.

Can You Season the Outside?

Tea naturally crosses the rim or exterior during use, so the outside glaze
may also experience repeated tea contact.

Some collectors intentionally wipe or pour tea over the exterior.
This is a personal collector practice rather than a requirement.

If you do it, rinse afterwards and allow the exposed foot to dry completely.

What About Accelerated Seasoning?

Long tea baths, concentrated tea, wet tea leaves, and repeated drying
can produce visible surface change faster.

They also make it increasingly difficult to distinguish natural
use-related change from ordinary deposited stain.

Does One Bowl Need One Tea?

There is no scientific requirement to dedicate one Jian Zhan
permanently to one tea.

The main tea-contact area is glazed, unlike an unglazed clay teapot.

If you are deliberately tracking seasoning as an experiment,
however, using one tea and one water source removes variables
and makes the results easier to interpret.

七彩光 Is Not an Authenticity Test

One particularly dangerous claim is that a Jian Zhan must be authentic
because it developed rainbow color.

That is not a reliable test.

Tea-derived deposits are not unique to Jian glaze. Researchers created
persistent tea stains on ordinary porcelain surfaces.
^[7]
[8]

Conversely, authentic Jian glazes vary enormously, and there is no
scientific rule requiring every genuine Jian Zhan to develop dramatic
七彩光.

What If the Color Wipes Away?

If a colorful effect disappears after wiping or cleaning,
at least part of that visible effect depended on a removable surface layer.

That does not tell us exactly what the layer was made of.

Modern collector sources sometimes distinguish temporary colorful
tea scale from the more persistent effect they consider true 养彩.
^[12]

There is not yet a standardized laboratory definition that separates
these collector categories.

Was 养盏 a Song-Dynasty Practice?

Jian bowls absolutely have deep Song-dynasty tea history.

But modern rainbow-seasoning culture should not automatically be
projected backward nearly one thousand years.

Cai Xiang’s eleventh-century Cha Lu praised dark Fujian tea bowls
because the pale tea showed well against them and because their thick bodies
retained heat.
^[10]

The Metropolitan Museum of Art likewise describes Song Jian bowls as
vessels used with whisked tea and identifies hare’s-fur as a glaze effect.
^[11]

We have not located a primary Song-period source describing deliberate
long-term use of a Jian bowl specifically to cultivate 七彩光.

Interestingly, modern Chinese collector literature also acknowledges
that Song tea drinkers did not use the modern concept of 养盏.
^[13]

Common Seasoning Claims: Checked

Track Your Own Bowl

One of the best ways collectors can learn about seasoning is by documenting it.

When beginning with a new bowl, record:

• maker and glaze type
• date regular use began
• tea or teas used
• water source
• approximate number of tea sessions
• cleaning routine
• whether tea is intentionally applied to the exterior

Photograph the bowl in similar lighting and from similar angles.

Angle matters because some Jian optical effects vary with viewing geometry.
^[3]

What Should You Expect?

Maybe a dramatic rainbow.

Maybe a richer shine.

Maybe stronger contrast in the existing crystals.

Maybe a subtle color difference under angled light.

Maybe ordinary tea stain that needs cleaning.

Or perhaps almost no visible change.

None of those outcomes alone proves that a bowl is exceptionally good,
poor, genuine, fake, correctly seasoned, or incorrectly seasoned.

The Best Seasoning Method

After all the ceramic science, tea chemistry, collector terminology,
and competing rainbow theories, the practical advice remains simple.

Drink tea from the cup.

Keep it reasonably clean. Let it dry. Look at it occasionally in good light.
Photograph the changes if you enjoy following them.

The value of 养盏 does not depend on producing a spectacular rainbow.
A handmade bowl gradually acquiring a history of use can be interesting
even if its appearance changes only a little.