Japanese Stoneware Care: What Porcelain Never Needs
Care differs between stoneware and porcelain for one reason: whether the body absorbs water. That is the whole difference.
Porcelain is fired at 1,300C until the body turns glassy all the way through, so water cannot pass. You simply wash it and put it away. Stoneware is clay fired at 1,100 to 1,250C, which leaves fine gaps in the body. Water gets into those gaps. That is why it needs care.
There is not much to remember. This guide keeps to four things: first use, daily washing, drying, and fixing problems.
The difference in the materials themselves is covered in stoneware vs porcelain, and the nature of porcelain in Japanese porcelain.
Absorbing water decides everything
The body of a stoneware piece has gaps you cannot see. When water gets into them, three things follow.
- Colour goes in Soy sauce and tea soak into the gaps, and the piece slowly darkens
- Odours stay Oil and dashi become hard to get out
- Damp means mould Put a piece away still holding water and black spots appear from the inside
The first of these is welcomed, as keinen bika.
Keinen bika is the idea that a piece grows more beautiful through use and through the passing of years.
Where the Western concept treats this as wear and deterioration, this is a distinctly Japanese value that treats maturing as a virtue. Not a piece that is at its most beautiful on the day you bought it, but a piece that becomes more beautiful the more it is used. The phrase raising a piece comes from this way of thinking.
Japanese culture treats the first as beauty, but the second and third need handling. The response is very simple.
Once, before first use
A piece you have just brought home is first given a medome, a sealing. It fills the gaps with starch, and once done, stains and odours stay out.
- 1. Put the piece in a pot with rice-rinsing water, or water with flour dissolved in it Enough to cover the piece completely. With no rice water to hand, about two tablespoons of flour or potato starch in water works instead
- 2. Simmer on low heat for about 20 minutes A rolling boil knocks the pieces together and chips them, so keep it at a bare simmer
- 3. Turn off the heat and let it cool as it is Taking it out suddenly cracks it through temperature shock. Wait until it cools naturally in the pot
- 4. Wash it and dry it completely All four steps are one process
Sealing is needed for kohiki, yakishime and crazed pieces. Porcelain does not need it. If you are unsure, look at the foot ring underneath: a white, dense body means porcelain, red-brown or grey means stoneware.
Daily washing
Warm water and a soft sponge. That is the whole of it.
| Stoneware | Porcelain | |
|---|---|---|
| Detergent | Sparingly. The body absorbs it | Use it normally |
| Dishwasher | Best avoided | Fine |
| Soaking | Not for long periods | No problem |
| Scourers | No metal scourers | Fine unless gold-decorated |
The reason to go easy on detergent is that the body absorbs it. What it absorbs comes back out as an odour the next time you serve food on it. Use detergent only when the oil is bad, and warm water and a rub will do the rest.
Running the piece under water before you use it keeps stains out. A dry body absorbs, so filling it with water first leaves no room for soy sauce or oil to get in. That is the logic.
Drying decides almost all of it
This is the most important part of caring for stoneware. A piece straight out of the sink still holds water inside the body, however dry it looks.
- Wipe it with a cloth This takes the surface water. It is not the end of the job
- Leave it overnight somewhere with air moving Turning it upside down, foot ring up, is the reliable way
- Then put it away Stack only once it is completely dry
When you are in a hurry, even a few minutes face-down out of direct sun makes a real difference. Simply stopping the habit of washing and shelving straight away means mould almost never appears.
If stains, odours or mould appear
| Symptom | What to do |
|---|---|
| Brown staining | Redo the sealing first. Only if it still bothers you, dilute an oxygen bleach in warm water and use it briefly. Never chlorine bleach |
| Lingering odour | Fill with water, leave overnight, then boil the next day. Absorbed detergent is often the cause |
| Black spots (mould) | Soak in diluted oxygen bleach, rinse well and dry completely. Be thorough about drying from then on |
| Fine lines have appeared | That is crazing, not a crack. Nothing needs doing |
| Something has burned on | Fill with water and leave overnight and it lifts. Do not scrape it off |
Bleach is a last resort. A stoneware body absorbs bleach too. After using it, always change the water and rinse several times, then dry thoroughly.
What not to do
- Stacking and shelving while damp The single biggest cause of mould
- Long soaking The body takes on too much water
- Cold water on a hot piece Sudden temperature change cracks it. This applies to porcelain too
- Metal scourers and abrasives They scratch the glaze surface, and dirt gets in through the scratches
- Gold or silver decoration in the microwave It is metal, so it sparks
Care is also raising a piece
Stoneware settles in colour and gains a sheen the more it is used. Kohiki moves from white toward a soft unbleached tone; yakishime deepens in the colour of the clay. This change is not dirt. It is the time you spent using that piece.
What is actually happening is covered in pottery that grows, and the word for that change in keinen bika. Care is not the work of keeping a piece from changing. It is the work of letting it change beautifully.
Related reading
Know the material
- Stoneware vs Porcelain: How to Tell Them Apart
- Japanese Porcelain: Made from Stone, Not Clay
- Earthenware, Stoneware, Porcelain: The Real Differences
Care and change
- Medome: How to Seal Unglazed Pottery Before First Use
- How to Care for Japanese Ceramics: A Practical Guide
- Crazing (Kannyu): Cracks in Glaze That Aren't Damage
- Pottery That 'Grows': How Ceramics Change With Use
- Keinen Bika: Pottery That Gets Better With Age
Pieces that need care
Pieces available at Nokaze
- Yakishime | Unglazed Japanese Stoneware Fired in Wood Kilns
- Japanese Plates | Handmade Ceramic Plates from Japan
Shop pieces for every day
Care really is only washing and drying. Japanese pottery that settles in colour the more you use it, sent to you directly from the potters who made it.
Browse rice and soup bowlsHow to
Step 1: Run it under water before use
Soak for about 30 seconds, or simply pass it under the tap. A dry body takes up water, so filling it with water first leaves no room for soy sauce or oil to get in. It works best on the pieces that stain most readily, such as kohiki and yakishime.Step 2: Wash in lukewarm water with a soft sponge
Use detergent sparingly, and only when the grease is bad. The body takes up detergent and gives it back as a smell in whatever you serve next. No metal scourers and no abrasives: they scratch the glaze, and dirt enters through the scratches. Avoid long soaking too.Step 3: Wipe it, then stand it upside down overnight
Even when it looks dry, water is still held inside the body. Stand it upside down with the foot uppermost, somewhere with air moving, and leave it for a night. When you are in a hurry, even a few minutes standing upside down in the shade makes a difference.Step 4: Only stack it away once it is completely dry
Stacking pieces away while damp is the single biggest cause of the black spots of mould. Put them on the shelf only once they are dry through. When stacking, a cloth between pieces keeps the glaze from rubbing.
FAQ
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New to Japanese pottery? Start here — its history, how pottery differs from porcelain, the clays and glazes behind each style, and how to care for a piece. → Japanese Pottery: The Complete Guide