Earthenware, Stoneware, Porcelain: The Real Differences

Is this earthenware or porcelain? Anyone who loves ceramics has probably asked the question at an antique market, an artist's gallery, or a homeware shop. Held in the hand, earthenware and porcelain feel and weigh entirely differently. And yet surprisingly few people can explain precisely what the difference is.

The differences between earthenware, porcelain, and stoneware look complicated at first, but they become very clear once organised around three questions: what it is made from, what temperature it is fired at, and how much water it absorbs. This article explains Japan's three ceramic categories clearly, and covers regions, uses, and care.

The Three Categories of Japanese Ceramics

What Japanese calls simply yakimono or tōjiki divides, strictly speaking, into three main types: earthenware (tōki), porcelain (jiki), and stoneware (sekki). Each has its own appeal, and each is used differently.

Earthenware: The Warmth of Clay, a Plain Expression

Earthenware is also called tsuchimono, "clay things" — pieces formed from clay and fired at a comparatively low temperature. The fired surface is porous, riddled with fine openings, and characteristically slightly rough to the touch.

What makes earthenware appealing is the warmth and weight you feel when you hold it. Applying glaze produces a wide range of colours and expressions. And in the technique called yakishime, where no glaze is used at all, the plain character of the clay itself comes to the front. Bizen and Shigaraki ware are the leading examples.

Earthenware pieces change expression the more they are used. Tea stains and the colours of food seep in gradually — pieces said to "grow" — and long use produces scenery belonging to their owner alone. This culture of enjoying change over time is one of the sensibilities at the base of Japanese ceramic culture.

Porcelain: White, Thin, and Cool

Porcelain is also called ishimono, "stone things" — pieces fired at high temperature from mineral raw materials such as feldspar and quartz. The result is white and hard, strong even when thin.

Porcelain's defining characteristic is its translucency and its air of cleanliness. It can be finished thin enough to let light through, and rings with a clear, metallic note when tapped. Arita ware, Hasami ware, and Kutani ware are among the leading regions.

White porcelain is almost a synonym for the material. It works well with sometsuke, blue underglaze painting, and with overglaze enamel painting in red, blue, and green, lifting fine designs beautifully. Much of the refined ware used in Japanese restaurants is porcelain.

Stoneware: The Ground Between

Stoneware sits between earthenware and porcelain. In Japanese it is called sekki, a somewhat unfamiliar word domestically, though worldwide it is an extremely widely used category for daily tableware — whisky glasses, coffee mugs, and the like.

Because it holds a warmth close to earthenware while combining the density and strength of porcelain, it is an extremely easy material to live with as practical daily tableware.

Differences in Material: What Each Is Made From

The differences in a ceramic's properties turn largely on what it is made from. Raw material connects directly to the finished colour, texture, strength, and absorbency.

Earthenware: Clay as the Main Material

The raw material of earthenware is clay. Its nature differs by region, and that difference becomes the character of each pottery region.

Shigaraki clay contains coarser particles and is characterised by a plain quality. The daidō clay used for Hagi ware is somewhat whitish, and after firing develops the fine cracks called kan'nyū, crazing, where tea and the colours of food penetrate to create distinctive scenery. Mashiko ware clay is a whitish red clay, producing many thick, plain pieces.

Clay is highly plastic — easy to form — so it can be shaped by a wide range of techniques, from wheel throwing to hand building to mould forming.

Porcelain: Ceramic Stone as the Main Material

The raw material of porcelain is a rock called tōseki, ceramic stone. It is crushed to powder, mixed with water, and formed. Feldspar, quartz, and kaolin are the main constituents, and because plasticity is low compared with clay, forming requires skill.

The Izumiyama ceramic stone used for Arita ware was discovered in the early seventeenth century and became the foundation of Japanese porcelain culture. Extraction has declined and other domestic and overseas materials are now used, but the whiteness and translucency of Arita porcelain remain a quality Japan can be proud of.

Stoneware: Materials Between the Two

Stoneware often combines clay with mineral raw materials. Materials high in iron are frequently used, and after firing the colour becomes brown, grey, or blackish. Because it contains a high proportion of glassy constituents, it does not whiten as much as porcelain even at high temperature, but its structure becomes extremely dense.

The shudei red clay of Tokoname ware is one of stoneware's representative materials. Using iron-rich red clay, the shudei teapot for which the region is famous is held to suit green tea especially well.

Differences in Firing Temperature

As important as material is firing temperature. What temperature a piece is fired at changes its properties fundamentally.

Earthenware: About 800–1,200°C

Earthenware is fired at about 800–1,200°C. The low-temperature bisque firing that prepares the body runs around 600–800°C, and the glaze firing generally around 1,100–1,200°C. Because this is lower than porcelain, the body does not vitrify completely and remains porous.

This porous structure is what connects to earthenware's "warmth," "plain expression," and its capacity to grow. It also carries the drawback of absorbing moisture readily.

Porcelain: About 1,200–1,400°C

Porcelain is fired at the very high temperature of about 1,200–1,400°C. This heat vitrifies the body completely, producing a hard, dense structure. Absorption is essentially zero, and the surface is smooth and glossy.

High-temperature firing makes kiln management difficult and calls on a potter's skill and experience. Too low and sintering is incomplete; too high and deformation or uneven colour occur.

Stoneware: About 1,200–1,300°C

Stoneware is fired at about 1,200–1,300°C, close to porcelain. The body sinters nearly to the point of vitrification, absorption is extremely low, and strength is high. It does not, however, have porcelain's translucency.

What the Temperature of the Flame Gives: Colour, Strength, Translucency

The higher the firing temperature, the denser the body and the greater its strength. And when a body sinters completely at high temperature, as porcelain does, it can be made thin enough to transmit light. The warm matte quality of earthenware, the translucency and gloss of porcelain, the powerful density of stoneware — all are expressions born of firing temperature.

Absorption and What It Means for Daily Use

A very practical measure when choosing a piece is absorbency. Whether or not a piece absorbs water connects directly to how easy it is to live with and how much care it needs.

Earthenware: Absorbent

Because earthenware is porous, it absorbs moisture readily. Food pigments — curry, tomato sauce, soy sauce — and odours seep in easily, and leaving liquid standing in a piece for a long time can leave stains or smells.

A piece that has absorbed water can also crack if subjected to sudden temperature change. As for the microwave: it is prohibited where the glaze contains metallic components, and even where it does not, rapid heating requires caution.

That said, if you begin use correctly and continue to care for a piece properly, it can be used for a long time without particular trouble.

Porcelain: Essentially Non-Absorbent

Because porcelain absorbs essentially nothing, food colour and odour do not transfer easily and it is hygienic. It washes easily and dries quickly, so daily use carries little stress. Many pieces are dishwasher-safe, depending on glaze and painting, and it is an easy material to handle.

The coolness when cold food is served on it is another appeal unique to porcelain, and it looks well on a summer table.

Stoneware: Barely Absorbent

Stoneware's absorbency is as low as porcelain's, making it an extremely practical material. It holds the warm atmosphere of earthenware while being nearly as easy to manage as porcelain — an ideal balance for a daily piece.

Its high practicality is why it is so often used in cafés and restaurants. It chips rarely and does not scratch easily even when stacked, which also suits professional use.

Which Needs Seasoning Before First Use

Medome (seasoning) is needed for absorbent earthenware. Medome is the work of filling a piece's fine pores with rice washing water or rice porridge, preventing stains and odours from seeping in.

Before beginning to use new earthenware, the common method is to place rice washing water in a pot, submerge the piece, and simmer on a low heat for 20–30 minutes. The starch fills the fine pores so that stains and smells transfer less easily. Porcelain and stoneware, with their low absorbency, generally need no seasoning and can be used immediately after purchase.

Regions and Ceramic Categories

Japan's traditional pottery regions each have their own character, and each is usually classed as earthenware, porcelain, or stoneware. Please note, however, that within the same region the classification can differ by technique and by maker.

Mainly Earthenware: Bizen, Shigaraki, Hagi, Mashiko, Iga

• Bizen ware, Okayama　Characterised by unglazed yakishime. The expression of the clay and the marks of the flame — yōhen — are beautiful.
• Shigaraki ware, Shiga　A rough clay texture and warmth. One of Japan's oldest kiln sites.
• Hagi ware, Yamaguchi　Characterised by a pale, whitish colouring and crazing. Known for the "seven transformations of Hagi" as it changes with use.
• Mashiko ware, Tochigi　Thick and plain, loved as mingei ware.
• Iga ware, Mie　The rough expression created by wood-kiln flame is its appeal.

Mainly Porcelain: Arita, Hasami, Kutani, Mino (in part)

• Arita ware, Saga　The birthplace of Japanese porcelain. Fine painting on white porcelain.
• Hasami ware, Nagasaki　Rich in simple, modern everyday tableware.
• Kutani ware, Ishikawa　Characterised by overglaze painting vivid in the five colours of red, blue, yellow, purple, and green.
• Mino ware, Gifu　Boasting a diversity of styles. Both porcelain and earthenware are produced.

Mainly Stoneware: Tokoname, Tamba, Echizen

• Tokoname ware, Aichi　The shudei teapot is representative. Unglazed firing using iron-rich red clay.
• Tamba ware, Hyogo　One of the six ancient kilns. Characterised by the sober colouring of iron glaze.
• Echizen ware, Fukui　Plain pieces with naturally settled ash glaze, shaped by the harsh climate of the Japan Sea coast.

Choosing by Dish and by Use

Which suits you depends on what you will serve and where you will use it. Working backwards from use makes choosing far easier.

For Simmered and Soup Dishes: Earthenware and Stoneware

Earthenware and stoneware conduct heat slowly and keep hot food warm for longer. They suit warm dishes — donabe clay pots, chawanmushi cups, deep bowls used in place of soup bowls. Their plain quality also sits well with the homely image of simmered dishes and soups.

For Sashimi and Cold Dishes: Porcelain

Porcelain conducts heat well and holds cold readily. Its clean whiteness also lifts vividly coloured dishes such as sashimi and dressed vegetables beautifully. For seafood and appetiser plates, porcelain's coolness is ideal.

For an Everyday Rice Bowl: Either Works

For a rice bowl used daily, choose by preference and lifestyle. The points below may help.

• If you want it clean and low-effort　Porcelain — no seasoning needed, and often dishwasher-safe.
• If you value the pleasure of growing a piece, and warmth　Earthenware — it gains character the more it is used.
• If you want something light and sturdy　Stoneware — chips rarely and is ideal for daily use.

On choosing a rice bowl itself, How to Choose a Japanese Rice Bowl (Chawan) goes into detail.

How Care Differs by Material

To use a piece for years, care suited to its material is essential. Here are the points to watch for each of the three.

• Caring for earthenware　Perform medome before first using a new piece, simmering it in water with flour or potato starch, or in rice washing water or porridge. Wash as soon as possible after eating and dry it; never leave it soaking. The microwave may be usable if the glaze contains no metal, but beware sudden temperature change. Dishwashers are generally not recommended. Dry thoroughly before storing, since putting a piece away damp invites mould.
• Caring for porcelain　No seasoning is needed; it can be used straight after purchase. Generally dishwasher-safe, though hand washing is recommended for painted or gilded pieces. Many are microwave-safe, though glazes and decoration containing metallic components are not. Because it is hard, impact can cause cracks and chips, so placing cloth or paper between pieces when stacking prevents damage.
• Caring for stoneware　With its low absorbency, seasoning is generally unnecessary. Many pieces are dishwasher-safe. It is sturdy, chips rarely, and is easy to handle in daily use. Teapots such as Tokoname should be rinsed with hot water rather than detergent, leaving the tea compounds to season the pot.

Detailed care procedures are collected in How to Care for Japanese Ceramics: A Practical Guide.

Knowing the Material Makes Choosing a Piece a Pleasure

Organised side by side, the differences between earthenware, porcelain, and stoneware look like this.

In Japanese ceramics, a difference of material changes not only appearance but the feel of use, the dishes a piece suits, and how it must be cared for. The answer to "is this earthenware or porcelain?" carries more meaning than mere classification, because knowing the material lets you see what clay the maker chose, at what temperature, and with what intention they fired it.

When you cannot decide, start by asking what dishes you want to use it for, and whether you want to spend effort growing a piece or use it easily. Working backwards from there, the piece that suits you emerges naturally.

Knowing the material is also standing at the entrance to Japanese ceramic culture. Visiting a region, hearing a maker speak, actually holding and using a piece — that accumulation builds a deeper relationship with the pieces you own. Do use the differences of material as a clue in searching for the one piece that is yours.

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