what is porcelain, anyway?
By Sarah-Linda
There are many terms used to define different sorts of fired objects. Porcelain, ceramics, pottery, stoneware, bone china, earthenware.. so what’s the difference?
As a proud creator and seller of Porcelaine de Limoges, I’d love to explain what that actually means and why it’s important.
The process
The general process of ceramic production goes as follows: a clay body is formed into a shape (by hand, by slipcasting in a mold, dust-pressing or by throwing it on the wheel). After drying, the shape is fired in a kiln a first time at temperatures between 900ºC and 1000ºC, called the biscuit firing.
The shape is now ready to be glazed. Glaze is a mixture of different minerals, creating a vitrified coloured or translucent coating on the surface of the object, making it impermeable and stronger.
After applying the glaze on the biscuit object and letting it dry, it is now fired for a second time, at temperatures between 1000ºC and 1400ºC. The ceramic object is now ready for use. The whole process takes several days to weeks.
Pottery
This is the general term used to refer to all the different ceramic processes altogether.
For each type, the clay varies in composition, and the temperatures vary between 1000ºC and 1400ºC. If you say pottery, you might mean stoneware or earthenware or porcelain. So this is not a very specific term, as it can mean any type of clay body and any firing temperature.
Earthenware
This is the weakest type of ceramic, fired at temperatures between 1000ºC and 1200ºC. It is porous and non vitreous (there was no vitrification of the clay minerals), meaning it can still absorb liquids after firing when unglazed. After glazing it becomes non porous. Because the firing temperatures are relatively low, the material is less strong and more susceptible to breakage. This is the oldest type of ceramic created by humans, dating back all the way to 25.000-29.000 BC. It can also be referred to as terracotta.
Stoneware
This is still quite a broad definition, but refers to clays with a certain composition (including plastic fire clays, kaolin, quartz, feldspar and chamotte) that are fired at temperatures between 1100ºC and 1300ºC. Vitrification can occur, making the objects stronger and non porous, even when unglazed.
The combination of the raw materials and the higher temperatures makes stoneware a high quality material.
Stoneware was produced from 2600 BC in Asia, and from the Middle Ages in Europe. It was a lot harder to produce because of the high temperatures.
Porcelain
My favorite. This is the strongest and most demanding ceramic material of all. The composition is very specific, kaolin being the main ingredient. After firing at temperatures between 1200ºC and 1400ºC, porcelain is vitrified, very hard, white, non porous and translucent (depending on the thickness). The perfect material for delicate and elegant tableware.
Next to high quality tableware, porcelain is also used for electric insulation, bathroom fittings, dental bridges & crowns, tiles and other engineering applications.
The production of porcelain slowly evolved in China around 2000 years ago.
Porcelaine de Limoges
The city of Limoges is the primary porcelain manufacturing city in France. It started in the late 18th century, when sources of kaolin (the main ingredient of porcelain) were found in the area. Today, some of the most prestigious porcelain manufacturers of the world are still in Limoges.
Porcelaine de Limoges stands for high quality, made-in-France products, which is why I’m proud to produce my collections with a manufacturer in Limoges.
Sustainability
The raw materials used for porcelain production are all natural, come straight from the earth and are widely available. During production, there is little waste as all materials can be re-used or recycled into other products for different industries such as construction, roads or other ceramic productions.
Porcelain is also a very durable material with a long life. It is hypoallergenic, being very resistant to mould, germs, bacteria and dust.
All in all, a pretty handsome material!
Become an author too
Would you like to contribute to our journal? Are you an expert on a topic related to anything connecting pleasure with sustainablity and good living? Let us know at info@sarah-linda.com. We look forward to hearing from you!
