Earthenware ceramics are simply plain ceramics, unremarkable and lacking in any distinct personality, in fact, if you were to compare earthenware to food it might be as dull as brown rice without the seasoning. However, its contribution to the world is undeniable. For example, the chances are that the coffee cup sitting on your desk as you read this is earthenware, simply because it occupies the largest area of ceramic production due to its balance of useful characteristics, all available at the right price.
In comparison with porcelain, stoneware and bone china, earthenware contains less glass. As a result, this porous ceramic needs to be covered by a glaze in order to hold liquids. Unlike the vitreous and translucent porcelain or china, earthenware is also opaque. It is not as strong or as dense as bone china or porcelain and is prone to chipping but it does have the advantage of less distortion occurring in the lower firing temperatures and is therefore more stable during processing: another reason why it is so prevalent.
Image: Bowls, Ineke Hans for Royal VKB
•Versatile processing
•Straightforward to form
•Low cost
•More prone to chipping than china or porcelain
•Not as dense or as strong as stoneware
•Fired below 1200ºC (2192ºF) is classed as earthenware
Sources
Widely available.
Cost
A very low-cost ceramic.
Sustainability issues
As an inert material, ceramics do not degrade. In order to produce ceramics an irreversible chemical reaction needs to take place, therefore, unlike thermoplastics, which can be reheated and reused, ceramics are not recyclable in the sense that they cannot be re-moulded. However, they can be crushed and used as fillers and gravel for various industrial applications. The main issue with ceramics is the intense heat that is used during firing, and often, when a ceramic needs glazing, this will involve a second firing process.
Production
Unlike porcelain or bone china, which are perceived as being ‘premium’ materials, earthenware ceramics are more straightforward and easy to process. From high-volume mass production to one-offs they are approachable in terms of both production and cost criteria. As with other ceramics, earthenware can be extruded, slip cast, turned on a lathe and jigger jollied.
Typical applications
It is difficult to narrow down where earthenware is used. It is to ceramics what pine once was to kitchen furniture; used in all product areas, from large sanitary ware to mugs and plates.
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–Versatile processing –Low cost –Stable during processing, unlike some ceramics |
–Prone to chipping –Not recyclable –Energy intensive to produce |