Porcelain - Miele Dishwasher Care And Maintenance

3.7 Porcelain

Porcelain, the most revered fine ceramic material, consists of approx. 50%
kaolin, 25% quartz and 25% felspar. These components are ground finely
together and mixed with water to produce a moldable material. After
molding, pieces are first dried and then fired at approx. 1650°F. After the
application of glaze, they are fired again, this time at a higher temperature of
approx. 2550°F.
The finished porcelain does not just have a high chemical resistance to all
detergents, cleaners and foodstuffs, it is also extremely hard (harder than
steel). Porcelain also has high heat retention and good sheeting properties.
This combination ensures good drying results.
Porcelain is available either in plain white or decorated to a lesser or greater
extent. The different types of decoration are as follows:
1. In-glaze decoration:
The colored design is applied to the previously glazed item,
which is then fired at temperatures from 2100°F to 2280°F. The
colors then penetrate the re-softened glaze. The glaze then
surrounds the color pigments and thus protects the design. As a
result of this, porcelain with in-glaze decoration is dishwasher-
proof.
2. Under-glaze decoration:
With this version the colored decoration is protected against the
effects of the suds by a layer of glaze. The majority of porcelain
currently on the market with this type of finish is dishwasher-
proof.
3. On-glaze decoration:
Porcelain decorated in this manner has less resistance. The
colored decoration is applied directly on the surface of the
porcelain and fired at a relatively low temperature of approx.
1470°F. Such items are only dishwasher-proof to a very limited
extent.
Note
Gold decoration is always applied on the glaze and is not
dishwasher-proof.
Technical Information
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