Glossary

If a porous earthenware body containing soluble lime comes into contact with water, a whitish, snow-like efflorescence often appears on the surface after a while. Especially when the ceramic is exposed to the weather (acid rain), this efflorescence can occur more intensely!

 

As soon as a body, that tends to efflorescence, is coated with a glaze that tends to crack (e.g. craquelé glazes or glazes with cadmium frit from the 7960 - 7969 range), these efflorescences can grow through the crack network and leave a snow-like layer on the surface.

 

The reason of the efflorescence has therefore not to be searched in the glaze, but in the body or in the combination of both! If this effect also occurs with your ceramics, we recommend using a different clay with a lower content of soluble lime. Another possible reason is often the use of very old or completely new plaster moulds or plaster boards. A significantly higher bisque firing temperature (above the glaze firing temperature) can also be used to try to remedy this effect, since the soluble lime is transferred into the melt flux.

Tip: If your ceramic ware shows efflorescence, you can try to clean it with vinnegar.