Kerstan first trained as a porcelain painter in industry but was more attracted to clay work than decoration and became an apprentice for well-known German potter, Richard Bampi, an exponent of Asian type glazes. Kerstan became fascinated with the Far East and travelled there many times. He built Germany’s first anagama-style (hillside) kiln in the Black Forest. His major contribution to German ceramics is his combination of a relaxed oriental attitude to making with a strong sense for colourful glazes, drawn from his early days as a glaze specialist.

The ‘Kaisergelts’ translates as ‘Kaiser’s yellow’ or ‘Imperial Yellow’ and was, in Chinese Ch’ing Dynasty times restricted for the use of the Emperor. There is a German Kaisergrun glaze (Kaiser green) and this name may be his playful take on an established glaze. ‘Eisenfell’ refers to the iron saturated glaze used beneath the yellow.