Design Dinosaurs / 7: The enamel mug

IN 1856, Bessemer-Siemens invented a process for producing mild steel which could be rolled into sheets. Soon after, lightweight mugs began to be stamped from discs of the new soft steel, and to replace the hefty cast-iron hollow-ware of previous centuries. The sharp top edges were turned over into user-friendly rims; the handles, folded from smaller rectangles of steel, were attached in loops by soldering or brazing. The resulting beakers were then dipped into vats of enamel - hence all the dribbles and blobs - and fired at a high temperature so that the coating fused to the metal in a vitreous layer, leaving a porcelain finish, typically white with blue rims.

The first British patent for enamelling was taken out in 1799, but as the process required lead, antimony and arsenic it wasn't ideal for cooking vessels. In the 1840s, however, spurred by the need to supply ships' galleys with sturdy pots and pans which would not rust in the sea air, Thomas and Charles Clark of Wolverhampton succeeded in producing a lead-free enamel coating which was safe for food and drink.

The pressed steel mug was an obvious candidate for the enamelling process and became instantly popular. It was easy to clean. It left no metallic after-taste. Its lightness and unbreakability made it suitable for outdoor - and military - use, and in the First World War many hollow-ware manufacturers went into government contracts for supplies for the armed services. The mug was so superior to anything else available that people overlooked its deficiencies: the fact that the conductivity of the metal ensured that a hot drink would not only burn both your lips and your fingers but also be stone cold within minutes; and the enamel chipped like glass.

Mystifyingly, the same enamel mug, usually imported from Eastern Europe or China but unaltered in design since the 1860s, still sells relatively briskly in camping shops, for anything from 80p to pounds 2.70; and, until a modern alternative appears which offers a similarly comforting sense of metallic robustness, will presumably continue to do so.