Salt-glazing is a once-fire technique where common salt is introduced into the kiln chamber at the clay’s maturing temperature. Sodium combines with silica on the ware’s surface, creating a glaze. Depending on the clay used, a more or less strong bumpy orange-peel effect is produced. The technique was developed in 15th-16th century Germany and Rhineland or Rhenish stoneware was made with that method. The term refers not so much to the fuel used to fire the kiln, but to the introduction of salt towards the end of a firing to get a so-called 'salt peel' effect.

Usually done in large wood or gas kilns, salt is introduced into the mature kiln chamber by the pound at the end of a firing. Due to the intense heat, the salt volatilizes and the sodium combines with aluminum oxide and silica oxide in the clay, forming a glaze on any exposed surface of the work. As the salt creates the glaze, pre-application of glazes is unnecessary, although underglaze decoration may be applied to great effect. Sufficient space should be left between individual pieces, so the salt vapor can circulate freely, reaching as much of the work as possible.

The salt kiln should be made from dense, high alumina bricks to resist deterioration from the salt as long as possible. After many uses, a thick layer of salt glaze will form on the surface, virtually fusing the inside of the kiln. This is the natural course of the salt kiln. When the kiln reaches the maturation temperature of the clay (usually in the stoneware range), salt is introduced into the kiln in increments of about half a pound (quarter kilo) into each available port, while the firing continues. Typically a salt-kiln will have two or more salt ports, where the salt, packed in small paper sachets, can be thrown in. Alternatively a long piece of angle iron serves well to dip the salt deep into the ports. It is important to protect yourself from splatters with protective goggles, gloves and mask. The amount of salt thrown into the kiln will depend on the kiln's size, but about 10-14 pounds fine salt should be enough for a medium sized kiln. Less is required if it is an older salt kiln, as salt residue will help to get the desired effect. Moisture added to the salt will also help the conversion, but also increases the amount of smoke.