Late 17th-Century Salt-Glaze Tester Ring / Trial Piece Possibly English (Fulham) or German (Rhenish Westerwald), circa 1650 – 1700

A rare survival from the pioneering decades of salt-glazed stoneware, this hand-formed loop embodies the experimental spirit of Europe’s earliest high-temperature potters.

The piece was made not as a vessel, but as a glaze tester—a practical tool used to monitor the behaviour of salt vapour within the kiln. Its twisted ring form allowed the potter to expose every surface to the firing atmosphere, and to lift the object easily in and out of the kiln with tongs. The deliberate indentations and folds across the surface encouraged the glaze to pool and collect, revealing variations in melt and colour under different vapour densities.

The glaze itself is classic early salt glaze: a mottled, orange-peel surface ranging from chestnut brown to buff, achieved by introducing common salt into the kiln at peak temperature. This technique, discovered in Germany in the mid-17th century and introduced to England soon after, revolutionised European ceramics. The rough unglazed base is entirely functional—providing a secure grip and preventing adhesion to the kiln shelf or furniture.

Objects of this type were never intended for sale. They were workshop trials—working artefacts of technological curiosity—made to help the potter read the kiln. Very few were retained; most were discarded after use or recycled as kiln furniture. This example’s survival, complete and stable, offers a tangible connection to the first generation of salt-glaze production, when potters such as John Dwight of Fulham and their Rhenish contemporaries were still mastering the chemistry of vapour glazing.

Dimensions: 10 cm tall

Weight: 361 g

Condition: Excellent for age. Stable with minor surface irregularities and firing flaws typical of early experimental work. No restoration.

Notes: A museum-quality artefact from the birth of salt-glazed stoneware. Comparable to early kiln-test material associated with Fulham and Westerwald workshops. Rarely encountered outside institutional collections.