Lead Salt Pans
The pans used by the Romans were typically about 90-100cm square by 15cm deep. Excavations have yielded a number of such pans and we even know the names of a few of the Roman saltmakers thanks to inscriptions on some of the lead pans – Viventius, Veluvius and Cunitus. One pan is inscribed “COPI” which could mean it belonged to a Christian bishop – placing this pan in the late Roman period.
Complete Roman salt pans are in the Salt Museum and at the Nantwich Museum. The pan on display at the Salt Museum in Northwich is one of the four found at Northwich in 1864. The Lion Salt Works has three medieval pans found at Bostock near Middlewich in 1986 and also a replica Roman size lead pan which is used for live salt boiling displays.
Lead salt pans were to be used continuously in Cheshire for fifteen centuries and were only replaced with iron pans in the 17th century when economic conditions made it necessary to change from a wood fuel to the much hotter burning coal. Documentary sources record the use of many hundred lead pans at the Cheshire salt towns during the late medieval period.
Medieval pans are without inscription and rectangular. They are also slightly smaller than the Roman pans at about 90cm by 60cm and 13-15 cm deep. Documents of the 16th/17th century tell us the size of the lead pans then in use. Shortly after the Norman conquest, salt pans grew larger. By the 14th century pans, made from sheets of cast lead beaten up at the sides, measured about 170cm x 90cm.
Brine evaporation occurs with the deposit of scale on the hot pan bottom where this is exposed to the fire beneath. If this is allowed to become too thick the lead will overheat and melt. Hence the scale was regularly removed by picking with an iron implement which has left a pick mark on the lead bottom. All the Roman pans show these pick marks as a band down the middle with pick-free zones on either side. This shows that the pans were supported on solid walls about 50cm apart but surprisingly we have been left with no conclusive archaeological evidence of the nature of these substructures.
Lead melts easily and pans would regularly be damaged by overheating. However, it is a readily recyclable metal and the lead from an damaged or unusable salt pan would be melted down and made into a new pan or put to other use.