Around 1761 William Champion, the owner of Warmley brass works, wanted to expand his business and chose the battery mills (known as Bitton Mill) on the River Boyd at Bitton. In order to expand spelter, copper and brass production and find the necessary investment he partnered with Charles Whittuck of Hanham Hall, who owned coal mines in the area, Charles Bragge (later Lord Bathurst) of Cleve Hill, another coal owner, and Norborne Berkeley (later Lord Botetourt) of Stoke Park, M.P. for Gloucestershire and Thomas Goldney.

Although there was a strong domestic market for brass goods, the huge success of the industry in the first half of the eighteenth century was due to the export trade with West Africa. There, local chiefs greatly valued brass, reprocessing some to make ornate art objects. They paid for these and other goods with slaves who were then shipped by the Bristol boats to the plantations of the Caribbean and the southern states of the US – the middle leg of the now notorious “triangular slave trade”. The final leg brought sugar, tobacco, later cotton, and great wealth to the merchants of Bristol.

It was one of a number of mills acquired and converted in the Avon valley that together constituted the largest brass-producing centre in this country during the eighteenth century.

In the Avon Valley, brass was produced from copper ores imported from Cornwall and smelted at Conham and Crew’s Hole, using an innovative design of furnace which allowed local “pitcoal”, rather than charcoal, to be used. The copper was alloyed with crushed ‘calamine’ or zinc ore mined in Mendip, to produce brass.

Bitton Brass Mill was adapted as a “battery” mill, processing cast brass “naps” (flat ingots) from Bristol by a cycle of water-powered hammering and annealing (heating which allows the metal structure to reform).

Brass is an alloy of copper and zinc, made by different procedures since the first millennium BC. The traditional cementation process continued to supply almost all European brass until the early eighteenth century. It involved sealing a combination of calcined zinc ore, copper and charcoal that were heated in circular furnaces to vaporise the zinc ore, which then diffused into the copper to form brass. By the mid 1800s zinc ore alone was used thanks to the new techniques developed by William Champion at Warmley in the 1730s.

The site was purchased by Thomas Bevan in the early 1830s and converted to a paper mill. See Paper Making ->: Paper Making

There are no illustrations of the brass mill at Bitton, but it would have been similar to the brass mill at Saltford which was also used as a ‘battery’ mill.

Skilled immigrant craftsmen were recruited by William Champion from traditional brass making areas of the Continent bringing their valuable expertise. The skills of these men partly account for the growing success of the industry throughout the eighteenth century. Many of their descendants stayed at the local mills and several of their families continue to live in the Avon Valley today, with names such as Buck, Crinks, Craymer, Fray, Frankham, Ollis, Racker and Steger.