Alum Mining at Ravenscar
The Yorkshire Coast can seem like a rugged natural landscape created by time and tide. In fact, human history has had a significant impact on the appearance of this beautiful coastline.
Alum is a mineral which was essential in the textile industry as a fixative for dyes. It was used extensively through the 16th century. Originally, it was imported from Italy. However, the supply to Great Britain was cut off during the Reformation. In response Thomas Challoner set up Britain's first Alum works in Guisborough. Thomas recognised that the fossils found around the Yorkshire coast were similar to those found in the Alum quarries of Europe.
As the industry grew, sites along the coast were favoured as access to the shales and subsequent transportation was much easier.
Alum was quarried from shales through a complicated process which took months to complete. The process involved extracting then burning huge piles of shale for 9 months. It was then transferred to leaching pits to extract an aluminium sulphate liquor. This passed along channels to the alum works where human urine was added! At the peak of alum production the industry required 200 tonnes of urine every year. This is equivalent to the produce of 1,000 people!
The demand was such that it was imported from London and Newcastle. Buckets were left on street corners for collection and reportedly public toilets were built in Hull in order to supply the alum works. This unsavoury liquor was left until the alum crystals settled out, ready to be removed.
An intriguing method was employed to judge when the optimum amount of alum had been extracted from the liquor. When it was ready an egg could be floated in the solution.
The last Alum works on the Yorkshire Coast closed in 1871. This was due to the invention of manufacturing synthetic alum in 1855. Subsequently the creation of aniline dyes which contained their own fixative sealed alum's fate.
There are many sites along the Yorkshire Coast which bear evidence of the alum industry. The Ravenscar Alum Works are well preserved. Visitors can wander amongst the remains on the buildings. From the National Trust shop, head down the hill to the left. You'll see signposts guiding you down onto the Cleveland Way. Follow the signs towards the cliff edge. The remains of the alum works make a great sheltered spot for a picnic!