Peak Alum Works Ruins

At this site of an old alum factory, The National Trust and Heron Recreation have put up display boards about the works. Alum is not exactly aluminium, by the way! - but rather potassium aluminium sulphate. Until the 19th century, it was used by the textile industry in the process of dyeing clothes.

In the 16th century, alum was essential in the textile industry as a fixative for dyes. After initially importing it from Italy, the first works were set up in Guisborough. There are many former works along this coastline and Peak Alum Works affords a wonderful insight into the industry.

The extraction process is very interesting. Alum was extracted from quarried shale through a complicated process which took many months — and tonnes of human urine — to complete.

On the subject, the National Trust states: “The process involved extracting then burning huge piles of shale for nine months, before transferring it to leaching pits to extract an aluminium sulphate liquor. This was sent 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, 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.”

If you are on the Cleveland Way between Robin Hood's Bay and Ravenscar then this is impossible to miss. Descriptive information boards tell a fascinating story.