Strange and unlikely as it may seem the raw material for the manufacture of isinglass is the swim bladders of certain species of fish. The fish use them to control their buoyancy at different depths but it is thought that their usefulness to us may have been discovered by Mediterranean fishermen. They used them to store wine and discovered that cloudy wine emerged from the bladder crystal clear, the ‘cloudiness’ had fallen to the bottom to form a layer from which the clear wine was easily decanted.

Originally Swinbornes were tanners and curriers (leather workers) operating from premises in East Street and at the far end of West Street – where the smelly business of tanning most like took place, well away from the centre of town.  As well as leather,  animal glues were also made, derived from the rendered skins of animals. These glues can be produced in a range of qualities of which the most refined is Gelatine. In 1847 George Swinborne was granted a patent for an improved method of manufacturing it; ‘Improvements in the Manufacture of Gelatinous Substances and in the Apparatus to be Used Therein’. The pure form of gelatine which resulted from this process he called ‘Patent Isinglass‘. This is transparent and has no taste or smell and uses no chemicals in its manufacture. Production was started in part of premises formerly used by the tannery but these were soon extended as demand grew.

Between 1850s and the 1870s there was a huge expansion in the business, and ‘as Thomas Swinborne & Co, Patent Isinglass and Gelatine Refiners and Manufacturers’ more buildings were put up and when the tannery closed in the 1870s its premises were also taken over. Isinglass was widely sold to make jellies and as an ingredient in other domestic foods but it was the production of isinglass for use as ‘finings’ to clarify beer and wine which was responsible for the success of the business. Swinborne’s finings were used in the brewery business throughout the UK and enjoyed a considerable export market especially to the USA.