Sturgeon Isinglass: From Bookmaking to Breweries

From helping Roman performers walk on coals to aiding brewmasters in the fining process of malt liquors, sturgeon and its byproducts have been a versatile component of many trades. Derived from the German verb -Stoeren- meaning "wallow in the mud", sturgeon have assisted the advancement of civilizations dating back to Ancient Egypt in 1500 B.C. Since then, the sturgeon has been a fundamental part of technological advancements in Europe and Asia. Although less common today, the fish is still present and used in field-specific tasks.

Excerpts from early English literature depict the sturgeon as a harmless bottom feeder. The fish was known to swim up stream to spawn where British fishermen would cast nets in order to catch them. The process was not easy as the sturgeon was regarded by the British as a strong swimmer and would often break free from the nets. Records indicate sturgeon could reach up to 450 pounds in the area. Once caught, a sturgeon’s meat was well received across Europe with pickling being the most popular method of preparation. A sturgeon’s caviar paired with bread was also noted as a favorite of Greeks, Turks, and Venetians alike in the 17th century.

Depiction of Sturgeon System of Natural History

A strong argument can be made that a sturgeon’s value is not as a food source but as a key ingredient in countless products. In fact, the most valuable part of a sturgeon is not its meat. Rather, it is its swimming bladder. Also referred to as a sound, a sturgeon’s swimming bladder helps the fish control its buoyancy. The thin-lining membrane is known to be transformed into isinglass. A long process, the harvested bladder goes through a cleaning and drying process that produces a thin film. In most cases, after drying, isinglass could then be heated to sixty degrees Celsius where it would transform into a sticky substance. Over the years, people have found many creative uses for this material such as a base ingredient of glue, a heat resistor, an alcohol purifier, and a protective lining.

Isinglass Drying Technique from Humphrey Jackson

Starting in ancient Egypt, written records indicate the use of isinglass as an adhesive. Isinglass was also readily available to Roman physicians and pharmacologists. The isinglass glue functioned effectively as a wound-sealer. Physicians specifically applied isinglass to deep skull fractures and old wounds that would not close. Perhaps the most surprising use of isinglass during this time period would have to be its use as a heat-resistor. In the Hellenistic era, performers would apply the thin film to their feet where it would be used as a heat resistor. They would then be able to walk across coals neutralizing the heat being transferred.

Furthermore, artists and paper makers also benefit from using isinglass. Primarily used as a medium for painters, isinglass would be applied to improve the luster and/or translucency of the paintings. As for paper makers, isinglass was commonly used as a sizing agent in paper and fabrics. This provided the products with water resistance.

Hundreds of years later, the British found another use for isinglass. This time, it was used in the fining process of alcoholic beverages. In t