Portable soup was a kind of dehydrated food used in the 18th and 19th centuries. It was a precursor of the later meat extract and bouillon cubes, and of industrially dehydrated food. It is also known as pocket soop or veal glew. It is a cousin of the glace de viande of French cooking. It was long a staple of seamen and explorers, for it would keep for many months or even years. In this context, it was a filling and nutritious dish. Portable soup of less extended vintage was, according to the 1881 Household Cyclopedia,
...exceedingly convenient for private families, for by putting one of the cakes in a saucepan with about a quart of water, and a little salt, a basin of good broth may be made in a few minutes.
Soup was made in the usual way reduced, degreased — or the fat would go rancid — and then reduced repeatedly until it took on the consistency of jelly. Once it was sufficiently gelatinous to hold its form, it was placed on pieces of flannel or unglazed earthenware dishes and rotated regularly to dry it further. This was a seasonal process attempted only in the winter when humidity was low. Once dry, it was wrapped in paper and stored in boxes.
Portable soup is held to have been invented by Mrs Dubois, a London tradeswoman. Together with William Cookworthy, she won a contract to manufacture it for the Royal Navy in 1756.
The naval authoritiesscurvy among their crews. Therefore they allotted a daily ration to each sailor beginning in the 1750s. Captain Cook was convinced of its efficacy and carried it on both his South-Seas voyages.
hoped that portable soup would prevent
Lewis and Clark on their 1804–1806 expedition into the territory of the newly acquired Louisiana Purchase carried portable soup. According to his letter from Fredericktown, Ohio on April 15, 1803, Lewis purchased the soup from Francois Baillet, a cook in Philadelphia. He paid $289.50 for the 193 pounds of portable soup stored in "32 canisters". Lewis carried it with him overland to the embarkation point on the Ohio River.
However, by 1815, with the publication of physician Gilbert Blane's On the Comparative Health of the British Navy from 1779 to 1814, the efficacy of portable soup for promoting the health of sailors was found lacking. Opinion shifted in favor of canned meats, by a process invented in France in 1806.
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