The earliest written documentation on "portable soup" goes back to the late 1500s. It's described as somewhat akin to a bouillon cube, with more gelatin. In a 12-hour process, meat and bones were boiled, the solids picked out, and the liquid was boiled further to reduce it to the smallest size possible and the texture of a dried gummi. The result is mostly protein and flavor, perfect for travelers. Ships that explored new continents took portable soup with them. It could be reconstituted with boiling water as a soup base, or added to oats or other available grains. It could also be chewed by itself. Lewis and Clark took 193 pounds of portable soup with them on their exploration of the American West, and instructions for making it appeared in cookbooks up until the 19th century. Other methods of preserving food eventually made portable soup unnecessary, but Britain’s National Maritime Museum has a cake of portable soup from the 1700s. It doesn't look much different than it would have back then, but no one has tried eating it. Read about portable soup at Atlas Obscura.