Portable soup was a concentrate that made a dried stock similar to a bouillon cube. It was used in the 18th and 19th centuries and was also known as pocket soup or veal glew. It was used by explorers and sailors including the British Navy.
The Lewis and Clark expedition carried 193 pounds of portable soup, but it does not seem to have been very popular with the expedition members. Portable soup seems to date from around 1690 in both France and England.
As with many products from that time period there seems to be a number of ways of making it. Hannah Glasse gives the following recipe for portable soup in her cookbook The Art of Cooking Made Plain and Easy published in 1747.
She suggests that you use two legs of beef, water, anchovies, cloves, mace, black pepper, onions, thyme and marjoram. The mixture then must cook for about 8-9 hours. You then strain the mixture and let cool so you can remove the fat. The jelly is then cooked a second time until it is “very stiff and thick” and put it into cups. The cups are then placed in boiling water being sure no water goes into the cups. The water is boiled until the portable soup is “like stiff glue”. The glue is then put in cloth and kept in a warm place until hard and dry. Soup preserved made like this, could typically last from two to five years.
The following is the complete recipe from her book. It is easier to read if you know that the old s and f were very close in appearance.There is information showing that at times other ingredients such as eggs and assorted vegetables were included in the recipes. Some sources state that 10 gallons of stock produced a small brown rubbery slab about 6 by 12 by 1 inch, with an intense meaty taste.
Here is an English recipe for portable soup from 1861- INGREDIENTS.—2 knuckles of veal, 3 shins of beef, 1 large faggot of herbs, 2 bay-leaves, 2 heads of celery, 3 onions, 3 carrots, 2 blades of mace, 6 cloves, a teaspoonful of salt, sufficient water to cover all the ingredients.
Directions.—Take the marrow from the bones; put all the ingredients in a stock-pot, and simmer slowly for 12 hours, or more, if the meat be not done to rags; strain it off, and put it in a very cool place; take off all the fat, reduce the liquor in a shallow pan, by setting it over a sharp fire, but be particular that it does not burn; boil it fast and uncovered for 8 hours, and keep it stirred. Put it into a deep dish, and set it by for a day. Have ready a stewpan of boiling water, place the dish in it, and keep it boiling; stir occasionally, and when the soup is thick and ropy, it is done. Form it into little cakes by pouring a small quantity on to the bottom of cups or basins; when cold, turn them out on a flannel to dry. Keep them from the air in tin canisters.
As you can see this is a time consuming process, but it does produce a useful product that can be time saving when you are a hurry. Portable soups were also used for the sick, because it was believed that they were very nourishing.