Portable Soup

Portable Soup - Bob Spencer
Portable Soup, Too - Bob Spencer
1917 Portable Soup - Kevin Danks
Portable Soup at Kew Gardens - Henk Beentje
Stock for Portable Soup - Jim Klein
Portable Soup in a Vacuum - Satyam
Modern Portable Soup - Janet MacDonald

Portable Soup - Bob Spencer
Surely no collection of recipes could be complete without Stephen's delectable Portable Soup.
The Williamsburg Art of Cookery, 1742.
"Take a Leg of Veal, strip it of the Skin and the Fat, then take all the muscular or fleshy Parts from the Bones; boil this Flesh gently in such a Quantity of Water, and so long a Time, till the Liquor will make a strong Jelly when it is cold: This you may try by taking out a small Spoonful now and then, and letting it cool. Here it is to be supposed, that though it will jelly presently in small Quantities, yet all the Juice of the Meat may not be extracted; however, when you find it very strong, strain the Liquor through a Sieve, and let it settle; then provide a large Stew-pan, with Water, and some China Cups, or glazed Earthenware; fill these Cups with Jelly taken clear from the Settling, and set them in a Stew-pan of Water, and let the Water boil gently till the Jelly becomes as thick as Glue; after which, let them stand to cool, and them turn out the Glue upon a piece of new Flannel, which will draw out the Moisture; turn them once in six or eight Hours, and put them upon a fresh Flannel, and so continue to do till they are quite dry, and keep it in a dry warm Place: This will harden so much, that it will be stiff and hard as Glue in a little Time, and may be carried in the Pocket without Inconvenience. You are to use this by boiling about a Pint of Water, and pouring it upon a Piece of the Glue or Cake, about the Bigness of a small Walnut, and stirring it with a Spoon till the Cake dissolves, which will make very strong good Broth. As for the seasoning Part, every one may add Pepper and Salt as they like it, for there must be nothing of that Kind put among the Veal when you make the Glue, for any Thing of that Sort would make it mouldy. As we have observed above, that there is nothing of Seasoning in this Soup, so there may be always added what you desire, either of Spices or Herbs, noted, that all the Herbs that are used on this Occasion, must be boiled tender in plain Water, and that Water must be used to pour upon the Cake Gravy instead of Simple Water: So may a Dish of good Soup be made without Trouble, only to the above laid Direction: Or if Gravy be wanted for Sauce, double the Quantity may be used that is prescribed for Broth or Soup."
If that won't cure what ails you, it's over the side with you, cannon balls at your feet.

Portable Soup, Too - Bob Spencer
Another name for the stuff is Veal Glue (also Cake Soup, Pocket Soup) and that's appropriate at certain stages. Of course, the method is basically the same as that for making hide glue, the ubiquitous adhesive of days gone by.
I haven't tried the flannel bit, I use a dehydrator, instead.
Whatever, it's worth the effort, as Stephen would assert, and as you can see by the testimonial of William Byrd, Virginia aristocrat, in his The Histories of the Dividing Line Betwixt Virginia and North Carolina, 1729:
"This Glue is so strong, that two or three Drams, disolv'd in boiling water, with a little salt, will make half a Pint of good Broth, and if you shou'd be faint with Fasting or Fatigued, let a small Piece of this Glue melt in you Mouth, and you will find yourself surprisingly refreshed.
"One pound of this Cookery wou'd keep a Man in good Heart above a Month, and is not only nourishing, but likewise very wholesome. Particularly it is good against Fluxes, which Woodsman are very liable to, by lying too near the moist Ground, and guzzling too much cold water. But as it will be only us'd now and then, in Times of Scarcity, when Game is wanting, two Pounds of it will be enough for a Journey of six months.
"But this Broth will be still more heartening if you thicken every Mess with half a Spoonful of Rockahominy, which is nothing but Indian Corn parched without burning, and reduced to Powder . . ."
You can easily see that this is equivalent to our modern bullion. As a correspondent said, portable soup is nothing more than "Glace de Veau" or "Glace de Viande" that has been dried.
On an interesting side note, Lewis and Clark spent more for portable soup to take on the grand trek to the Pacific in 1804 than on any other single item for the Corps of Discovery, about $255, as I recall.
The good Dr. Maturin knew whereof he spoke.

1917 Portable Soup - Kevin Danks
Every lissun knows about portable soup, but how many have tried it?
Not many, I reckon, and even fewer will have made their own. So for the culinary experimenters among us, here is a recipe from the 1917 edition of Camping and Woodcraft by Horace Kephart. I got the Tennessee University Press facsimile reprint (ISBN 0-87049-556-9) for my recent birthday, and very interesting it is too. Anyway, the recipe:
"Take a leg of young beef, veal or venison (old meat will not jelly easily). Pare off every bit of fat and place the lean meat in a large pot. Boil it steadily and gently for seven or eight hours, until the meat is reduced to rags, skimming off, from time to time, the grease that arises. Then pour this strong broth into a large, wide stew-pan, place it over a moderate fire, and let it simmer gently until it comes to a thick jelly. When it gets so thick that there may be danger of scorching it, place the vessel over boiling water, and stir it very frequently until, when cold, it will have the consistency of glue. Cut this substance into small cubes and lay them singly where that can become thoroughly dry. Or, if you prefer, run the jelly into sausage skins and tie up the ends. A cube or thick slice of this glaze, dissolved in hot water, makes an excellent soup. A small piece allowed to melt in one's mouth is strengthening on the march.
This is a very old recipe, being mentioned in Byrd's History of the Dividing Line, and recommended along with rockahominy."
So now you know. He has the recipe for Hudson Bay pemmican as well, which I suspect isn't at all what the Swallows and Amazons had in mind.

Portable Soup at Kew Gardens - Henk Beentje
I was browsing among the new publications at Kew and what do I find - an article on portable soup. With a picture, too, for all love. It looks like a slab of toffee with the broad arrow upon it - maybe 20 cm a side, and 2 cm thick (say, 8 by 8 by 1 inches, for the metrically challenged). There are recipes too, which boil down (ha!) to the following:
"take lean, fresh meat such as beef, trim off all fat; boil over a fire, then simmer, then simmer au bain Marie until the consistency of glue; spread out and cut in slab-sided (ha!) pieces, and let dry some more. To reconstitute, add water, and boil."
There is a block at Greenwich, from which the image was taken; unfortunately, the block is now in several pieces (the author suggests a hungry librarian). The article ends along the lines that it might still be edible, after all these (1776 - now) years; that time is of the essence; and bon appetit!
PPC 76: 83-95 (2004). PPC stands for Petit propos culinaires, but it is nearly all in English.

Stock for Portable Soup - Jim Klein
This is also the recipe for a basic stock - called fond in French - which at the gelatin stage becomes demi-glace if you add tomatoes. Escoffier is the classic reference. He says stock is the essence of French cookery.
We always have some stock on hand. We make it out of turkey, beef, or chicken, but we don't take it to the reduced level Captain Danks mentions. Freeze it, and you've got ten minute gravy with the addition of corn or potato starch. Flavor it with a bit of marmalade or ginger preserves, and they think you're Escoffier's long lost grandson.
It also helps the flavor to add a mirepoix to the stock after you remove and discard the bones and meat.
When I make it for Thanksgiving dinner at the Boat Club we take two frozen turkeys, take off the plastic wrapping, put 'em in the biggest stock pot we have, cover em with water, and boil 'em for 4 or 5 hours. When they get soft, take out the giblets, and the rest of the detritus, and boil 'em for a few more hours. Then strain the mess and throw the meat and bones to the seagulls, reserving the liquid for further reduction. That's gravy when you're done.

Portable Soup in a Vacuum - Satyam
A friend of mine used to do it with a somewhat modified procedure. He was a mountain climber and made some extra money preparing rations for climbing expeditions. He made not only soups but also stews and other dehydrated dishes.
After boiling whatever he meant to make the soup of, chicken, veal, vegetable in a pressure cooker, he opened the cooker, took out the unwanted pieces, added some gelatin powder if needed while everything was still hot and then closed it again. His pressure cooker had a small pipe on the top where the safety valve sat. He took out the safety valve and plugged the hose from a very small vacuum pump. The boiling temperature of water decreases in vacuum to the point where you can get water boiling with the heat of your hands. In very little time all the water would evaporate without further cooking, no stirring needed, no scorching against the bottom. His stews could have plenty of sticky gravy since there was no need to stir them.
For some of his soups, specially vegetable soup, he would just grind the ingredients very fine and cook them lightly and then use the vacuum pump. In this way, he would save many of the nutrients that are otherwise lost with too much cooking. This is the basic process for bullion cubes, though I can't tell what else besides salt and spices is added to that. For some of the rations he kept the fat since, after all, they would be consumed withing weeks of being prepared, in which case the result was a thick paste.

Modern Portable Soup - Janet MacDonald
One of my recent finds in the Victualling Board papers was the original recipe, which I have modified to the modern kitchen and tried, and both of us can assure you that it is extremely tasty and bears no resemblance whatever to glue. I'm putting 'my' recipe in the book, but thought youall'd like a sneak preview:
Portable Soup, a modern version.
This is the author's version of the original recipe, tested and approved by her official taster [i.e. husband]. The quantities given will produce sufficient to reconstitute into four generous bowls of soup. Note that you should not add any salt during the preparation stage, as this will make it difficult to dry the concentrate properly and thus invite deterioration. Salt should not be added until the soup has been reconstituted for immediate eating. Do not be tempted to use a different cut of beef, as shin has generous quantities of the connective tissue which breaks down into jelly.
3 lbs (1.5 k) of beef shin meat, cut into chunks about 1" (2-3 cm) square.
1 lb (500 g) stewing lamb, say neck, chopped into chunks.
8 - 10 sprigs of fresh thyme (or 1 tablespoon of dried)
8 garlic cloves, crushed (or a generous squirt of garlic paste)
16 - 20 black peppercorns, crushed (or several good grindings from a peppermill)
1 teaspoon celery seed (or 6 - 8 stalks of fresh celery, chopped)
At the beginning, you will need two separate saucepans, as cooking the lamb separately will allow easier removal of the fat and also give you the two meats separately to do something else with after straining. The beef will produce virtually no fat.
Put the meat into the saucepans, add cold water until the meat is well covered and bring it to the boil, skimming off the scum as it rises. Then turn the heat down, cover the pans and simmer the meat for twelve hours. Check it at intervals to make sure the meat is still covered with liquid, adding more if necessary. When the meat is done, strain it, keeping the two types of broth separate. You can use this meat to make pies or whatever. Leave the liquid to cool completely, when you can remove the fat which will now have set.
Put the two liquids together in a large saucepan and bring back to the boil. Add the seasonings and simmer for an hour, take the soup off the heat and let it cool a little before putting it through a fine sieve or jelly bag. Press well to get all the juice out and discard the solids. Now put the soup back into the cooking pot, having first wiped out any solid residue and bring it back to simmering temperature, stirring to prevent it sticking, then leave it to simmer, uncovered, for as long as it takes to reduce by three-quarters, checking it at intervals to make sure it hasn't gone too far. Take it off the heat, let it cool for about half an hour before pouring it into a square or rectangular cake tin lined with baking parchment (fold this at the corners rather than cut it, so there are no holes). Leave it to cool completely, cut it into squares, and put these in a very cool oven for several hours to finish drying out. Once dry, wrap each square in parchment and store in a tin until needed. Alternatively, freeze it.
When you need soup, put one or more squares into half a pint of hot water, melt over gentle heat, and add more boiling water to give it a soup density. Now you can add salt before eating it. Toast with toasted cheese on top is not a bad accompaniment!