nope, sounds overcooked to me.

Dang. The recipe called for setting the oven at 200-250 degrees, I set it at 200 but maybe that was still too much. What is this stuff supposed to look like? I can't find a decent photo anywhere to give me a clue.

Dunno, never made it myself, just have the recepit stowed away.

Here's something else you might want to look at for the next attempt.  It comes from "The Medical and Surgical Reporter" Vol. X, p. 439.

One of the neat things about Google Books is that new stuff keeps popping up every day, so even when we think we have a subject researched, it bears keeping an eye on.

"Dessicated Vegetables.

"Vegetables and meats deprived of moisture and submitted to severe pressure, will remain unchanged and preserve their natural tnste for a long period in any climate. A very large business is now carried on in this city in the way of dedicating vegetables for the army and navy, at Nos. 327 and 329 Stanton street, by the New York Dessicating Company— Theo. C. SCHECHILL, Superintendent. About one hundred and fifty persons are employed in the establishment, and the quantity of vegetables dessicated this year will amount to 56,000 baskets tomatoes; 442 tons string beans: 8,000 bushels green peas; 15,000 barrels turnips ; 30,000 barrels carrots; 23,000 heads cabbage; 12,000 barrels potatoes: 20,000 barrels onions; 100 tons parsley, and a moderate quantity of some other vegetables. The vegetables are picked, cleaned, cut up and grated ; they are then dried and deprived entirely of moisture, after which they are formed into flat cakes, under severe hydrostatic pressure. A cake weighing seven pounds contains sufficient vegetables to make forty-two gallons of good soup. They are excellent for sea voyages, and large quantities have been furnished on army contracts for soldiers in the Held and invalids in the national hospitals."

The "severe" pressure is probably worth noting.  It's like the instruction to use steam power in mixing hardtack dough -- an essential step that's not that easy to duplicate with small batches at home in one-off experiments.  It sounds like one should first dry the vegetables and then find some way of pressing them together.  So perhaps you haven't failed, but are just halfway there.  

Thanks Michael. I'll tinker around with them for a bit.

One more hint comes from "The Army Ration" by E.N. Horsford, 1864 (also Google Books).  In discussing the preparation of dried sausage cakes (by which he would intend to replace cattle for the marching ration) he speaks of "dried sausage material... varnished with gelatine derived from scaps of the hides." (p. 25)

Knox Gelatine is made of beef and pork by products and I assume is chemically essentially the same as the material available then.

Based on this and the earlier source, I suspect you could make desiccated veggies by grating your vegetables, then drying them, then compressing them (I wonder if a flower press would work with small batches?), using gelatine as a binder or a "varnish."

A couple other interesting factoids came out of this book (several actually, but these especially struck me):  Horsford discusses making bread from self-rising flour using two canteen halves in the coals as an oven.  In proposing an individual mess kit based on the existing canteen, he describes a contraption of two curved pans locked around the canteen by the fork and spoon -- essentially a variant on the "reenactorism" of strapping a canteen half onto the canteen. (p. 40)

Enjoy!

Horsford was well ahead of his time, and the late 19th century Germans paid attention to his work, too.  If you take the time to intentionally mispell "desiccated" and use a variety of endings, then Googlebooks will give you several dozen more useful hits, including some fascinating information about the process itself.

You may find this quote useful:

"The vegetables are sliced or cut fine, and carefully dried at a low temperature, so that all the fine flavor may be preserved; the potatoes being previously cooked, while the onions and cabbages are dried raw. After all are thoroughly dried, fifty pounds of the desiccated meat, seven pounds of the desiccated onions, thirby pounds of the dried potatoes, and thirteen pounds of the dried cabbage, making in all one hundred pounds, are mixed together intimately, and eight pounds of the mixture placed in a hydraulic press, and with five hundred tons pressure forced into a tablet one foot square and one inch thick. The tablets formed in this way are placed nine in a tin can, and two tin cans in a wooden case. When these tablets are ready for being coated with gelatine they can be cut through the centre, making two tablets of one.

These half tablets measure twelve by six inches, and are a convenient size for packing in the haversacks of the men. Each
half tablet weighs four pounds. They are coated with gelatine
to prevent the absorption of moisture till required for use.
The cost of this food per pound will not exceed forty-
eight cents; one-fourth of a pound twelve cents. It will
hence be seen that this kind of food, when the expenses of
transportation are deducted, will cost less than the ordinary
food."

The above is from a section on a combination meat & veggie ration.

I can stack an awful lot of books on the stuff but I'm pertty sure it will never reach 500 tons. Maybe this is a task beyond me. <sigh>

Thanks for all the help gentlemen.

Mel,

You don't really need five hundred tons of pressure, as an inexpensive arbor press can do the hob, as well as a larger type bench or post vice. A hand fellow with a pair of woodworking screw clamps (Jorgenson var.) could create adequate pressure, too.  If I can compress the tiles with a spatula, well, you can guess the rest.

Postwar America seemed to have a heck of a lot of desiccating plants in major and second tier cities.  Newburgh NY had ten wartime era factories for this purpose, and finding a Sanborn fire insurance map and an older business directory may help locate some of these structures, if they are still around.  One major manufacturer of desiccating equipment existed, and knowing the American penchant for competition, more makers likely existed. Some of the patent information is simply a tease. I'd like to get back down to a patent repository, such as the one in Richmond, and spend some time looking up devices and processes.

I've seen ads and references to individual vegetables (besides potatoes), as well as the mixed vegetables.  Onions seemed to be popular. Someone asked about desiccated sweet potatoes the other day, and although there was much discussion in the 1870s, quality issues existed well into the Great War period.  Desiccated vegetables appear to lose favor around the advent of ice reefers, and fade greatly in the 1920s. I don't know if that is due to home ice boxes, or what.

From reading blurbs about the different manufacturing plants and their products, one thing is clear, and that is the texture of the desiccated mixed vegetables ranged from fine as sawdust to large chunks of plant material.

Ok I think you did a couple of things wrong.

One, I think you over cooked the vegetables during the boiling part of the process.  In order for the vegetables to maintain some integrity you need to under cook them some.  You want them firm before you try to dehydrate them.

Second (and the only way to be sure is with an oven thermometer) you're oven probably over heated.  Most modern ovens get out of whack after a few years of usage.  Next batch you might want to set the oven at a lower temperature (say 175) and cook a little longer.

It is going to take some experimentation.

Looks like we may have some desiccated mixed veggies for an event in June and another round of culinary punishment in July. This should be fun.