This video for Portable Soup (aka Pocket Soup) from James Townsend popped up in my feed. If you don't know (like I hadn't until I saw the video) Pocket Soup is basically a shelf-stable ultra-reduced stock. It pretty much looks like leather, stores in a tin, but dissolves into boiling water in minutes. In this video on spring soup, James cooks all of his dry goods and foraged greens and only adds the Pocket Soup at the very end.
I'm intrigued enough that I'm now halfway through the process; if it works half-way as well as Townsend suggests in the soup video, I think this will be a really nice addition to camping menus. Using an electric crock-pot, it's dead easy to make. Mostly, I've been letting it cook or steam while I've done nothing. (I haven't started the drying process yet, so I may yet change my mind on exactly how easy it is.)
Sadly, I didn't get the right cut of meat, so I cheated and added gelatin packets. I don't think that will affect things for the worse. (In fact, maybe purified gelatin will make it more shelf stable?)
According to my not-so-rigorous research (i.e. the wikipedia article), it seems to have been stable even in fairly hot climates. But, given that the wiki article seems to be based on historical documents (and I have no idea how faithful to the original recipe James's version is), and it doesn't sound like there is any contemporary examinations of shelf-life of the gelled stock / leather, I am curious about how shelf stable the Pocket Soup will be. In particular, I wonder about temperature and melting the leather chunks into a blob. The wiki article mentioned that one cook rolled the pieces in flour; I'll probably try corn flour. I imagine this will help with any sticking, but not any melting.
One of the things that has me worried is that there is no salt added. When I think of long-term, shelf-stable foods, I usually assume that they have been cured or salted. James's recipe uses no salt in making the leather.
If you have experience with making / using Pocket or Portable Soup, have you noticed any shelf-life problems or temperature problems?
P.S. For anyone who is interested, I'll report back in a few days after my gel has leathered and I've had a chance to try the reconstituted soup.
P.P.S. I'm about to start making the Mushroom Ketchup, mostly so I can get the mushroom powder James uses in the spring soup video. I'll report back with any insights I have on that, too.