2 1/4 teaspoons active dry yeast (1 packet, if you roll that way, we use SAF-Instant in the pound blocks)
1 1/2 cups warm water
1 1/2 teaspoons salt
3 cups bread flour or all-purpose flour and a bit more for dusting the bread after rising and the bench. (I am currently experimenting with getting a good rise with fresh ground flour)
Proof the yeast in a large bowl, then stir in the flour and salt, mixing well. Cover, and let stand 6-18 hours.
Turn it out onto a floured surface, and fold a few times, forming a ball. It's often "looser" then I like, so I add in some flour as needed, usually a couple tablespoons.
Form into a ball and place on a sheet of parchment paper, cover and allow to rest for another hour or two.
Preheat a dutch oven to 450F.
Remove lid, lift in bread on parchment, slash with lame, cover. Bake until done, usually around 35 minutes.. should sound solid and hollow when thumped.
Lift out of oven, let stand an hour..
For camping trips, I usually just put all the dry in a ziplock together, when ready, I dump it into a bowl, add water, stir. So far.. never a yeast failure, but it is a possibility doing it this way.
OP: sorry for going off track from hardtack.. my thoughts have always been to be prepared, and to make bread if at all possible. I keep a sourdough starter running, along with a couple friends, at their homes, that runs back to the 1840's.. With that starter, everything else you need to make good edible, not teeth shattering bread, is normal food stuffs. Wheat, Salt, Water, Sugar, Oil.