Extract of Coffee was an instant coffee that invented during the Civil War toissue to Federal troops. Extract of Coffee was a paste made out of coffee, milk, and sugar. It might be an item that could be handy in the primitive camp.
The recipe is; Mix 1/2 cup of instant coffee crystals (instant espresso is best with Nestles instant dark roast a good alternative) with one can of Condensed milk (Borden's began making condensed milk in 1830 and was one of the companies that made Extract of Coffee during the Civil War). Do not use Evaporated milk. It isn't thick enough, and it doesn't contain sugar.
Place the coffee crystal in a cup or bowl and add a few drop of hot to boiling water to help break down the crystals. Add just enough to break down the crystals (less than a teaspoonful for 1/2 cup of crystals). Then add the condensed milk until the mixture is a paste the consistency of liquid fudge.
In camp one tablespoon of paste in a tin cup of hot water will make you a cup of coffee that was extremely popular with the Federal troops.