It's time to get caught up with all the social studies fun in Trevor's 5th grade classroom! (For those who are new, I'm a former 5th grade teacher. Each week, I teach history in my son's classroom through cooking, art and other hands-on activities.) We've wrapped up Native Americans and moved on to the Age of Exploration. No study of explorers would be complete without trying the primary food they ate during voyages: sea biscuits.
Sea biscuits are basically thick crackers made of flour and salt, baked until they are rock-hard. They do not spoil and thus are excellent for spending months at sea. To eat them, sailors would dip them into coffee, broth or another liquid to soften them sufficiently to eat.
Combine 4 cups flour and 1 tablespoon salt in a bowl. Add up to 1 cup of water to make a dough. Roll the dough out on a floured surface to approximately 1/2" thick. Cut into 1" squares. (The explorers would have had much larger sea biscuits, but a small square is plenty for students to try.)
Use a fork to poke holes in the sea biscuits.
Transfer them to a cookie sheet and bake at 250°F for approximately 1 hour. Turn each sea biscuit over and bake for another 30 minutes. They should barely change color. You are trying to dry them out rather than bake them. Allow them to cool.
If the sea biscuits are done, they are nearly rock hard and can be stored indefinitely. If they are at all soft, bake them again in a very low oven.