Hardtack is a simple, rock-hard biscuit made from just flour, water, and salt, baked until almost all moisture is gone. Imagine a cracker so tough you'd need to soak it in coffee or soup just to chew it without hurting your teeth. That's hardtack.

For centuries, hardtack was essential food for soldiers and sailors on long journeys because it could last for years without spoiling. During the American Civil War, soldiers on both sides ate hardtack daily, often finding it infested with weevils (small beetles) after months of storage. Sailors called it “ship's biscuit” and would tap their hardtack on the table before eating to knock out any bugs.

Anyone who's bitten into actual hardtack understands immediately why Civil War soldiers joked about it and gave it nicknames like “tooth dullers” and “sheet iron crackers.”

While hardtack kept people alive during wars and sea voyages, very few people ate it by choice. It represented survival, not comfort. Today, hardtack is mostly a historical curiosity, though some outdoor enthusiasts still make it for camping trips where they need food that won't spoil and weighs very little.