One bag of masa harina, a dream, and a hot pan is all you need to make a big stack of delicious corn tortillas. To keep your tortillas from being as crumbly as an old bag of grocery store ones, there's one important aspect: hydration.

If your tortillas are expertly made and your masa is well-hydrated, the tortillas will puff up when you cook them. The appropriate hydration level for tortilla masa is 1.2 to 1.3 liters of water per kilogram of masa harina, or a ratio of 1.2 ounces of water to 1 ounce of masa harina.

When you add the appropriate amount of water to your dough, your masa will start out sticky because the flour hasn't absorbed it yet. To rehydrate each grain of dried, ground corn, your masa needs to be kneaded and rested to coax the tough grains of corn flour to hydrate and soften.