Bread dough's second rise, called proofing, softens its yeasty taste and sets it up for oven spring, a rapid increase in carbon dioxide that creates a tighter, denser crumb. Proofing also proves that your yeast is still active. Although less imperative now than when bakers used fresh wild yeasts, the proofing step's effect on the texture of bread makes it indispensable when you bake with finesse.
Shape the dough after the first rise and place it in an oiled loaf pan or form the dough into a ball and place it in a floured proofing basket.
Turn the oven to the warm setting and let it heat with the oven light on for 2 minutes. Turn the oven off.
Cover the loaf pan or proofing basket with plastic wrap and place it on the middle rack. Set a wide pan of hot water in the bottom of the oven in the back and close the oven door.
Proof the dough until it fills the pan or proofing basket to the plastic wrap. The time varies with the bread and the environmental conditions, but expect it to take at least 2 hours.
Touch the tip of your finger into the side of the dough barely enough to leave an impression. If the impression doesn't spring back, the bread is ready to bake.
You can also proof bread in the refrigerator for a tangier taste; this works especially well with sourdough. Place the loaf in the refrigerator and let it sit for about 24 hours before checking ripeness.
If you're in a rush, you can speed-proof the dough in a microwave. Place about 1 cup of hot water in a bowl or glass and microwave it on high for 2 minutes. Place the bread in the microwave with the cup of water and proof it until it doubles in size.