Learning when a loaf of bread is done takes some practice, but don't base your judgments on a loaf taken freshly from the oven. These loaves almost always seem soft and underbaked until they have cooled for at least 20 to 30 minutes. Then, if the loaf still seems underdone, you can pop it back in the oven for a few minutes.
Back in the Oven
To bake undercooked bread a bit longer, place it in its original pan and put it back in the oven at the same temperature you previously baked it. Bake the bread for an additional five to 10 minutes, or just until it's golden brown and cooked through. Quick breads, such as pumpkin bread or banana bread, are done when a toothpick inserted in the center comes out clean, with just a few moist crumbs. Yeast breads are done when the tops are golden brown. Tap them and they make a hollow sound. For the true test of doneness, insert a meat thermometer into the center of the loaf. Bake lean breads, such as French bread, to 205 degrees Fahrenheit. Bake rich loaves that contain eggs to 185 to 190 F.
The Type of Bread
Some types of bread fare better when rebaked than others. Rustic breads, such as pizza crust or flatbreads improve when baked again because they're meant to be crisp and chewy. Soft yeast breads can become dry, especially if you've already cut into the loaf, leaving exposed edges. Quick breads generally turn out fine if you bake them again, but don't overdo it, or they'll dry out. If a quick bread fell in the middle because it was undercooked or lacked leavening, rebaking it will not fix this problem.
If you're going to rebake undercooked bread, do so within two hours of removing it from the oven. After this time, bacteria from raw eggs in the bread can begin to multiply. This bacteria may not be killed when you put the bread back in the oven, creating the potential for foodborne illness.
Perfect Every Time
Although you can rebake most types of bread if they're not quite done, it's better to get it right the first time. Use an oven thermometer to make sure your oven temperature is accurate. If your breads are consistently underdone, a faulty oven thermostat may be to blame. Oven temperatures are often off by as much as 50 to 100 F, which can make a big difference in baking. Aluminum pans cook evenly and quickly, while dark metal pans may cause bread to burn. Turn the oven temperature down by 25 F if you use dark metal or glass pans. Bake bread on the middle rack and don't overcrowd the oven. One or two loaves is about all most home ovens can handle at one time. If you removed your bread early because the top was getting too brown, try turning the oven down slightly next time. Lower the rack the bread sits on or place a piece of foil loosely over the bread to slow browning.