It doesn't matter how long you've been baking. It doesn't matter how careful you are in selecting your ingredients. It doesn't matter how careful you are. It doesn't matter where you went to school. It doesn't matter if you're an amateur or a professional. Sooner or later, your bread won't come out the way you want it to. As we tell our 13-year-old son, "Life's not fair. Get used to it."

However, with baking, you can recognize what you don't like and take steps to avoid the same problem happening again. I've divided the troubleshooting sections into sourdough specific and general baking sections. Some tips might be in both places.

A. Sourdough troubleshooting

Symptom	Cause and possible solutions
Rise takes too long	Make sure starter is fully active before using it, use more starter, or rise bread at higher temperature.
Rise was too fast	Use less starter, let bread rise at a lower temperature, consider rising bread in refrigerator.
Loaf didn't rise, though dough did in earlier rise	Make sure you knead the dough before forming the loaf.
Sourdough taste missing, or too weak.	Extend rising time, add rye flour to recipe. Haste is the enemy of good bread.
Sourdough taste too strong.	Reduce rising time, reduce rye flour content of recipe.
Dead starter, starter won't revive, mold on top of the hooch	It's unlikely your starter is beyond hope. In fact, Dr. Ed Wood says that in 50 years of working with sourdough, he has never seen a starter that couldn't be revived. In both cases, the answer is the same, if you want to recover your starter. Pour off the hooch. Scrape off the mold. Take a tablespoon of starter from the middle of the starter layer in your storage starter bottle. Whisk the tablespoon of starter into a cup of water, whisking in lots of air. Then whisk in a cup and a half of white flour. Cover and let sit at 85 to 90 F. The next morning whisk in another cup of water and cup and a half of flour. Repeat this every 12 hours. You should see signs of life in a day or two. If you have excess starter due to this, use it to make biscuits or pizza. If it doesn't revive in a week, then it's time to start, or buy, a new starter – but that shouldn't happen.

B. General baking troubleshooting

Symptom	Cause and possible solutions
Loaf collapses, or falls really flat, may have doughy, gooey streaks in slices.	Bread rose too long, became over-proofed and fragile. Keep a closer eye on your bread next time, when a loaf is over-proofed it will have a stretched look on its surface. If you catch this before baking, you can knead, reform, and re-rise the loaf.
Loaf sags in the middle, slices are soggy to the bite.	Dough was not aerated enough, probably had too much liquid, and did not get enough kneading. Next time, work in more flour as you knead and keep at it longer.
Loaf has good crumb, but tastes damp	Bread not baked long enough. Try putting it in the oven at a slightly lower temperature and let it cook longer.
Loaf rose more on one side than the other	Bread in the wrong position in the oven. Next time place a single loaf in the center of the oven so that uneven heat distribution won't upset the form and shape of the bread while it is baking. Usually if you have several loaves in the oven, evenly spaced, this problem will not occur since the flow of air around the pans will be regular.
Loaf cracked on one side during baking.	This is likely to be a perfectly good loaf, even if it doesn't look perfect. This is something that at times even the best bakers can't prevent.
Bottom and side crusts are pale and soft, you have to saw the bread has to cut it.	Next time remove the bread from the pan and place it on the rack or tiles in the warm oven to brown and crisp the bottom and sides, turning the loaves once, before cooling. (Also, do not ever wrap loaves in plastic before they are thoroughly cooled. This will soften the crust, and can promote mold.)
Bread has mushroomed, with a deep indentation around the bottom.	Loaf broke away from the bottom crust, usually caused by too much dough into too small a pan, putting a free-form loaf into an oven that was too hot at first, causing the bottom to cook too fast and break away. Either way, you'll have an uneven slice, denser at the bottom than the top, but the bread will still be enjoyable.
A free-form loaf spread too much as it was rising.	The dough was too soft. Free-form loaves must be quite firm when shaped. Next time, add more flour, use a ring to contain the dough, or let it rise in a basket.
Top crust separates from the rest of the bread.	This can have a number of causes. The most likely is a poorly formed loaf, allowing oven heat to cause instant aeration when put in the oven. Look at alternate loaf forming techniques. Over-proofing can cause this, so don't let the bread rise quite so long in the future. Too stiff dough, insufficient rising time, or the dough drying out and forming a crust during rising. This can also happen if you freeze the bread to store it for a while.
Large holes in your bread	Dough could have been over-kneaded or the dough rose too long. This is an advantage with certain free-form loaves, particularly French or Italian loaves, but with other breads an even crumb is one of the attributes of good baking. All this is really a matter of taste though, so if you want a strong bread with big holes and a chewy crust, give the dough lots of kneading and a long, slow rise – even two risings.
Circular streaks in your slices	They are usually caused by the rolling and pinching of the dough when you formed the loaf, and your probably pinched the dough too vigorously.
Doughy or small, hard lumps in your bread slices	The original dough was not mixed sufficiently, possibly because it got too stiff to handle. Next time, hold back on the flour so that the dough gets thoroughly mixed, then work in additional flour as you knead.
Loaf has poor shape	There was too much dough in the pan, the load was improperly or poorly shaped, or there was insufficient rising time.
Loaf is too small	Too much salt, not enough yeast or starter, the bread rose at too cool a dough mixture to allow yeast development, too short a rise, dough not kneaded after the last rise and before forming the loaf, or the oven temperature was too high.
Loaf is pale	There was too little sugar in the loaf, or the dough temperature during mixing and rising was too high (so the yeast ate all the sugar before baking, not allowing enough for carmelization during the baking process), or the oven temperature was too low.
Crumb is too tough	Not enough kneading, the bread didn't rise long enough, or it was baked too long.
Crust is too thick	The bread could be over-baked, or the oven temperature was too low, or the rising time was too long so the bread formed a crust as it rose
Crust is too soft, even though it was fine when the bread came out of the oven.	Chances are that the bread was underbaked somewhat and that the crumb was still moist. As the bread cooled, the moisture in the crumb evaporated out, softening the crust. Next time, bake the bread a little longer, maybe until the crumb is about 5 degrees F hotter than last time. (You DID check the bread's internal temperature, didn't you?)
Loaf has streaked texture	Ingredients not fully mixed, or not kneaded enough, or too much flour used in shaping the loaf (the flour used after the rising will not become properly incorporated into the bread).
Bread has a coarse texture	The dough that was too soft, the temperature of the dough during mixing and rising being too high, the rising time was too long, or the baking temperature was too low.
Excessively yeasty flavor	Bread rose too long, the temperature of the dough during mixing and rising too high, or too much yeast.