Why does my bread collapse in on itself?

Thanks, Kya, for my very first question!

"How come dad and our stepmum's bread keeps having the top collapse on it. Doesn't matter if they do it in the oven or the bread machine the top always does this funny thing and it makes for interesting bread but it's driving everyone nuts as to why.

They've made adjustments to water, yeast, oil, proofing times and temperatures so we're kind of at a loss."

There are a few reasons why the bread might be collapsing. Bread turning out well is dependent on a number of factors. They include, among other things, proofing/rising time, oven temperature, and baking time. I would say that one of these things might be the issue.

Starting from the proofing, it might be proofing or rising too long. Gluten, the building block of bread, only has a certain capacity for rising. If the bread is allowed to rise too much, it's like trying to put a third story on a house that is only designed for two. There is no support for the additional expansion of the bread. So, one thing you might try, is not letting to dough rise too much. Make sure you are following the directions on whether you are looking for double volume or triple volume. I know you said they had adjusted proofing time, so if they have really worked on that end, it might be one of the following factors.

Oven temperature might be another culprit. When I cook at home, I almost never pay attention to my oven being pre-heated before putting something in it, unless I'm baking. It is uber important to make sure your oven is at the right temperature before putting your bread in. If you aren't really paying attention to the pre-heat step, do. You might also want to check your oven temp with a properly calibrated thermometer to make sure it is actually at the temperature to which you are setting it. If you are baking at 350, but your oven is really only at 320, your bread will have problems. Also, opening your oven to check the bread can diminish your oven temp by as much as a third, causing your bread to be unfinished when your timer goes off, and this can cause your bread to collapse.

The third factor I've listed is baking time, and this can tie directly with the above factor of oven temp. However, it can also include other things like the weight of your loaf, why type of flour you have used, etc. Heavier breads, perhaps made with whole wheat flours, or which are by their nature more dense loaves (read, not fluffy white bread in this), will need a longer bake time at a lower temperature, to make sure that your bread is completely baked. Let's say you have a dense loaf of bread. You bake it at 350 for 35-40 minutes. It might look done on the outside, have a beautiful golden crust, but it may not be done in the very center. It maybe should have baked at 325 for 45-60 minutes, and that might make the difference in whether it stays up or falls. So, if you have been following a recipe, but the temp and time aren't working out, try setting the oven a little bit lower and cooking a little bit longer.

Let me know if any of those suggestions help. :)