I have been trying to increase the amount of soluble fibre in my bread. For years now, I have been using ground flax, cooked in water, with about 1/4 unbleached white and the rest stone-ground whole wheat flour (hard) and added gluten (about 6 tablespoons). This makes a good, reasonably light loaf. Last week I decided to try and add oat bran. To compensate, I used unbleached white (hard) instead of whole wheat. For five loaves, I used 2 cups of flax and 1/2 cup of oat bran, cooked slightly with 3 cups of water. The bread was very good, but it was hard to knead, as it remained sticky, no matter that I kneaded in as much flour as I could. Also, it was perhaps a bit too light. It was chewy but still quite soft.
Today, I'm using the same recipe except I've increased the amount of whole wheat, to about half and half.
By the way, I use about 1/4 cup of honey, 4 teaspoons of salt, 3 tablespoons of oil. I use the regular yeast, and I raise a sponge before making and kneading the dough (about 15 minutes, to knead this quantity). The dough rises for about an hour in a warm, moist oven, and then I make the loaves.
Here's my question: How much insoluble fiber is in a cup of hard, stone-ground whole wheat flour? Am I replacing all of the fiber, if I use my 1/2 cup of oat bran in the above recipe (with only white flour)? Is all of the fiber in wheat flour insoluble? Is all of the fiber in oat bran soluble?
Here's another question: I raise my loaves in a slightly warm oven (My oven's a self-clean type, so it holds heat really well.) I often have bigger holes in the top inch of the loaves. If I covered each loaf, would that solve the problem? What would be the best type of cover to use?