Kneading, whether by machine or by hand, is the best way to get to know your dough. Getting the dough to the point where the gluten is developed just right takes practice, but this process doesn't have to be a mystery.
Is your dough too soft? Too firm? Is it sticky or is the dough tacky? Sticky? Tacky? What's the difference? Does your dough feel like a brick? Does it just sit there like a rock or does your dough spring back when stretched?
Even when you follow the recipe, your dough could be too soft or too firm depending on the type of flour used and the amount of humidity in your environment. And despite what the recipe says, you may need to add a bit more flour or water, depending on how your dough feels.
Kneading - Bread Science
Which is why it's important to know your dough. The dough should be soft and tacky (not sticky) and gluten should be well developed.
A well developed dough should be stretchable (elastic) and soft but not sticky. A firm dough, or a very firm dough will not rise well since the loaf will be too dense. This is where would-be bakers become brick masons.
Tacky - dough that is tacky is good dough. Soft and pliable but not sticky. Tacky dough will adhere to your hands, but when pulled off, just a residue is left on the hand. Dough springs back when pressed.
Perfection: Tacky is where you want to be with your dough. A soft, well developed tacky dough will feel good, will rise well, will bake evenly, and the loaf will have a wonderful, soft consistency when cut.
Sticky - dough that is sticky will be too wet. Not sloppy wet, but wet enough that when handled, the dough sticks to your hand and leaves a good bit of dough when pulled off.
Causes: Too much liquid or not enough flour. Add additional flour 2 TBS or 1/4 cup at a time and continue to knead until the dough becomes tacky.
Problems: Dough will rise but will not have enough structure to maintain a nice, tall loaf. May fall during baking or after the loaf is pulled from the oven. May not bake all the way through.
Firm - a firm or very firm dough will be heavey, difficult to knead by hand, or if using a mixer, the flour and other ingredients don't mix well. The dough is not close to tacky and doesn't spring back when pressed or poked.
Causes: Too much flour or other dry ingredients. Add additional water or other liquid a TBS or 2 at a time and continue to knead until the dough becomes tacky.
Problems: Dough will not rise well. Too much flour causes the dough to be too dense, which prevents the yeast from being able to create the gases and lift needed to allow the bread to rise well. Loaf will be dense, thick, heavy and crumbly when baked.
The development of gluten will depend on what type of flour you are using for your bread. White all purpose flour, bleached flour or white bread flour will all develop strong gluten given enough kneading time.
All hybrid red or white whole wheat flours will also develop strong gluten. All refined white flours and red/white whole wheat flour all come from the same source - the whole wheat kernal. Red and white wheat contain higher percentages of protien, which translate to stronger gluten in most cases.
Breads made with red or white whole wheat or white flour will have good elasticity, will stretch well and will rise well as long as the dough is a good dough (soft, tacky and not too firm).
Ancient varieties of wheat such as Kamut (khorasan), spelt, einkorn and emmer all have high protein as well, but the gluten is not as strong. These grains have great flavor, but protiens are different in these varieties of wheat, and although higher, do not translate into stronger gluten. Kamut, spelt and einkorn all make very good bread. Einkorn flour, when kneaded tends to be a bit sticky, so working faster and kneading for a shorter amount of time (3-5 minutes) works better. Emmer does not have very good gluten and loaves tend to be a bit crumbly because gluten strength is fairly weak.
Flours with strong gluten:
All flours below make very good bread.
White all-purpose flour
White Bleached flour
White Bread flour
Hard Red whole wheat flour
Hard White whole wheat flour
Flours with weaker gluten:
Kamut and spelt make good bread and taste exceptional for whole wheat.
Einkorn - (gluten not as strong as Kamut or spelt, but has excellent taste).
Emmer - Not rcommended for bread
Soft White wheat (pastry/cake flour) Not rcommended for bread
Rye - (usually combined with a flour with stronger gluten)