*YES* overnead dough and it becomes chewy and really nasty

no its not actually. the more you kneed the bread, the more elastic the bread becomes (you push down on the bread and the area that you pushed down comes back up). the "chewy" part is because you arnt using enough butter (butter makes bread soft).

yes. kneading will develop gluten which is a protein in flour, which gives dough the elastic property. yeast in the dough stretches out the gluten chains in the dough during the rising phase of bread making. "punching down" the dough allows the gluten chains to shrink back into their original lengths. the gluten is also sticky which makes these chains stick together. kneading forces them together and will make your bread tough if you overwork the dough.

yep certainly is possible to overknead dough, makes it less elasticky so then you end up making crap bread... =)

Yes it is. Parisian style French breads are, in fact, made by pushing that concept to it's limit. Parisian style breads are nothing but water, salt, yeast and flour. Large batches of twenty or more loaves are mixed for around twenty minutes. The reason for this is because it is this long mixing that produces the chewy consistancy and thick hard crust. This is what you don't want with most breads, but for French bread it's perfect. Any kind of "leavened" dough can be overmixed (or kneaded), regardless of what combinations of ingredients are in the mix. Breads leavened with yeast develop air pockets as soon as the yeast begins to feed on the sugars in the flour, and any other sugars, or starches in the mix. As the yeast feads (don't gross out on me), it begins to "pass gas" into the mix which gets trapped in the glutten (caused by the flour and water mixture). The reason we knead bread is to "pop" the larger bubbles of gas, and force them to become smaller. In order for a loaf to rise (from the expanding gas bubbles), it has to have an airtight seal over the entire surface of the loaf. If you continue mixing, or kneading bread for a long period of time, the surface will begin to tear, allowing the gases to escape, and the bread will not rise evenly, or maybe not at all. This is why we usually allow for two risings when making breads at home. The first kneading is to get all the ingredients mixed, and allow the flour and water to form glutten. You may notice that after the first rising, there are usually some pretty big bubbles in the dough. Letting the bread sit for the first rise does two things. First it, allows the yeast to begin feeding, and producing the bubbles that we want for volume. Second, it allows the glutten to "relax", and stretch sloooowly (without tearing) as the yeast bubbles expand. It is because we have allowed the glutted to relax, that we are able to knead it again without tearing the outer skin, and thus eliminate all the large gas bubbles that allow your peanut butter to squirt out of your PB & J. Sometimes we cut the "air tight" skin so the inside of the bread will "burst" out to form those classic french style loaves. That cut is never made until just before the bread goes into the oven. If you cut them and let them sit for several minutes before putting them in the oven, you don't get that "burst" effect, because all of the gasses are escaping before you have a chance to cook it, solidifying the outer glutten, which becomes the crust. The timing of the cutting is for the same reason that you don't want the outer skin tearing earlier in the process. When you overknead, you are also causing the yeast gas bubbles to become smaller, and smaller, which, in turn leads to a denser, and tougher loaf. French bread pushes the kneading time to it's limit. It's supposed to be dense and chewy, with a hard, crunchy crust. But if you mix it any longer that you are supposed to, it's ruined. When that happens, put the dough into a closed bowl in the refrigerator for a few days, and use it for sourdough starter! Seriously. Judging when to stop kneading comes with experience. If your dough tears even a little you are either being too rough, or it's time to stop and let it rest a while. Working dough by hand is actualy a lot easier that with machines. You can feel how it's reacting to your hands. Fortunately it's not a really expensive hobby if you start with basic recipies that don't require expensive ingredients. Don't be afraid to make mistakes. Just do it. Baking is an art that really isn't that hard to master if you aren't afraid of making mistakes, and occasionally throwing food away (or feeding the birds with it).