Thickness of Crust

under the lid?  Thick hard crust is usually due to too high a temperature for too long under the lid.  Usually the humidity in the oir will soften the crust as it cools - it does here in AZ where we don't even have humidity in the winter:-)

As you can infer from what dabrownman said, using a lower oven temp and reducing the amount of steam will give you a less crusty result. 

So will not pre-heating your DO, although the difference may not be as obvious.

You can also soften your crust after baking by brushing it with some butter. 

You can also put some oil, milk or fat in your dough, which will tend to soften the entire loaf. 

And of course, these things aren't necessarily mutually exclusive so you can try various combinations to get the result you want. 

The longer the crust is in contact with humidity (water vapor) the thicker the crust.   If you have an oven into which you can inject steam, or you get steam by using any one of a number of other home methods (e.g., ice cubes in a metal tray under your baking loaves), or by entrapping water vapor as it comes out from your dough (the Dutch oven method), you will get a thicker crust than if you bake without the water vapor.  

When I bake my sourdough breads initially in a covered Dutch oven with the oven at 500 degrees F, I keep the cover on only for 30 minutes.  The cover is then removed and the loaf left at 450 degrees F for another 25 minutes.  I then remove the loaf to cool before any slicing.  At this point I measure the internal temperature of each loaf to be certain it's at least 195 degrees F.  The crust I get is somewhat thick but sliceable with a sharp bread knife.

If my theory is correct, (1.)  my crusts would be thinner if I took the cover off any time less than 30 minutes and (2.)  my crusts would be thinnest if I never put the cover of the Dutch oven on at all. 

Reading the above posts I was little bit confused as well. What I get out of the oven with the Dutch oven method depends on what type of bread I am baking. The hardest crust I ever got was the Altamura bread because the original recipe calls for one hour bake at high temperature. My last bake of SD with butternut squash had a really very thin and soft crumb although I have used the same temperature and baking time as I do with other breads. Bread with added seeds and oat porridge has also a thinner crust which becomes substantially softer after the loaf cools down. I start baking at 250dC for 5-10 minutes, then go down to 210-220 dC for next 20-25 minutes, removing the lid after 30 minutes and after that baking at 200-205 dC until the crust becomes brown enough. That usually takes 10-15 minutes, sometimes 20 minutes. Thus my baking time is usually from 40-50 minutes. I must say that I never had an "issue" with too hard crust by my measures. 

If I bake in the wood fired oven I start baking at 240-250dC, use some ice cubes to generate some steam and usually bake for 35-40 minutes until the crust is dark enough or when the knocking test on the bottom of the bread shows that the bread is baked. Sometimes I don't get dark brown color simply because the temperature of the oven is too low. This happens usually when I bake two batches in a row. My wood fired oven was planned to be more pizza oven so the walls are relatively thin and thus the accumulation of heat is just enough for baking only two batches of bread. When the temp is not high enough (about 190-210 dC) the crust is definitely softer.

Just to mention one of the experiments from my quest to get less sour SD bread. I baked with instant yeast and the added SD starter was just an add on to the dough and therefore the bulk ferment was much shorter because of added yeast. I baked the same way as any other bread but the crust was so thin and so soft that I was really disappointed just because of so soft and thin crust.  

Happy baking!

Joze