What happened to my bread?

[tamygram]

I've been learning to bake bread for about the last 10 years. I can make good white and wheat sandwich loaves, my cibatta is probably an 8.5 on a scale of 1-10, and my baguettes aren't too bad either. However I have an occasional loaf that just flops. I made a raisin walnut cinnamon swirl bread a few days ago and when people tried it thier eyes bugged out in delight. My friend requested that I make a few loaves for her for Easter, and when I called her today she said it was very heavy and dry!!! :oops: What did I do? The one thing I did do differently from the first to the second time making this bread is I doubled the recipe the first time. This did not fit well in my 4.5 qt. kitchenaid mixer so I had to dump it and finish by hand. On Sat. when making my friends' loaves I wasn't feeling well and didn't want to mess with doing it by hand so I just made the recipe two separate time in my kitchenaid. Could I have over mixed it? Sorry this is so long I tend to ramble. Any help would be great!

[BubbaGourmet]

tamygram;
I am, by no means, the resident baking expert here but it does sound like a classic overmix. The more you work dough the more developed the gluten becomes and the tougher the finished product will be.