New Bread Book and Whitening of the Crust

I got an awesome fathers day gift from my daughter this year. She is going to New York University so she has been running around the Big Apple for a couple of years now. One of her favorite spots to pick up bakery items is Amy's Bread, which sells a book with some of their recipes, and that was my gift :-)

I have been slowly going through it, reading about their general take on the art of baking bread and perusing the recipes trying to decide what to bake first. I've been on a bit of a spelt kick lately, so I decided to start out with the Organic Whole Grain Spelt with Flax and Sesame recipe.

Notice the white streaks on the crust? I have been having a problem with this for a very long time, but it has only shown up intermittently. I have made all sorts of adjustments to my methods, ingredients, and physical baking apparatus to try and figure out the source of the whitening of the crust to no avail. This book may have the answer!!!! In fact, at the end of this very recipe the book states that white streaks can occur due to INSUFFICIENT STEAM. Hallelujah! Definitely makes sense because the results were never consistent... perhaps I'm depending on how quickly I manage to close the oven door after applying the steam or how long my steaming apparatus was preheated? I got very excited after reading this and when I baked this bread, I made a number of adjustments to my steaming method to try and increase the amount of steam that I got. I definitely got more steam than usual, but the bread still has white streaks. Looks like I need to make further improvements. I also bought a large foil roasting pan to try the covered "self steaming" method, but it wouldn't work for this bake, which included two large loaf pans. Has anyone else had this issue? If so, how did you solve it?

Whitening aside, the crumb was quite dense, moist, and had a nice whole grain taste. However, it was also quite sour... almost too much. This is undoubtedly due to the modifications that I made to the recipe. The original recipe called for commercial yeast along with a levain. I've been spurning commercial yeast lately, so I decided to leave it out. However, I left everything else the same. This necessarily meant that the time tables would be stretched out by quite a bit. Also, in the original recipe, the bread is baked on the same day that the final dough is assembled. I said nuts to that! I'm sure that the long retarded proof that I gave it was the main reason for the kick that it had. It is 100% whole grain after all! If I were to do it over again, I would probably bake it on the same day. I may even add commercial yeast. I guess the recipe was written that way for a reason ;-)