Basic Sourdough with a Rye punch

Yesterday I started a Basic White sourdough and decided to put in some Rye flour because I was doing sourdough reading and I read that in some bakeries in Europe, the bakers add a small amount of Rye flour to the dough to stimulate the fermentation and get a higher oven spring. So I thought I would try it. I used the basic recipe available for printout on my site: http://www.northwestsourdough.com/basicwhite.html

I added 1/2 cup of whole Rye flour instead of the same amount of white flour. The dough was tight and stretchy when I was mixing the dough. But after bulk fermentation, it felt soft and somewhat slack. So I was wondering what would happen.

Well next day I baked up the three loaves and I got a great oven spring. The bread is really very good. It came out sour, crusty, light with an open crust. What more could you ask?
Here is a couple of pictures:

I will try and post the crumb later.

Here is the crumb: