Rye Bread - it's all about the carraway seeds

I've made rye bread in the past, poorly.  It never rose properly and was always too stiff.  Last night, the dough I almost broke my mixer kneading was for two loaves of rye bread.  I made them using the River Cottage Bread Handbook's basic bread recipe.  The recipe calls for 8 cups of flour, so I used 2 cups of white flour, 3 cups of white bread flour, 1 cup of whole wheat bread flour, 1 cup of spelt flour, and 1 cup of rye flour.  I then sprinkled liberally with carraway seeds.  For the liquid, I mixed (rather old) buttermilk with water.  My theory is that buttermilk never goes bad, because it just gets more sour.  I'm sure that in the age of technology and pasteurized milk this is completely erroneous, but I don't care at all. 

I think it was a good idea to use bread flour mixed with the spelt and rye, because bread flour has better or more glutens than regular flour, which is better again than the denser whole wheat, spelt, or rye flours.  Or, in my personal, non-scientific version - bread flour = rise good; flour = rise okay; spelt/whole wheat/rye = rise not so good.  The bread rose nicely and is delicious, which I'm sure is due to the combination of rye flour, carraway seeds, and sour(er) buttermilk.  It has a slight sour flavor that is complex and wonderful, and then the carraway seeds make the flavor richer and bolder.  Toasted with a little cream cheese, it's divine.  Then again, what isn't divine toasted with a little cream cheese on top?