The flavor of buckwheat is really intense, so a little goes a long way, and as Chad points out, it has no gluten so contributes even less structure than rye, so too much involvement within a loaf will result in a weakened dough. Chad suggests using not much more than 5% buckwheat flour in your dough lest you run the risk of a flat loaf. I, being a rebel, defied him and added a whopping 7.8%. OK, maybe that's not terribly rebellious. I just had this idea at the last minute, see, as I was mixing up my dough, I thought I might mill up a few grams of the toasted grains and add that to impart a more nutty flavor. And here's why. For this loaf I milled my own flour using Bob's Red Mill whole buckwheat, but the hull has been removed, so the little pyramidical seeds are cream and green colored resulting in a blonde flour. You can indeed find whole buckwheat with the hulls intact, but I didn't have any on hand, so my resolution to what could have been a missing flavor element to my loaf was to toast up fifteen additional grams of the seeds, mill them and add them to the dough. Boy, did this turn out to be a swell idea, because it imparted a gorgeous nuttiness to the handsome loaf.
I used Heartland Mills high-extraction flour, which is called 'Golden Buffalo' in their online store, for this bread for a couple of reasons. First, it weighs in at 90% extraction, and since high-extraction comprises half the total flour weight, I wanted to use it rather than Jovial which is 80% extraction. I thought it would be lovely to have just a little more bran in the bread. Second, while I adore Jovial high-extraction flour its flavor is much more pronounced than Heartland Mills, and I didn't want it to compete with the special and unusual flavor of the buckwheat. I find HM high-extraction to be a little sweeter and Jovial to be a little more resinous in both the nose and the palate, both wonderful attributes, but things that we should take into consideration with regard to the overall bread. I think that Jovial is really well-suited for breads whose main flour has a sweeter profile. At first glance and taste I quickly realized that it was a sound choice.
Have a look.
(Use the rest of your crème fraîche in the cake that I developed for my friends at Community Grains. It's listed here on Farm to Table Geek, my other blog, and here at Community Grains. Seriously. It's the best cake you will ever make).