40 minutes ago, chromedome said:
It's not that big a deal, really. You know the added flours have no gluten (with the exception of rye, but we can ignore it when it's a small part of the mixture), so you just add a spoonful or two of gluten to make up the difference. If it comes out dense, you add more the next time. Easy-peasey.
Rye and buckwheat add deep, dark flavors; millet, oats and corn add sweetness; and with corn or millet you get a nice golden hue as well. It's a fun way to play, once you've got the basic recipe to behave for you.
And some flavors are enhanced by toasting the grains or the flour. I have a Nutrimill so buy whole grains, toast them, let them cool and then grind medium to fine. Millet develops a wonderful nutty flavor when toasted, so do oats. I bake a lot with spelt and kamut and always toast them.
It's a bit trickier toasting flour because it can go too far. But at lower temps, no more than 250, you can spread a couple of pounds of flour in a sheet pan and toast it for about 30 minutes, stirring half-way through.