I've already discussed elsewhere a number of myths surrounding sourdough. Here are a few more myths, just about the flour you might use for it. (My thanks for some of the information on bran goes to William Alexander and his thoroughly enjoyable book 52 Loaves.)
Myth: Traditionally, most wheat flour was 100% whole wheat.
Not really. In a traditional flour mill, the grinding stones took bran off the kernels in flakes and flattened the germ. The largest pieces were then removed by sifting. So, most traditional wheat flour was closer to what’s available today in the United Kingdom and the rest of Europe as high extraction flour, with somewhat less bran and germ than it started with. In the United States, we can get something similar by blending whole wheat flour and regular bread flour, as I do in my basic sourdough recipe.
Myth: Mixing unbleached bread flour into whole wheat helps the dough rise by increasing gluten.
It helps the dough rise mostly by reducing the relative amount of bran, as bran will cut the gluten strands. It may also increase gluten—but depending on the flour, it could do the opposite! For example, King Arthur’s regular whole wheat flour has a gluten content of 14.0% and its white whole wheat flour has 13.0%, while its unbleached bread flour has only 12.7%. So, mixing the bread flour with either of the whole wheat flours will reduce its gluten—though not enough to worry about.
Myth: For a better rise, you can make high extraction flour from whole wheat by sifting out some bran.
That’s the advice you commonly read, and there are home flour sifters sold just for that purpose. But this really depends on the kind of wheat and how it was milled.
With roller milling, bran is completely removed in large pieces before being added back for whole wheat flour, and much of this bran can be sifted out later. But impact mills shatter the bran into tiny bits, and grinding stones do the same to bran of the harder strains of wheat common today. Most of these bits are no larger than other flour particles, making them impossible to remove.
So, for example, if you run King Arthur White Whole Wheat Flour through a 40‑mesh flour sifter, it won’t remove much bran at all, and it won’t improve your rise. (Yes, I’ve tried it.)
Myth: Stone-ground flour is always superior.
Stone grinding is often used by companies that take pride in their product—but by itself, it doesn’t guarantee high quality. The most tasteless commercial whole wheat flour I’ve ever tried was labeled stone ground.
Part of this depends on how the mill is operated. Any commercial mill can be run hard and fast enough to cook the flour—and then it won’t matter what kind of mill it is. By the same token, any mill can be run more slowly for lower heat and a superior product.
Stone-ground flour, though, does have one indisputable advantage. With most other milling, bran and germ are first separated from the rest of the wheat kernel—then, if whole wheat flour is desired, they’re added back at the end. The amounts replaced are supposed to be about the same as the amounts removed. But at least in the United States, that’s not legally required, and the companies themselves seldom tell you what they’re doing. So, you usually have no way to be sure of the flour’s true content.
With stone grinding, on the other hand, bran and germ are generally not separated out—and in fact, with most modern wheat strains, they can’t be to any great extent. So, you’re much more sure to be getting all or nearly all of the kernel.
