First things first. What’s a grain?
The foods we call grains are the seeds of certain members of the grass family. Wheat, barley, oats, rye, rice, corn, sorghum, and millet are all grains.
Each grain has three main components:
(A) The endosperm: the starchy part that would feed a baby plant if the seed were planted and grown; it makes up about 70-75% of the volume of the grain.
(B) The germ: the part of the seed that would grow into a new plant.
(C) The bran: an outer coating to protect the grain.
Next, let’s talk about milling.
While some grains like brown rice are eaten whole, most are milled. Milling crushes the grain into a meal or flour. It also breaks apart the germ, endosperm, and bran, allowing us to choose which parts to include in that flour. For white flour—which is to say, the majority of flour sold today—that means keeping only the starchy endosperm and discarding the fibrous bran and the oily, quick-to-spoil germ. A flour made only of endosperm keeps for a long time and makes good breads and pastries. But it lacks the flavor and nutrients that are in the bran and germ.
This separation is nothing new; people have been removing the bran and germ to make white flour for millennia. Prior to the industrial revolution, the sifting required to separate the bran and endosperm was a laborious process. That’s why white flour was a rarity used only on special occasions. Advances in milling technology during the 19th century made white flour accessible to the masses. Through many rounds of grinding and sifting and refining, modern roller mills produce white flour. In the milling industry, this white flour is often called 75% extraction. In other words, it includes 75% of the original wheat berry—the endosperm—but none of the other 25% that was the bran and germ. White all purpose (AP) flour and white bread flour are both 75% extraction flours.
Since the endosperm lacks much of the nutrition of the grain, white flours are often enriched: they have certain nutrients like vitamins added back in to make up for what was lost when the bran and germ were discarded. In other words, enriched flour undergoes additional processing to make up for what was removed by the earlier processing.
What about whole grain flours, like whole wheat?
Much like how modern brown sugar is made by taking white sugar and mixing molasses in, most whole wheat flour is made by taking white flour and mixing the bran and germ back in. Whole wheat flour must contain endosperm, bran, and germ in the same proportions as the original wheat berry did. Since whole wheat flour has 100% of the original components, this is called 100% extraction. Put another way, that 100% is the “whole” in whole grain. That’s true for all grains: whole wheat, whole rye, you name it. It’s also true for white whole wheat flour—that’s just a regular whole wheat flour made from a paler colored variety of wheat. If you were to mix back in some, but not all, of the bran and germ, you’d get what’s called a “high extraction” flour—a flour that falls between 75% and 100% extraction.
Legally, for a bread to be labeled as “whole wheat,” 100% of the flour used to make it must be whole wheat flour. However, it can still include other ingredients, like sugar or eggs or any of the non-pronounceable ingredients found in many supermarket loaves.
There’s another way to make whole grain flours.
You could just never sift anything out in the first place. It’s much less common. This is what we do at Zingerman’s Bakehouse on our two in-house stone mills. We use our whole grain flours in many of our baked goods, like our olive oil cake made with freshly milled whole grain durum wheat and our vollkornbrot bread made with freshly milled whole grain rye. In other baked goods, we use a mix of whole grain flours and AP or high extraction flours. Our banana breads are made with 60% freshly milled whole grain soft white wheat and 40% AP flour. Our country multigrain bread is made with a mix of freshly milled whole grain rye and spelt along with high extraction Michigan wheat flour.
One challenge to using whole grain and high extraction flours is that the oils from the germ and bran can make them go rancid more quickly. Since we bake with the flours right away the rancidity and short shelf life isn’t a problem. We never remove any part of the grain, so all the vitamins are already there without any enriching. And just like how freshly ground coffee has a ton of aroma and flavor but months-old ground coffee has lost much of its character, our freshly milled grains give an enormous boost to the flavor of our breads and pastries. You really can taste the difference.