The Mill

By the end of the nineteenth century, our country’s landscape, once rich with local water-powered stone mills and regional grain growing was transformed. Stone milling, the method of milling used for thousands of years, had been practically abandoned. In its place: the roller mill, which processed grain to flour with speed and efficiency, producing a flour whiter than anyone had ever seen prior to this, with an appealing, powdery texture.

This is the flour we are all familiar with, the flour that dominates grocery store shelves and most bakeries. It is a different flour from what is produced on a stone mill. Roller milling separates the three components of the grain: the endosperm, the germ, and the bran. Steel rollers slice away the oily germ and peel off the bran, producing a white, endosperm-only flour with a long, stable shelf life. Stone milling crushes the intact grain between stones, and although the larger bran particles can be sifted out, the oily germ is spread into the starchy endosperm flour, resulting in an off-white or cream-colored flour rich in flavor and nutrients, but with a limited shelf life, as it is the oils in the germ that limit the shelf life. The roller mill’s speed and efficiency and the longer shelf life of the resulting flour were the mainsprings for the centralization and vertical integration of the growing and processing of grain to flour, transforming the Great Plain states into the modern US breadbasket.

Speed, efficiency, and the assumed availability of cheap fuel superseded local fresh flour, nutrients, and flavor. But the local grains movement has reclaimed this part of our past. The reintroduction of stone milling, the oldest technology used to turn grain into flour, has appeared hand in hand with regional grain efforts. And cold stone milling, a method that ensures the temperature of the resulting flour stays well below 100°F, thus protecting the oils in the flour, has elevated the process.

For us, the choice of stone over steel to process our grain into flour was a given, as cold stone milling produces flavor-forward flours that highlight the terroir of our region. This is part of the story we seek to tell—flavorful flours of geographic distinction. This flour is a different product. Roller milling is incredibly efficient, but it strips flavor and nutrients from the resulting flour, and although flavor can be conjured out of any flour through the process of slow fermentation, cold-stone-milled flour offers the baker a whole new palate of flavor and tooth to engage with—whether applied to slow ferments, straight doughs, pastries, or cakes.

Milling as Craft

As millers, our task is to transform grain into flour. Although the quality of our flour is hugely affected by the quality of our grain, the miller plays a significant role in the end result. Our goal as millers is twofold: to expose the grain fully, also known as damaging the starch (in this case, the term damaging just means to break up the starch granules within the grain berry), and to protect the nutrients. Whether working in a small regional stone mill or a large industrial mill, the miller aims to damage or expose the starch enough, but not too much. The perfectly damaged starch results in a flour with improved water absorption and the release of enzymes that feed yeasts. Flour with overly damaged starch can absorb water in excess, but will not be able to carry the weight of that water in baking, producing a flat loaf of bread.

As stone millers, we arrive at our flour by feel. We seek to release the oils and produce a uniform grind. We listen to the cadence of our grain entering the mill and to the sound of stone against grain—avoiding the sound of stone against stone. We feel the resulting flour with our hands, then fine-tune and make adjustments, as the mill’s settings affect particle size and starch damage, which in turn can affect the functionality of the flour. We keep an eye on the flour’s temperature, aiming to hold it well below 100°F, as we seek to protect the wheat germ—the wheat berry’s bank of nutrients, a highly concentrated package of unsaturated fats, B vitamins, folate, phosphorous, thiamin, zinc, magnesium, and vitamin E. Though our approach differs from industrial milling, where we really diverge from the milling industry is in our goal to not simply create a flour that functions well for the baker, but one whose nutrients are preserved in the milling process.

Our mill is a simple machine, belt-driven, with two stones that sit horizontal and parallel to one another. Our top stone is the runner stone, which rotates around the stationary bed stone. Grain enters the mill and becomes whole-grain flour—whole wheat or whole rye or whole spelt. This whole-grain flour has nothing removed. If it is to be sifted, it is then diverted to our bolter (or sifter), where it passes over various screens. Sifting is where the miller’s craft is honed, but before delving into the art of sifting, we must first understand the grain berry in its whole form.

As a whole, the wheat berry is a perfect combination of starch, protein, fiber, vitamins, and minerals. The majority of the wheat berry is the endosperm, about 82 percent by weight, mainly consisting of carbohydrates (in the form of starch), protein, and iron. The bran is the outer sheath, the grain’s shield against the elements as it grows in the field. It constitutes about 14 percent by weight and is rich in B vitamins, folic acid, fiber, and minerals. The innermost layer of the bran/outermost layer of the endosperm—or what lies between the bran and the endosperm—is the aleurone layer, a thin layer rich in minerals, fats, proteins, and enzymes. And the germ, which is the wheat berry’s embryo and the powerhouse source of nutrients, constitutes just 3 to 5 percent by weight.

When sifting flour, we are changing the ratio of these components—removing the lighter, larger granules. Sifting is achieved by gravity and velocity. We use a machine called a bolter, which consists of three chambers and strip brushes that rotate, sweeping the whole-grain flour over three sets of screens. Each screen has holes of a different size, and separate the flour by both weight and fineness to produce sifted flour, middlings, and bran. The middlings (also called farina and often found sold under the brand name Cream of Wheat) run past the first two screens because the granules are larger than the holes in the screens. The size of the holes in the screens and the pace of milling will determine the ratio of bran to starchy endosperm, the heaviest part of a whole-grain flour, in the end product. Sifting brings an exacting measure to our mill flow; the miller’s skill and attention ensure we produce a consistent product.

Flour by Type or Flour by Extraction

Since the majority of minerals are found in the bran (which contains ten to twenty times more minerals than the starchy endosperm), the amount of bran in flour is assessed by a measure known as ash. Ash is measured by incinerating a sample of flour at high heat. The organic components (starch, protein, sugar, and fats) fully combust, but the inorganic material (the minerals) are left behind in the form of ash. The ash is then weighed. Whole-grain, unsifted flour produces about 2 grams of ash per 100 grams of flour; pure endosperm contains 0.35 grams ash, so it follows that the lower the ash, the whiter the flour. In Europe, the measure of ash is how flour is designated and regulated. In Italy, for example, type 00—the fine white flour used in Neapolitan pizza—has a maximum allowable ash of 0.55 grams and is the equivalent of type 55 in France, which is a close equivalent of Germany’s type 550 (with a maximum allowable ash of .063 grams).

At Carolina Ground, we designate our sifted flour by extraction—the amount of flour left after sifting—instead of by ash. This is a less exact method, as mineral content can vary depending on soil and climate, but in this way, each year’s particular harvest lends its own signature to the flours we will produce. Whole-wheat or whole-grain flour is not sifted and is therefore 100 percent extraction—grain in, flour out. High-extraction flour is sifted flour from which the least amount has been removed. Our high-extraction flour is also called 85 Extraction, meaning 85 percent of the flour is left after sifting (15 percent has been sifted out). Our 75-Extraction flour has about 25 percent sifted out.

A good rule of thumb when navigating one’s way around the nomenclature, whether type (which refers to ash) or extraction, is that the higher the number, the more whole the product. High-extraction would be type 2 in Italy, type 110 in France, and type 1050 in Germany, and it is our 85 Extraction.

In the United States, there is an industry standard maximum allowable ash (although this is not regulated or overseen by the FDA), but this is not information readily available to us as consumers. Flour on the grocery store shelf is designated neither by ash nor extraction, but by intended use: all-purpose flour, or bread flour, or pastry flour, or cake flour. Without ash minimums or extractions, we as consumers are removed from the process. We are offered only white flour or wheat flour. When making a cake, measuring by volume works because the industry standard ensures that a cup measure of all-purpose flour or bread flour will weigh in fairly consistently at 125 grams, and a cup of cake flour at 120 grams. Our cold-stone-milled flour, produced within a less exacting framework, requires measure by weight to ensure success in recipes.

Converting Ash Value from European to US Standards

In determining ash content in the United States, flour is tested on a 14 percent moisture basis, whereas in Europe, flour is tested on a dry, or 0 percent moisture, basis. To convert the ash value, the math is simple—divide by 0.86: 0.52 percent ash at 14 percent moisture basis divided by 0.86 would be 0.60 percent ash at 0 percent moisture basis.

From Harvest to Mill

We grow winter grains in this part of the country, which in the South means seeds are planted in late fall and harvested in early summer. There are six different classes of wheat grown in the United States; these are divided by growing season (winter or spring), color (red or white), and hardness (soft or hard). Winter wheats are planted in the fall and harvested in the summer; spring wheats are planted in spring and harvested in late summer to early fall. Hard wheats are typically used for bread and pasta, whereas soft wheats are used for pastry, cakes, and biscuits. Typically, spring wheats are grown west of Kansas, in regions too cold for wheat to overwinter, and winter wheats, grown from Kansas east, require vernalization (exposure to cold) to initiate flowering. In the South, soft red winter wheat is the variety typically grown, and in North Carolina, we grow more soft red winter wheat than any other Southern state. However, the regional grains movement is redefining which wheat is grown where. Spring wheats are now being grown in western New York and Maine, and hard winter wheats are being grown in the South.

Here in the South, there is just a single grain crop per year (unlike our friends up north, who are able to grow both winter and spring wheats), and it must meet certain criteria to make it into our mill room. New crop grain undergoes lab tests and baking tests to ensure the resulting flour will have acceptable performance characteristics and is safe for human consumption.

The first thing I do when a sample of new crop grain arrives in our mill room is look at it. A visual inspection says a lot. A healthy crop has a visually detectable glow; plump, vibrant grain simply emanates strength. A healthy crop has a strong immune system, protecting it from insects and disease in the field. When I see this, I am reminded that we are working with plant life. Conversely, an unhealthy crop looks pallid; there are often broken kernels. Still, looks are not everything. A few years ago, I received a grain sample from one of my growers who warned me that the crop looked pretty bad. He said it had not rained in weeks and many of the wheat berries looked shriveled. When I received his sample, after a quick glance, I tossed a handful into my mouth. I chew on bread wheat to assess gluten strength. I’m looking for elasticity and extensibility—I want the grain to transform into the consistency of chewing gum. This crop, even with its share of shriveled berries, passed my chew test. I would come to learn that lack of rain at the right time (especially during those last ten days before harvest) contributes to increased protein. This crop would serve the baker well. For the grower, yields were low, but even after screening out the shriveled kernels at cleaning, we were able to offer him a better market for his grain than if it were sold for feed, and we landed on an especially flavorful crop with strong performance. Here is the value of a regional grains economy in action.

A visual inspection and chew test is followed by a measure of the test weight. Test weight is the actual weight of a bushel of grain. A true bushel weight should be 60 pounds for wheat and 56 pounds for rye and is typically a good measure of a quality crop. If test weight is low, this could be an indicator of disease or sprout damage, or just that it was a stressful growing year. If test weight is above 55 pounds and moisture is below 15 percent, the sample has made the cut and is sent off for lab testing.

Lab testing tells us, among other things, the grain’s protein value, though it is our baking tests that really guide our understanding of the grain before us. A protein number is one-dimensional, but the proteins that determine the baking characteristics of a grain are not. More important than the quantity of protein is the quality. Gluten accounts for 80 percent of the protein in wheat and delivers the strength and structure for bread wheat; the other 20 percent are soluble proteins that have no impact on bread-baking quality but do contribute to nutritional value. Gluten itself is made up of two proteins: glutenin and gliadin. Glutenin contributes elasticity and strength to dough and is derived from extrinsic factors such as planting date, seeding rate, soil fertility, weeds, and rain. We were able to transform crop of partially shriveled grain into viable bread flour in part due to those last ten days before harvest, which were especially hot and dry, just the right conditions for increased glutenin. Gliadin, on the other hand, provides extensibility or the ability to stretch the dough and contributes to dough’s volume. It is derived from intrinsic factors—the genetics of the seed variety. The gliadin is coded into the DNA of the variety of wheat—it is a set amount, while glutenin increases or decreases depending on growing conditions. The ratio of the gliadin to the glutenin is what defines the quality of the protein. Within an industrial system where bread is mass-produced and an average-size flour mill in the United States produces one million pounds of flour a day (according to the North American Millers’ Association), the ability to quantify the quality of protein becomes essential. Various lab tests are employed to measure mix time, water absorption, elasticity, and extensibility. At our small mill, producing between 1,500 and 2,500 pounds of flour a day, the baking test provides us with the information we need to know: Does the dough have sufficient strength to contain the gases produced by fermentation? Is it especially active? Is it thirsty? Can we make bread out of this crop?

Phenotypic Plasticity in Heritage Wheats

Glenn Roberts, owner of Anson Mills in Columbia, South Carolina, tells me one of his favorite terms is phenotypic plasticity. For the baker driven by the nuanced flavors of heritage grains, this is a term worth knowing. It refers to the adaptability of heritage wheats not only to extrinsic factors, but to intrinsic ones as well. While in modern wheats, the glutenin will vary depending on growing conditions, it is the change in the ratio of gliadin to glutenin that will have the biggest impact on the quality of the wheat for baking performance. Older varieties seem to have a tendency to adapt to their gliadin availability, so growing conditions that may have a more dramatic effect on modern varieties are more mitigated in heritage varieties.