Class 102 in the Fresh-Milled Flour Foundation Series
Store-bought flour isn’t made by simply grinding wheat berries. Instead, it goes through a series of steps that separate and refine the grain.
Flour is made from wheat by cleaning, conditioning, milling, and separating the grain, then refining the endosperm into a fine, uniform powder.
This process is very different from fresh milled flour, where the entire grain is ground and used immediately without being separated or refined (see → What Is Fresh-Milled Flour?).
Here’s what that process looks like step by step:
How Is Flour Made From Wheat?
Step 1: Cleaning the Wheat
Before milling begins, wheat berries are cleaned to remove:
- dirt
- stones
- plant debris
This ensures only clean grain enters the process.
Step 2: Conditioning the Grain
The wheat is then conditioned by adding a small amount of moisture.
This step softens the bran and makes it easier to separate from the rest of the grain.
Step 3: Roller Milling
The grain passes through a series of steel rollers.
These rollers gradually break the wheat kernel apart into its three components:
- bran
- germ
- endosperm
At this point, the grain is separated, and each part is handled individually.
History Note: The Shift to Modern Flour Processing
In the early 1900s, roller milling became the dominant method for producing flour. This process allowed mills to separate the wheat kernel into its individual parts – bran, germ, and endosperm – much more efficiently than traditional stone milling.
This made it possible to produce a finer, more consistent, and more shelf-stable white flour. However, it also meant that many of the nutrients found in the bran and germ were removed during processing (see → Fresh-Milled Flour Benefits: Nutrients in Whole Wheat Explained).
Step 4: Separating Bran, Germ, and Endosperm
Once the kernel is broken apart:
- the bran is removed
- the germ is removed
- the endosperm is kept for refining
This separation is what allows for the production of white flour.
Step 5: Milling the Endosperm
The endosperm is milled into fine flour and sifted for consistency.
This produces the soft, uniform texture most people recognize as store-bought flour.
At this point, the flour can be finished in different ways depending on the type of flour being produced.
How White Flour Is Made
White flour is made by removing the bran and germ and using only the endosperm.
This results in a flour that is:
- lighter in texture
- more shelf-stable
- more consistent in baking
Why Flour Is Enriched
As refined white flour became more common, nutrient deficiencies began to appear – especially in populations that relied heavily on processed grains. Conditions like anemia (iron deficiency), beriberi (vitamin B1 deficiency), and pellagra (vitamin B3 deficiency) became more widespread.
In response, enrichment standards were introduced in the 1940s in the United States. Certain nutrients – primarily iron and B vitamins (B1, B2, and B3) – were added back to refined flour to help address these deficiencies.
Later, in 1998, folic acid (a synthetic form of folate) was also added after research linked low folate levels to neural tube defects like spina bifida.
These nutrients are added back from external sources in isolated form, rather than remaining as part of the whole grain – meaning some, but not all, of the original nutrients are restored.
Step 6: Stabilizing the Germ for Shelf Life (for Whole Wheat Flour)
The germ contains natural oils, which make it nutritionally rich but also unstable.
Once exposed to air, these oils can begin to break down and go rancid (see → Does Flour Lose Nutrients Over Time).
To prevent this, the germ is stabilized.
This usually involves heat, which:
- deactivates enzymes that would break down fats
- slows spoilage
- extends shelf life
This allows flour to be stored for longer periods without spoiling, but it comes at the cost of reducing some of the germ’s nutrients.
Step 7: Recombining (for Whole Wheat Flour)
For whole wheat flour, the bran, germ, and endosperm are recombined before packaging.
So by definition, it contains all parts of the grain.
However, those parts have been:
- separated
- processed
- stabilized
- stored
before reaching your kitchen (see → Fresh-Milled vs Store-Bought Flour).
Why This Process Matters
How flour is produced affects both how it behaves in baking and what it provides nutritionally (see → Fresh-Milled Flour Benefits: Nutrients in Whole Wheat Explained).
Separating and refining the grain changes the texture and performance of flour—but it also removes a significant portion of the nutrients originally found in the grain.
Enrichment replaces a small number of those nutrients, but the overall structure and nutrient profile of the grain is still changed.
Next, we’ll look at what fresh milled flour is – and how it compares to this process when the entire grain is ground and used at home instead of being separated and refined.