How to Bleach Wheat Flour

Flour is often bleached to help keep it from turning yellow.

Bleaching wheat flour is an extensive process, which requires cleaning, grinding and purifying the grains before they can be bleached. Since unbleached flour can turn a pale yellow with time --- due to a carotene-based enzyme known as xanthophylls --- mills began to introduce the food bleaching agent benzoyl peroxide to help ensure that the flour stays white. Though is chemical is a non-toxic organic compound, when combined with the cleaning and refining process, it can significantly reduce the flour's nutritional content. Does this Spark an idea?

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Separator
Aspirator
Break Rollers
Middlings purifier
Benzoyl peroxide
Silo

Instructions

- 1
  
  Clean the wheat by putting it through a separator. This machine is composed of a series of metal screens, which sifts out large foreign materials, such as pebbles or twigs. Afterwards, pass the wheat through an aspirator, which acts as a vacuum cleaner and sucks up any particles that are lighter than the wheat grains. Wash the wheat in warm water ---approximately 70 degrees F --- to remove any remaining debris. Then, dry the grains in a centrifuge.
- 2
  
  "Warm condition" the wheat by soaking it in warm water (approximately 115 degrees) for 90 minutes. This process will help the layer of bran that coats each grain to shed during the grinding process.
- 3
  
  Grind the wheat using large metal rollers known as "break rollers." The rollers differ in size and speed, and the friction they create helps to separate the wheat's inner grain from the bran. Afterwards, the wheat is separated by the machine into three categories: the coarse flour (farina), large pieces of the endosperm (semolina) and bran.
- 4
  
  Purify the farina or coarse flour by passing it through a "middlings purifier." In this apparatus, air blows through screens to remove the lighter remnants of remaining bran before the grains pass through. Next, pass the purified grains through a smooth roller, which will crush them into flour.
- 5
  
  Mix benzoyl peroxide into the flour at approximately 40 mg. peroxide for every kilogram of flour (roughly 0.0014 oz. per every pound). Finally, store the wheat in a silo for approximately two months --- which will allow the flour to mature before it is packaged and shipped.