Bleaching and Color

• Chlorine oxide removes flour's original yellow pigment.Jupiterimages/Photos.com/Getty Images
  
  Bleached flour is pure white because it contains chlorine oxide, an edible bleaching agent. Unbleached flour has more of an ivory, cream or off-white appearance that is similar to the wheat from which it was made. Unbleached flour naturally bleaches itself through oxidation, typically over a 12-week period. Over time, unbleached flour will become dull in color, while bleached flour will remain bright white, since the bleaching agent has permanently removed the original yellow pigment.
  
  

The Aging Process

• Dough made with aged flour will have more elasticity and structure.Jupiterimages/Photos.com/Getty Images
  
  Although flour softens naturally with age, unbleached flour takes longer to do so. Bleached flour is ready to use sooner because of the bleaching agents, which accelerate the aging process, reducing the time needed from 12 weeks to 48 hours. As a result, bleached flour is less expensive and more readily available and is used more often in commercial cooking.
  
  

Baking Results

• Bleached flour is used for lighter, softer products.Jupiterimages/Photos.com/Getty Images
  
  Bleached flour creates breads and baked goods with higher volume and better texture than unbleached flour. This is because it has a lower level of gluten and a finer grain. Gluten proteins enable flour to form stronger, more elastic dough. Unbleached flour has a higher level of gluten than bleached flour and therefore is preferred when making yeast breads and other dense baked goods. Bleached flour generally yields a slightly lighter, softer product, making it useful for such things as pie crusts, cookies and waffles.
  
  

Nutrition

• The refining process removes essential nutrients from flour.Media Bank/Photos.com/Getty Images
  
  The wheat kernel consists of the bran, the germ and the endosperm. The bran is rich in fiber, while the germ has many vitamins and some protein, as well as healthy unsaturated fats. The endosperm is mostly starchy carbohydrates, some proteins and a small amount of B vitamins. Flour's milling process removes a wide spectrum of essential nutrients. When grain is made into refined white flour, more of the flour's naturally occurring vitamins, minerals and gluten are eliminated.