The Difference Between Bleached and Unbleached Flour

3.6 based on 27 ratings

Updated on Oct 25, 2013

Grade Level: 4th - 6th; Type: Food Science/ Chemistry


Investigate whether there is a difference in rise between bleached and unbleached flour. This experiment also serves as a fun cooking lesson for kids and afterwards, you can actually bake the dough into yummy bread.

Research Questions:

Flour is a powder made from grinding cereal grains, other seeds, or roots. It is very universal and can be made into many different edible foods such as cookies, bread, crackers, pizza, pasta, and more. Some flour is bleached for commercial reasons and some isn't. Are there any differences between them in how fast the dough rises? In how puffy the dough gets? The texture?


  • Unbleached All-Purpose Flour
  • Bleached All-Purpose Flour
  • Sugar
  • Salt
  • Yeast
  • Two large mixing bowls
  • Measuring spoon and cups
  • Water
  • Saran/plastic wrap
  • Timer
  • Pen/paper for notes

Experimental Procedure

  1. Activate the yeast one tablespoon of yeast by putting it in with the two tablespoons of sugar.
  2. Wait 15 minutes.
  3. Add two cups of unbleached flour in one mixing bowl and two cups of bleached flour in the other.
  4. Dig a “pit” into the center of the flour.
  5. Add ½ tablespoon salt to each bowl.
  6. Add ½ of the yeast + sugar combination in each bowl.
  7. Add 3/4 cup of lukewarm water into each bowl.
  8. Knead the dough until it is well combined- not sticky but not dry. If it is too sticky, then add some flour, if it is too dry, then add some water (a little at a time!)
  9. When you are done, cover both bowls with plastic wrapa and leave both kinds of flour to rise.
  10. Watch which dough rises first and which one rose higher.

Terms/Concepts: Flour; Dough; Rise


Sofia PC is currently a college student with a deep interest in science who is aspiring to become a writer. She writes about all sorts of things across all subjects including, but not limited to; science, crafts, and fashion. She hopes to become a good writer so she can share her thoughts and experiences with the world and future generations.

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