Question: What is the difference between all purpose flour and bread flour?
By: Jo Ann Simanton
Published: April 17, 2011

I have been baking bread for many, many years and have always used all purpose flour with great success.  Would I benefit by using bread flour?

Answers:
Chris Paulk

Bread flour has a higher percentage of protein which makes the gluten stronger when making bread. This will make the  bread hold together better when it bakes. All purpose flour is a mixture of hard (high protein) wheat and soft (low protein) flour.
Lorrie Perencevic

Specifically, "bread flour" comes from primarily high-gluten hard red wheat and often has a small amount of barley flour and Vitamin C (ascorbic acid) added. The barley flour acts as a catalyst for the yeast, causing the bread dough to rise more effectively. The Vitamin C aids in developing the gluten in the wheat, resulting in a finished bread product that rises a bit higher and maintains a springy, cohesive texture. "All-purpose flour" is typically a combination of both high and low gluten wheat, so does not produce quite as good results for yeast breads.
There is also a difference in protein levels, with all-purpose flour ranging between 11% and 12% protein, and bread flour usually ranging between 13% and 14%. The higher protein content also contributes to stronger gluten.
You can certainly use all-purpose flour for your bread-baking, but you may notice a difference in your finished baked goods. Of course, you can offset the difference by keeping barley flour on hand and replacing a small amount of your all-purpose flour with it in your bread recipes.
In spite of all this, bear in mind that no matter how much gluten and protein is in the flour, the gluten is developed through the kneading process. Insufficient kneading can and will result in yeast breads that do not rise well, have large holes, and/or have a coarse and crumbly texture. So even if you use the finest of bread flour, do not neglect to work that dough! Likewise, if you are using all-purpose flour but you knead the dough thoroughly and let it rise in a warm, moist environment, you can usually achieve excellent results.
However, it is NOT a good idea to use bread flour in place of all-purpose flour for certain items. Cakes and pastries for instance, tend to develop a "toughness" in their texture when baked with the higher-gluten bread flour, so all-purpose flour is definitely preferable for those finer baked goods.
Happy baking!