The main difference between all-purpose flour and bread flour is the percentage of protein in the product. Converting all-purpose flour to bread flour simply requires the addition of vital wheat gluten.
- Check the percentage of protein in your flour
Usually all-purpose flour has a protein content of about 10.5 percent, the lowest among most types of flour. Bread flour, on the other hand, has a protein content of 12 to 12.7 percent. Check the ingredients list on your product or go to the website of the flour company to find out the percentage of protein in the all-purpose flour you have purchased. The protein forms gluten when mixed with water; gluten is what gives bread its chewy quality.
- Measure out the ingredients
When you're substituting all-purpose flour for bread flour you need 1/2 to 1 teaspoon of vital wheat gluten for every cup of flour. This is the general rule if your flour has a 10 percent protein content. If it is lower, you must add more vital wheat gluten to it. This gluten additive is available in health food stores and most supermarkets.
- Sift the ingredients together
Make sure to sift the flour with the vital wheat gluten so it is evenly spread throughout. Whisk the ingredients together, and use it to replace the bread flour in the recipe.