Flour Know-How
Protein content differs among types (and brands) of flour and is an important consideration in baking—the higher the protein, the stronger the gluten. Gluten translates into structural support, necessary to give croissants and other yeast-raised breads their loft and chew. But too much protein would lead to a tough croissant.
Most flours don’t list protein content on the package. Cake flour, made from soft wheat, has the lowest amount of protein, 6 to 8 percent, depending on brand. Bread flour has the highest, at 12 to 14 percent. All-purpose flour falls in the middle, with a protein content of 10 to 12 percent. That makes it ideal for this recipe, with just enough protein to encourage maximum volume in the croissants. Use the highest-quality flour you can.