Protein makes the crumb
The protein in wheat flour, mainly glutenin and gliadin, forms gluten when it is mixed with water. More protein means a stronger, more elastic dough that traps gas well: chewy bread, open crumb, tall loaves. Less protein gives tender cakes and crumbly pastry. Matching the protein content to the recipe is one of the simplest ways to improve your baking.
Typical protein contents
| Flour | Protein |
|---|---|
| Cake flour | 7 to 9% |
| Pastry flour | 8 to 10% |
| All-purpose flour | 10 to 12% |
| Bread flour | 12 to 14% |
| High-gluten flour | 14 to 15% |
| Vital wheat gluten | about 75% |
Brands differ: two all-purpose flours can be a full point apart. Check the nutrition label: protein per serving ÷ serving weight × 100.
The Pearson square
To blend a stronger flour (protein P₁) with a weaker one (P₂) to reach a target T:
Share of the stronger flour = (T − P₂) ÷ (P₁ − P₂)
The target must lie between the two flours. To use vital wheat gluten instead, replace part of the weaker flour:
Gluten = total weight × (T − P₂) ÷ (75 − P₂)
Example
To make 1,000 g of flour at 11% protein from bread flour at 12.7% and cake flour at 8%:
- Bread flour: (11 − 8) ÷ (12.7 − 8) = 64%, so 638 g
- Cake flour: 362 g
- Or: about 45 g of vital wheat gluten mixed into 955 g of cake flour
What to aim for
- Cakes, biscuits, pie crust: 8 to 9%, or mix all-purpose flour with cornstarch, about 2 tablespoons per cup.
- Cookies and quick breads: 10 to 11%.
- Pizza: 11 to 13%, higher for long, cold fermentation.
- Sandwich bread and rolls: 11.5 to 12.5%.
- Bagels and hearth breads: 12.5 to 14%.
Tips
- Higher-protein flours absorb more water: add about 1 to 2% more water for each extra point of protein.
- Whole wheat flour has a similar protein content to bread flour, but the bran cuts the gluten strands, so it rises less.
- Protein quantity is not everything: gluten quality and the milling also matter, which is why bakers in some countries also look at the flour’s strength rating.