Flour Protein Blend Calculator Formula

Understand the math behind the flour protein blend calculator. Each variable explained with a worked example.

Use the Flour Protein Blend Calculator

Formulas Used

Flour A Weight

flour_a_weight = total_weight * (1 - (target_protein - flour_a_protein) / (flour_b_protein - flour_a_protein))

Flour B Weight

flour_b_weight = total_weight * ((target_protein - flour_a_protein) / (flour_b_protein - flour_a_protein))

Resulting Protein

result_protein = target_protein

Flour A Percentage

flour_a_pct = (1 - (target_protein - flour_a_protein) / (flour_b_protein - flour_a_protein)) * 100

Variables

VariableDescriptionDefault
target_proteinTarget Protein(%)12
flour_a_proteinFlour A Protein(%)10
flour_b_proteinFlour B Protein(%)14
total_weightTotal Flour Needed(grams)500
fraction_bDerived value= (target_protein - flour_a_protein) / (flour_b_protein - flour_a_protein)calculated

How It Works

How to Blend Flours for Target Protein

Formula (Weighted Average / Alligation)

Flour B fraction = (Target - Flour A protein) / (Flour B protein - Flour A protein)

Flour A fraction = 1 - Flour B fraction

This linear blending formula works because protein content mixes proportionally by weight. It assumes both flours have the same moisture content (approximately true for most commercial flours).

Common Flour Proteins

  • Cake flour: 7-9%
  • All-purpose flour: 10-11.5%
  • Bread flour: 12-13%
  • High-gluten flour: 14-14.5%
  • Vital wheat gluten: 75-80%

    • Worked Example

    Blend 10% AP flour and 14% bread flour to get 12% protein, 500 g total.

    target_protein = 12flour_a_protein = 10flour_b_protein = 14total_weight = 500
    1. 01Flour B fraction = (12 - 10) / (14 - 10) = 2/4 = 0.50
    2. 02Flour A = 500 x 0.50 = 250 g
    3. 03Flour B = 500 x 0.50 = 250 g
    4. 04Check: (250 x 10 + 250 x 14) / 500 = 12.0%

    Frequently Asked Questions

    Why does protein percentage matter in bread?

    Protein (specifically glutenin and gliadin) forms the gluten network that traps gas and gives bread its structure. Higher protein flours produce chewier bread with better rise. Lower protein flours make more tender cakes and pastries.

    Can I add vital wheat gluten instead of blending?

    Yes. Add about 1 tablespoon (9 g) of vital wheat gluten per cup (125 g) of all-purpose flour to approximate bread flour. This raises the protein by roughly 2 percentage points.

    Does protein content affect hydration?

    Higher protein flours absorb more water. When substituting a higher protein flour, you may need to add 2-5% more water to achieve the same dough consistency.

    Ready to run the numbers?

    Open Flour Protein Blend Calculator