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%

    Ready to run the numbers?

    Open Flour Protein Blend Calculator