Baker's Percentages and Dough Hydration: Scaling a Sourdough Formula
October 29, 2026
Bakers express every ingredient as a percentage of the flour weight, which is always 100%. This makes recipes easy to compare, scale, and adjust. Hydration is the water weight divided by the flour weight. A dough with 500 g of flour and 350 g of water has a hydration of 70%.
A simple formula: flour 500 g (100%), water 350 g (70%), salt 10 g (2%). Adding 100 g of levain (sourdough starter) at 20% introduces its own flour and water. If the starter is fed at equal weights of flour and water (100% hydration), 100 g contains 50 g of flour and 50 g of water.
Skip the math and get your answer instantly:
Open the Percentage Calculator →True Hydration With a Starter
Total flour = 500 + 50 = 550 g. Total water = 350 + 50 = 400 g. True hydration = 400 ÷ 550 = 72.7%. Salt as a percentage of the total flour = 10 ÷ 550 = 1.8%. The total dough weight is 500 + 350 + 10 + 100 = 960 g. Many bakers state the starter as a percentage of the flour in the recipe (20%) but compute hydration on totals, so check which convention a formula uses. Higher hydration gives a more open crumb and a stickier dough that is harder to handle; 65% to 70% is easier for beginners, and 75% or more is for experienced hands.
| Ingredient | Weight (g) | Baker's % (of 550 g total flour) |
|---|---|---|
| Flour (500 + 50 in levain) | 550 | 100% |
| Water (350 + 50 in levain) | 400 | 72.7% |
| Salt | 10 | 1.8% |
| Total dough (with levain) | 960 |
Scaling to a Desired Dough Weight
Each ingredient's weight = its percentage × total flour. To make 1,500 g of dough from the formula above, first find the factor: 1,500 ÷ 960 = 1.5625. Multiply each weight: flour 781 g, water 547 g, salt 15.6 g, starter 156 g. Scale every ingredient by the same factor and the percentages stay the same. For a specific number of loaves at 800 g of dough each, multiply 800 by the number of loaves and divide by 960 to get the factor, then allow 3% for loss during mixing and handling.
Typical Percentages
Lean bread: hydration 60% to 75%, salt 1.8% to 2.2%, instant yeast 0.3% to 1%. Enriched doughs: add 5% to 15% sugar, 5% to 20% butter, and milk or eggs. Pizza: hydration 60% to 70%, salt 2% to 3%. Ciabatta: 75% to 85%. Bagels: 52% to 58%. Whole-wheat flour absorbs more water, so increase the hydration by 5 to 10 points. Salt below 1.5% weakens the dough and flavor.
Adjusting Formulas
Change one variable at a time and write down the result. To raise hydration by 5 points on 500 g of flour, add 25 g of water. To change the flour mix, apply the percentages to the combined flour weight. Use a scale instead of cups, because a cup of flour can vary by 20% in weight.
Frequently Asked Questions
What is hydration in bread?
Water weight divided by flour weight, as a percentage.
Why is flour always 100%?
It's the reference for all other ingredients.
How do I count the starter in hydration?
Split it into its flour and water and add them to the totals.
How much salt is typical?
About 1.8% to 2.2% of the flour weight.
How do I scale a formula?
Multiply each ingredient by the ratio of desired to current dough weight.