While you think sourdough is complicated, it is not rocket science. Learn what the baker's percentage is and how to calculate recipe ingredients. With the baker's math and a bit of practice, you will soon be creating your own recipes with ease.
And if this topic still sounds confusing, use my sourodugh calculator to make the process simple and accurate.
What is the baker's percentage?
Baker's percentages, or baker's math, is how bakers express the amount of each ingredient in a bread recipe compared to the weight of flour, which is always set at 100%.
So, if a recipe says 70% water, that means 70 grams of water for every 100 grams of flour. This method helps keep your results consistent and makes scaling sourdough bread recipes up or down super straightforward.
The basics of baker's math
In baker's math, flour is your baseline and always represents 100%. Every other ingredient is calculated in relation to the flour's weight.
Water controls the dough's consistency. The ratio of water to flour is called hydration, and it affects everything from bread dough mixing to the final texture of your bread.
Salt and active starter (or levain) are just as important. Salt adds flavor, and the starter gives your dough the power to rise. Like water, their amounts are also measured as a percentage of the flour.
Baker's percentage formula
Here's the basic formula:
Baker's percentage = (Ingredient weight ÷ Total flour weight) x 100
And if you know the percentage but need the weight:
Ingredient weight = (Flour weight x Baker's percentage) ÷ 100
You can also calculate the flour weight if you know the weight of another ingredient:
Flour weight = (Weight of ingredient x 100) ÷ Baker's percentage of the ingredient
A real-life sourdough example
Let's say you want to bake a beginner-friendly sourdough loaf:
- Flour: Start with 500 grams (100%).
- Water: Choose 68% hydration. That's 340 grams.
- Starter: Go with 20%, which equals 100 grams.
- Salt: 2%, so 10 grams.
| Ingredients | Baker's Percentage | Weight |
| Bread flour | 100% | 500g |
| Water | 68% | 340g |
| Starter | 20% | 100g |
| Salt | 2% | 10g |
If you are starting, try using 65-70% hydration to keep the dough easier to handle. Once you get more practice, you can increase it to 70-75%, and eventually try 80% or higher for a more open crumb.
The sourdough starter amount is also flexible. As a beginner, start with 20%. That means your starter should be 20% of the total flour weight in your recipe.
Over time, you will learn how to adjust this percentage to make sourdough more sour (or less sour, too). You can also tweak the starter amount to suit the warmer conditions of sourdough summer baking.
As for salt, stick to 2% of the flour weight. It brings the flavor without taking over.
How to adjust sourdough bread recipes
Example 1: Adjusting dough hydration
Let's say your recipe looks like this:
| Ingredients | Weight | Baker's Percentage |
| Bread flour | 450g | 100% |
| Whole wheat flour | 50g | ? |
| Water | 375g | ? |
| Active starter (levain) | 100g | ? |
| Salt | 10g | ? |
To figure out the dough hydration level (how much water it has compared to the flour), you can use this formula:
(Ingredient weight ÷ total flour weight) x 100 = Baker's percentage
In this case: (375 ÷ 500) x 100 = 75%
So, the dough has 75% hydration.
If 70% hydration feels too sticky to handle, lower it to 70%. Use the reverse formula to calculate how much water you will need:
(Flour weight x Baker's percentage of the ingredient) ÷ 100 = Ingredient weight
For 65% hydration: (500 x 70) ÷ 100 = 350g
Now it is easier to handle.
Example 2: Adjusting flour amount
Imagine you have only 455 grams of flour instead of the 500 grams the recipe calls for. Can you still make bread?
The answer is yes. Just treat the 455 grams of flour as 100% and calculate the amounts for the other ingredients using baker's percentages.
| Ingredients | Baker's Percentage | Weight |
| Bread flour | 100% | 455g |
| Water | 70% | ? |
| Active starter (levain) | 20% | ? |
| Salt | 2% | ? |
You can determine the weights of the other ingredients using the reverse baker's percentage formula:
Ingredient weight = (Flour weight x Baker's percentage) ÷ 100
- Water: (455 x 70) ÷ 100 = 319 grams
- Starter: (455 x 20) ÷ 100 = 91 grams
- Salt: (455 x 2) ÷ 100 = 9 grams
Once calculated, your updated recipe will look like this:
| Ingredients | Baker's percentage | Weight |
| Bread flour | 100% | 455g |
| Water | 70% | 319g |
| Active starter (levain) | 20% | 91g |
| Salt | 2% | 9g |
Example 3: Adjusting starter amount
Let's say you have 70 grams of active starter (levain) and want to make bread. How do you figure out the amounts for the other ingredients?
You know that 70 grams of starter is 20% of the flour weight in a classic sourdough bread recipe.
Here is what you have so far:
| Ingredients | Baker's Percentage | Weight |
| Bread flour | 100% | ? |
| Water | 70% | ? |
| Active starter (levain) | 20% | 70g |
| Salt | 2% | ? |
To find the flour weight, use the reverse baker's percentage formula:
Flour weight = (Weight of ingredient x 100) ÷ Baker's percentage of the ingredient
For flour: (70 x 100) ÷ 20 = 350g
Now that you know the flour weight, you can calculate the others:
- Water: (350 x 70) ÷ 100 = 245g
- Salt: (350 x 2) ÷ 100 = 7g
Your final recipe will look like this:
| Ingredients | Baker's Percentage | Weight |
| Bread flour | 100% | 350g |
| Water | 70% | 245g |
| Active starter (levain) | 20% | 70g |
| Salt | 2% | 7g |
Baker's math = baking freedom
Baker's math is like your sourdough superpower. It is the secret formula for a perfect sourdough loaf every time. Whenever you create a bread recipe, you will use baker's math formulas.
It applies to a single loaf of sourdough bread, whether you make multiple loaves for your family or sell sourdough bread from your micro bakery.
And here is one more tip: don't blindly trust any sourdough recipe. Always double-check baker's percentages for each ingredient. I have seen salt amounts way off, like 3.5%, which can seriously interfere with bulk fermentation. Mistakes happen.
Let's talk sourdough
Are you still unsure about baker's math? Many home bakers find it tricky, too. If you are stuck or have a question, leave a comment below.
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