Beginner Guide
How to Read a Sourdough Recipe (Baker's Percentages Made Simple)
Grams, percentages, hydration, ratios — sourdough recipes look intimidating until you learn the code. Here's the translation.
Sourdough recipes use weights in grams and "baker's percentages" (everything as a percent of total flour) so recipes scale cleanly and bakers can compare them. Once you learn that the flour is always 100% and everything else is measured against it, recipes stop looking like math homework.
Why grams, not cups
A cup of flour can vary by 30+ grams depending on how it's scooped. That variation ruins sourdough, which is sensitive to ratios. Weighing with a scale is the single most important accuracy upgrade in baking.
Baker's percentages explained
In baker's math, total flour = 100%. Every other ingredient is expressed as a percentage of that flour weight.
| Ingredient | Typical % | For 500g flour |
|---|---|---|
| Flour | 100% | 500g |
| Water | 70% | 350g |
| Starter | 20% | 100g |
| Salt | 2% | 10g |
So "70% hydration" means the water is 70% of the flour weight. This lets you scale any recipe up or down and compare two recipes instantly.
Reading a typical recipe
A line like "500g bread flour (100%), 350g water (70%), 100g starter (20%), 10g salt (2%)" tells you:
- It's a single loaf (~960g dough).
- Hydration is moderate (70%) — beginner-friendly.
- Starter is a standard 20%.
- Salt is a standard 2%.
A note on hydration and starter
Your starter contains flour and water too. For precise baker's math, count the starter's flour and water in the totals. For everyday baking, the simple version above works fine.
Frequently asked questions
What does "100% hydration starter" mean?
Equal weights of flour and water in the starter (e.g., 50g flour + 50g water).
Why is salt always around 2%?
2% by flour weight is the sweet spot for flavor and fermentation control across almost all bread.
Do I need to do math every time?
No — once you know your loaf size, the grams stay the same. Percentages just help you scale or compare.
Baker's percentages make recipes portable. SourdoughAI does the math for you — scale any recipe and it recalculates every ingredient automatically.