Understanding Baker's Percentage and Dough Hydration
Baker's percentage is the notation system that professional bakeries have used for well over a century, and it is the single most useful piece of technical vocabulary a home baker can learn. The rule is simple enough to state in one sentence: total flour weight is always 100%, and every other ingredient is expressed as a percentage of that flour. Water at 700g against 1,000g of flour is 70% hydration. Salt at 20g against the same flour is 2%. The percentages do not add up to 100 — they are ratios against a fixed reference, not slices of a pie, and this is the detail that confuses most people the first time they meet the system.
The payoff is that a formula written this way is scale-independent. A ciabatta at 100% flour, 80% water, 2% salt and 0.5% yeast behaves identically whether you are making one 800g loaf at home or three hundred of them in a deck oven, because the relationships between ingredients never change. You choose your flour weight, multiply through, and the dough you get has the same feel, the same fermentation speed and the same crumb structure every time. Volume-based recipes cannot do this, because scaling a cup measurement compounds the error in how that cup was filled.
Why Your Stated Hydration and Your Actual Dough Disagree
Here is the mistake that causes more confusion in sourdough baking than any other, and it is the reason the calculator above asks for your starter's hydration separately. A sourdough starter is not an ingredient in the way salt is — it is itself a mixture of flour and water. A 100g starter maintained at 100% hydration contains 50g of flour and 50g of water. Both of those belong in the calculation: the 50g of flour joins the denominator, and the 50g of water joins the numerator.
Ignore this and the numbers drift badly. Take a formula of 500g flour, 350g water and 100g of 100% starter. Divide 350 by 500 and you get 70% — that is the formula hydration, and it is what most recipes print. But the dough actually contains 550g of flour and 400g of water, which is 72.7% true total hydration. On a single loaf that gap is manageable. At a stiff 55% starter or a wet 150% liquid levain, or at a high inoculation rate of 30–40% for a fast summer bulk, the two figures separate by several percentage points and you end up wondering why a "70% dough" is slackening on the bench like an 80% one. The calculator shows both numbers side by side so you always know which one a recipe meant.
What Each Hydration Band Actually Feels Like
Hydration is not a quality score. Higher is not better; it is simply a different dough with different handling requirements and a different crumb. The table below maps the practical bands, and it is worth reading before you chase the very open crumb you have seen photographed, because doughs above 80% need strong flour and a confident hand more than they need a good recipe.
| Hydration | Typical Breads | Handling | Crumb Result |
|---|---|---|---|
| 50–57% | Bagels, pretzels, pasta | Stiff; needs a mixer or real effort | Tight, chewy, dense |
| 58–65% | Sandwich loaves, brioche, rolls | Smooth, easy to knead by hand | Fine, even, soft |
| 66–72% | Everyday sourdough, baguettes | Slightly tacky; the reliable range | Moderately open, good rise |
| 73–80% | Artisan country loaves, pain rustique | Wet hands, coil folds, no kneading | Open, irregular, glossy |
| 81–90% | Focaccia, ciabatta | Poured rather than shaped | Very open, large alveoli |
| 90%+ | Wet ciabatta, some rye slurries | Strong flour essential; batter-like | Extreme holes, fragile structure |
Flour Absorption: The Variable Nobody Prints
Two bakers can follow the same 75% formula with the same care and end up with visibly different doughs, because flour is an agricultural product and its thirst varies. Protein content is the biggest lever — the gluten-forming proteins in bread flour bind more water than the softer proteins in all-purpose — but bran content matters just as much, which is why whole wheat and rye behave as if they were several percentage points drier. Whole grain flours also absorb water slowly, continuing to take on moisture for twenty or thirty minutes after mixing, which is the entire reason autolyse exists as a technique.
Ambient humidity plays a smaller but real role. Flour stored in a damp kitchen through a monsoon season already carries moisture, and a formula calibrated in dry winter air will run wetter. None of this makes the percentages useless — it makes them a starting point you adjust by 2–3% and then record. Once you have written down that your particular flour wants 72% rather than the 75% a recipe printed, that number is yours permanently.
| Flour | Protein | Hydration Shift | Note |
|---|---|---|---|
| Cake / pastry flour | 7–9% | −5% | Too weak for open-crumb bread |
| All-purpose | 10–12% | −2 to −3% | Works to about 75% |
| Bread flour | 12–14% | baseline | What most formulas assume |
| Whole wheat | 13–15% | +5 to +8% | Bran drinks; rest before judging |
| Whole rye | 8–11% | +10 to +15% | Pentosans, not gluten; sticky |
| Italian tipo 00 | 11–13% | −3 to −5% | Fine grind, extensible, pizza-oriented |
The Other Percentages That Matter
Salt, 1.8–2.2%. This is the tightest window in bread baking and the one the calculator flags for you. Below about 1.5% the loaf tastes flat and ferments uncomfortably fast, because salt is a mild brake on yeast activity as well as a seasoning. Above 2.5% fermentation slows noticeably and the crumb tightens. Two percent of total flour is the number to memorise: 10g of salt per 500g of flour.
Inoculation, 10–30%. This is the preferment as a percentage of the main flour, and it is the primary dial for controlling fermentation speed. A 10% inoculation in a cool kitchen gives you a long, flavour-developing bulk of six hours or more. A 30% inoculation in a warm kitchen can finish in two and a half. Adjust inoculation for the temperature of your room rather than fighting the clock.
Fat and sugar, 0–20%. Both are enrichments, and both interfere with gluten development. Fat coats protein strands and shortens them, which is exactly what you want in brioche and exactly what you do not want in a lean country loaf. Sugar above roughly 10% starts drawing water away from the yeast osmotically, which is why heavily sweetened doughs ferment slowly and often call for more yeast or an osmotolerant strain.
How to Use the Calculator Above
Enter the flour, water, salt and preferment weights from the recipe you are working with, then tell the tool what hydration your starter is maintained at — 100% if you feed it equal weights of flour and water, 50% for a stiff levain, 150% for a liquid one. The panel resolves the preferment into its flour and water components, reports both formula and true hydration, checks your salt against the standard band, and gives you the total dough weight along with the weight of each piece if you are dividing the batch.
The solve for target hydration field works in reverse. Set the hydration you want, press recalculate, and the tool rewrites the added-water figure so that the finished dough — preferment water included — lands on that number. This is the fastest way to take a recipe written at 68% and push it to 75% without doing the algebra by hand, and it is also how you correct a formula after switching from all-purpose to whole wheat.
Frequently Asked Questions
Our artisan sourdough guide walks through a full 75% hydration bake with timings, folds and troubleshooting.