Working Out Dough Hydration Without Fooling Yourself
Hydration is the weight of the water divided by the weight of the flour, written as a percentage. Five hundred grams of flour at 75% wants 375 g of water. The same flour at 68% wants 340 g. That is the entire idea, and every argument you have read about hydration comes down to a disagreement about which flour and which water are being counted.
The Baker's Percentage calculator on this site starts from a formula you already trust and scales it to a batch size. This page does something different. It takes the weights you actually put in the bowl — flour, added water, starter, salt — and tells you what hydration you truly built, then solves for how much water to add or hold back to land on a figure you choose.
A Starter Is Flour and Water, So Split It Before You Divide
A sourdough starter is not an ingredient in the way salt is. It is itself a mixture of flour and water, and both halves belong in the calculation: its flour joins the total flour in the denominator, its water joins the total water in the numerator. The split runs like this. Divide the starter weight by one plus its hydration written as a decimal, and you have its flour. Subtract that from the starter weight and you have its water. A 100 g starter maintained at 100% hydration is 100 ÷ 2 = 50 g of flour plus 50 g of water.
Now watch the two hydration figures separate. Take 500 g of flour, 350 g of added water and 100 g of 100% starter. Formula hydration divides the added water by the added flour only: 350 ÷ 500 = 70.0%, which is the number most recipes print. But the bowl actually holds 550 g of flour and 400 g of water, so true total hydration is 400 ÷ 550 = 72.7%. On one loaf the gap is survivable; it starts to matter once the preferment gets large or wet.
Two recipes can print the same 70% and sit nine points apart in the bowl. The table below holds the added flour and added water fixed at 500 g and 350 g, and changes only the preferment.
| Preferment | Its Flour | Its Water | Formula Hydration | True Total Hydration |
|---|---|---|---|---|
| 100 g at 100% | 50 g | 50 g | 70.0% | 72.7% |
| 150 g at 100% | 75 g | 75 g | 70.0% | 73.9% |
| 150 g stiff levain at 55% | 96.8 g | 53.2 g | 70.0% | 67.6% |
| 150 g biga at 65% | 90.9 g | 59.1 g | 70.0% | 69.2% |
| 150 g liquid levain at 150% | 60 g | 90 g | 70.0% | 78.6% |
The direction of the error depends on the preferment. A stiff 55% levain carries proportionally more flour than water, so it drags true hydration below the printed figure — 67.6% against a stated 70%. A liquid 150% levain does the opposite and pushes the same recipe to 78.6%, which is the difference between a dough you can shape with wet hands and one that spreads off the bench. Neither recipe is wrong. They are simply not comparable until both are resolved into flour and water.
The calculator also reports inoculation, which is the starter weight divided by the added flour weight. It matters because it is the dial that sets fermentation speed without touching the dough's feel: 100 g of starter against 500 g of flour is 20%, a normal figure for a six-hour bulk. Drop to 10% and the same dough in the same kitchen needs closer to nine or ten hours. Push to 30% and it can be ready in three, which is often too fast to build any flavour.
What Each Hydration Band Handles Like
Hydration is not a quality score and higher is not better. It is a different dough with different handling needs and a different crumb. The bands below describe true total hydration, preferment included. Read the handling column first, because that is the part you meet on the bench.
| Band | Breads It Covers | On the Bench | What the Crumb Does |
|---|---|---|---|
| 50–57% | Bagels, pretzels, hand-rolled pasta | Firm and dry to the touch; hard work without a mixer | Close and chewy, small even holes |
| 58–65% | Sandwich loaves, rolls, brioche, most pizza | Smooth and slightly tacky; kneads cleanly by hand | Fine and soft, slices without crumbling |
| 66–72% | Everyday sourdough, baguettes, ciabatta | Sticks to dry fingers, releases from wet ones | Moderately open with a good rise |
| 73–80% | Country loaves, pain rustique, focaccia | Spreads if left standing; wants folds, not kneading | Open and irregular, glossy crumb walls |
| 81–90% | Wet ciabatta, some pan pizzas | Poured and dimpled rather than shaped | Large holes up to a thumbnail wide |
| 90%+ | Batter-style ciabatta, rye slurries | Needs strong flour and a tin to hold any height | Extreme holes, fragile walls, gummy if underbaked |
Move between bands in 2-point steps, not 5. A dough that handles well at 68% is often barely different at 70% and unpleasant at 76%, and the changeover arrives faster than the numbers suggest. To push a dough wetter than it wants to go, add the last of the water after the salt, in small amounts — it takes on 10–15 g at a time far more readily than one pour.
Flour Absorption: The Variable No Recipe 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. Protein is the biggest lever: the gluten-forming proteins in a bread flour typically 12–14% protein bind more water than the softer proteins in an all-purpose flour at 10–12%. Bran matters just as much. Whole wheat and rye carry fragments of bran and germ, and those particles are physically absorbent as well as sharp enough to slice through gluten strands, so a whole-grain dough behaves as if it were several points drier than the number printed next to it. Rye brings pentosans, long-chain sugars that hold water tenaciously and make the dough sticky even when it is not especially wet.
Absorption also takes time. Flour keeps taking on water for twenty to thirty minutes after mixing, which is the mechanical reason autolyse works: mix flour and water, leave them half an hour, and a dough that was slack at minute one is noticeably tighter at minute thirty without a single fold. Judge a dough the moment it comes together and you will add flour you did not need.
The practical habit that solves both problems is to hold back 5% of the water. Mix everything else, rest twenty minutes, then add the held-back water if the dough still wants it. The table below gives starting allowances for a blend, measured against what the same recipe would need with white flour alone. Treat them as starting points: your flour may want 2–3% more or less, and the only way to know is to bake it once and write the number down.
| Blend | Extra Water to Allow | What Else Changes |
|---|---|---|
| 10% whole wheat | +1 to +2% | Almost nothing; a useful first step |
| 20% whole wheat | +2 to +4% | Ferments slightly faster; watch the bulk |
| 50% whole wheat | +5 to +8% | Shorter bulk by 30–45 minutes; tighter shape |
| 100% whole wheat | +8 to +12% | Still handles stiffer than the number suggests |
| 20% whole rye | +3 to +5% | Sticky immediately; do not add flour to fix it |
| 40% whole rye | +6 to +9% | Little gluten to work with; shape by hand, gently |
| 100% whole rye | +10 to +15% | Bake in a tin; the crumb sets from starch, not gluten |
What Salt Does to the Numbers and to the Clock
Salt percentage is calculated against total flour, which means the flour hiding in your starter counts. Ten grams of salt against 500 g of flour is 2.0%; the same 10 g against 550 g of total flour — because a 100 g starter at 100% added 50 g of flour — is 1.82%. Both sit inside the working window of 1.8–2.2%, and that window is the tightest one in bread baking. Below about 1.5% the loaf tastes flat and ferments uncomfortably fast. If you remember one figure, remember 2%: 10 g of salt per 500 g of flour, and 11 g once a 100 g starter has joined the bowl.
Salt does two things that touch hydration. It competes with the flour proteins for water, so a salted dough feels firmer in the hand at the same hydration, and a recipe that adds salt late seems slacker than the percentages predict. It also slows yeast, which is why dropping salt to speed a dough up produces a loaf that proofs on time and tastes of nothing. Salt is left out of an autolyse for the same reason: during those twenty minutes you want water moving into the flour unimpeded.
Solving for a Target Hydration
The solver runs one subtraction. Multiply the target hydration by total flour to get the water the dough should hold, then take away the water already present — added water plus whatever came in with the starter. The remainder is the water to add, or the water to hold back if the answer comes out negative. With 550 g of total flour and 400 g of water already in the bowl, a target of 75% needs 0.75 × 550 = 412.5 g, so you add 12.5 g. A target of 68% needs 374 g, so you hold back 26 g.
Two habits make the adjustment stick. The added-water figure you end up with is rarely the same as flour × target, because the starter has already contributed water — 362.5 g rather than 412.5 g above. And when you drop hydration, take water out of the mix rather than adding flour to soak it up, because added flour changes every other percentage in the formula and you will spend the next hour chasing a moving target.
Frequently Asked Questions
Because one counts the flour and water inside your starter and the other does not. Formula hydration divides added water by added flour only, which is what most recipes quote. True total hydration adds the starter's flour to the denominator and its water to the numerator. A recipe with 500 g flour, 350 g water and 100 g of 100% starter reads 70% one way and 72.7% the other — and 72.7% is what your hands feel.
Divide the starter weight by one plus its hydration as a decimal to get its flour, then subtract that from the starter weight to get its water. A 150 g starter at 50% holds 150 ÷ 1.5 = 100 g of flour and 50 g of water; the same weight at 150% holds 150 ÷ 2.5 = 60 g of flour and 90 g of water. Add each part to the matching total before dividing.
Most bakers land between 68% and 78% true total hydration. Start at 70% with a bread flour at 12–13% protein, which holds a shape between folds without fighting you. Push past 75% only once your shaping is consistent, because extra water exposes weak shaping rather than fixing it. Whole wheat and rye need more: a 30% whole wheat loaf at 75% feels much like a white loaf at 70%.
No. Water gives the dough the extensibility that lets large gas cells form, but those cells need gluten strength to hold them and a full fermentation to fill them. An 85% dough made with weak all-purpose flour, under-fermented and shaped roughly, bakes flat and gummy with a tight crumb. A well-fermented, confidently shaped 72% dough made with bread flour beats it every time.
Usually nothing. Your starter may be wetter than the hydration you entered, especially if you feed it by eye. Your flour may absorb less than the flour the recipe was written on. Or you may be judging too early: flour keeps absorbing for twenty to thirty minutes, so a dough that spreads at minute two often tightens by minute thirty. Rest it covered before you add anything.
Milk and eggs do, because both are mostly water: milk is roughly 87% water and a whole egg about 75%, so an enriched dough reaches its target with less added water than the number suggests. Oil does not hydrate flour at all; it coats protein strands and shortens them. That is why a brioche at 60% liquid and 20% fat feels far softer than a lean dough at the same 60%.