In a baker’s formula the flour is 100 per cent, always, and every other ingredient is expressed as a percentage of that flour weight. The percentages therefore sum to well over a hundred, which looks wrong the first time and is the whole point of the system.
It works because it scales. A formula written this way makes any batch size one multiplication away, and it makes two recipes comparable at a glance regardless of how much dough each produces.
What does a typical formula look like?
Four numbers describe most bread.
| Ingredient | Baker’s percentage |
|---|---|
| Flour | 100% |
| Water | 65–75% |
| Salt | 1.8–2.2% |
| Yeast, fresh | 1–2% |
| Total | around 170–180% |
To turn that into a batch, pick the flour weight and multiply. A kilogram of flour at 70 per cent hydration takes 700 grams of water and 20 grams of salt, and the arithmetic never gets harder than that.
Working backwards from a finished dough weight takes one extra step: divide the target weight by the total percentage to find the flour, then apply the rest.
What does hydration actually change?
How slack the dough is, how open the crumb becomes, and how difficult it is to handle. The percentage is water weight over flour weight, and the range in ordinary baking is wider than people expect.
Around 60 per cent gives a stiff dough that holds its shape and produces a tight, even crumb — the territory of bagels and some enriched breads. Around 65 to 70 is standard bread dough, workable by hand and forgiving.
Past 75 the dough becomes noticeably slack, and the open irregular crumb people associate with artisan loaves starts to appear. Past 80 it is closer to a batter, needs handling techniques rather than kneading, and is where most people’s first attempt goes wrong.
Why weigh instead of measuring by volume?
Because a cup of flour is not a fixed amount. Depending on whether it was scooped, spooned or shaken, the same cup can hold twenty per cent more or less flour — which on a 70 per cent hydration formula is enough to move it to 58 or to 85.
Water is consistent by volume and flour is not, so a recipe mixing the two conventions is precise in one ingredient and vague in the other. That is the single biggest difference between a recipe that works every time and one that does not.
It is also why baker’s percentages assume weight throughout. The system does not work in volumes, because the ratios it expresses are ratios of mass.
How does a preferment fit in?
By counting its contents toward the totals rather than sitting outside them. A starter or a preferment is flour and water, and both have to be included in the overall flour and water figures for the percentages to mean anything.
So a formula using 20 per cent preferment at 100 per cent hydration is contributing ten per cent of the total flour and ten per cent of the total water. Ignoring that makes the stated hydration wrong by exactly that amount.
This is the most common arithmetic error in a formula written by hand, and it is why calculating rather than estimating matters more the more preferment a recipe uses.
What does salt do besides taste?
Slows fermentation and strengthens the gluten network. That is why the range is narrow — below about 1.5 per cent the dough ferments too quickly and tastes flat, and above about 2.5 it noticeably retards the rise.
The percentage is of flour weight, which means it scales with the batch rather than with the water. A formula quoting salt as a fixed spoon measure is one that will be wrong at any batch size except the one it was written for.
Yeast behaves similarly and is more sensitive to temperature than to quantity. Adjusting fermentation time rather than yeast quantity is usually the better lever.
Does the system work beyond bread?
For anything built on flour, yes. Cakes, pastry and enriched doughs all express fat, sugar and eggs against the flour weight the same way, which is how a professional formula stays scalable.
It stops being useful where flour is a minor ingredient or absent. A sauce or a custard has no natural reference ingredient, so the percentages would be measured against something arbitrary and lose their meaning.
Questions people ask
How do I convert a volume recipe? Weigh one batch as you normally make it, then express those weights as percentages. After that it scales.
Should I include the water in a soaker? Yes, exactly as with a preferment. Anything contributing flour or water belongs in the totals.
Why is my total over 100 per cent? Because flour is the reference rather than the whole. It is correct.
Does hydration include milk or eggs? Their water content contributes, which is why enriched doughs quote hydration differently or not at all.
Can I scale a formula down freely? Yes, until the salt or yeast becomes too small to weigh accurately. Below that a smaller scale is needed.
Does flour type change hydration? Considerably. Wholemeal and strong flours absorb more, so the same percentage feels drier.
Weigh it and let the ratios do the work. The baker’s percentage calculator scales a formula to any batch size, and the dough hydration calculator works out the water for a target hydration or the hydration of a dough you already have.