Most of the time, when I bake bread, I don’t look at a recipe.

Sure, I read a lot of books about bread and gather ideas from them, but more often than not, when it’s time to make the bread, it’s just me, my scale and a few numbers in my head.

I think about the previous breads I made, what worked last time with the specific mix of flours I am about to use. On a small slip of paper, or – more and more often these days – in a file in BreadStorm, I write down the proportions of ingredients as I decide what to do with them in the bread I am making today. And then, I start weighing ingredients.

This is possible because all breads are related.

Start with any bread recipe and strip away all ingredients that aren’t strictly necessary and soon you’ll notice that you are left with just four basic ingredients: flour, water, salt, yeast (or leaven). Similarly, working from the other direction, you can start with those ingredients, varying their proportions and maybe adding one or two extra ingredients (fats, seeds, nuts, maybe some sweeteners…) and get to almost any type of bread.

But how does all this work?

Luckily, it’s not hard at all.

It all comes down to just a few basic variables and then a lot of testing to find out the values that give YOU the best results when using your ingredients. Understand those variables and you can be the chief scientist in your kitchen — and start experimenting.

The Formula

As I already mentioned, to make great bread, all you need is four ingredients (three actually, but we’ll get to that later): flour, water, leaven, and salt. Change the amount of salt too much and your bread is no longer edible, so most of the time we just play with the proportions between water and flour.

Let’s start with an example: the most basic bread recipe of them all. To make the math as easy as possible, I am using 1000 grams of flour.

  • 1000g bread flour
  • 700g water
  • 10g fresh yeast
  • 20g salt

There you go. The most basic of bread formulas, a formula that already leads to a decent loaf of bread. Replace the yeast with some sourdough starter, or a pre-ferment, and you have great bread.

But now, the “magic”: By replacing the weights by numbers known as bakers’ percentage this formula becomes not just one formula, but the root for all formulas.

Here’s the same formula from above, this time written using bakers’ percentages instead of weights:

  • 100% bread flour
  • 70% water
  • 1% fresh yeast
  • 2% salt

See the logic yet?

Let me explain it: when using the bakers’ percentage notation, every ingredient is presented as its proportion compared to the total amount of flour in the dough.

This is important so I’ll repeat: a bakers’ percentage is not your regular percentage. It’s a number that tells how much of any ingredient is present in the dough, in relation to the amount of flour.

Now, the math.

Here’s how I got from these percentages to the final formula: I first decided to use 1000g of flour. This means that 100% = 1000g. Had I used two different flours, they would together be 100% (for example 20% wholemeal flour and 80% bread flour).

Next, we can calculate the other ingredients:

  • 70% of 1000g is 700g (in math speak: 1000 * 0.7 = 700)
  • 2% of 1000g is 20g (1000 * 0.02 = 20)
  • 1% of 1000g is 10g (1000 * 0.01 = 10)

And that’s it!

We now have used the formula to create a basic bread recipe for a kilo of white flour. In the same way, if you wanted to use 500 grams of flour, you’d just use 350 grams of water (500 * 0.7), 10 grams of salt (500 * 0.02) and 5 grams yeast (500 * 0.01).

This is how the bakers’ percentage notation combines all these different recipes into one. But this gets even more exciting!

So, let’s look at one more term: the hydration level.

Hydration simply means the amount of water in a dough, and is presented in bakers’ percentage.

In our example, the hydration is 70%, which – depending on the flour you use – can be just right or a little on the wet side.

I feel I should write more about this, but this really is it: Hydration means the amount of water in a dough.

Now, using these two tools (bakers’ percentage and hydration level), we can describe the formula in just two numbers. Two numbers that you can store in your mind and use to bake bread without ever looking at another recipe again:

Formula for basic white loaf (simplified version):

70% hydration. 2% salt. 1% yeast.

And as you bake more, the 2% for salt and 1% yeast become second nature, and then you can just go with the one number: 70% hydration.

You will be saying things like: “Today, I made bread at 80% hydration. Using 20% wholemeal wheat.”

And when another baker says his 100% hydration Ciabatta was a success, you’ll know exactly what he means.

For me, learning this a few years back was eye-opening, and now whenever I come across a bread recipe without bakers’ percentages written down, the first thing I do is to calculate them so that I can understand the dough and relate it in my mind with all the different breads I have baked previously.

So, I say if you have been avoiding these concepts because of the math involved, give them a go. At first, it might feel like work, but very soon, you will start seeing the benefits.