Every baker has its own way of writing recipes

Some will simply use quantities (and for a beginner that’s the easiest to follow), some will also use percentages alongside. Using % comes handy whenever you want to scale up or down, make smaller or larger loaves. 

How do percentages work – the simple way

The amount of flour will always be the reference point. 

Say you use 500g flour for a standard loaf = 100%.

If you use 2 types of flour, say 400g bread flour and 100g wholemeal, this will be 80% bread flour & 20% wholemeal.

You then have the rest of the ingredients

350g water or 70% = 350g / 500g (total amount of flour)

100g starter, 20% = 100g / 500g (total amount of flour)

10g salt, 2% = 10g / 500g (total amount of flour)

Note that the % WON’T add up to 100%.

Should you want to make a smaller loaf instead, start with the amount of flour in mind and use % to figure out the amount of water, starter and salt required. 

For example: 400g flour will required 280g water (70% out of 400g), 80g starter (20%) and 8g salt (2%)

The amount of water in a recipe is also called dough hydration

The easy way to calculate dough hydration is by dividing the amount of water in the recipe to the amount of flour, as described above. 

There is however a more accurate way of doing it, which you may encounter in some recipes.

	When to use it?	Calculation	Hydration %
Simple way	Always a 100% hydration starter or leaven	350g water (in recipe) / 500g flour (in recipe)	70%
Accurate way	Different starter feedings/ leaven preparation	350g water (in recipe) +50g water (in starter) / 500g flour (in recipe) + 50g flour (in starter)	72.7%

Now, which one should you use? 

Since I always feed my starter with equal parts of water and flour (also called 100% hydration), I prefer keeping it simple. You may want to do the same.

However, if for example, you were to use a stiffer starter instead (fed with more flour than water), then the more advanced calculation is more suitable.

This is more precise if you want to keep the dough at the same hydration as if you were to use a 100% hydration starter. With a stiffer starter, you will have to increase the amount of water in the dough, should you want the results to be the same