So… Let’s talk about ratios (%s) in bread making.

The basic math:
A % is nothing more than one number divided by another and then expressed as a %. This is done my multiplying the result of the division by 100.
A simple example – if we have one half of something – we write it as 1/2. If we complete this division, it will equal 0.5. Multiplied by 100 – it becomes 50 – or 50%. We should recognize that 1/2 or 0.5 or 50% all represent the same thing.

It’s all about weight:
While ratios or %s can be be used when measuring ingredients (1/3C or 1/2tsp for example), in bread baking – they refer to the ingredients primarily by weight.
It is important to understand that bread ingredients are not all equal weights by volume. For example – 1C of water weighs 236g (grams) while a cup of flour on average weighs 132g. We should also note that the weight of 1C of flour will vary significantly depending on how the flour is scooped and measured.

The statement – equal amounts of flour and water means very different things when measuring vs. weighing. This is a very common misunderstanding.

Where %s are used:
There are four common places in bread baking where %s (ratios) are used.

The Flour:
The Flour almost always represents the primary component of bread baking and each of the ingredients is expressed as a % of the flour weight. This is commonly referred to as baker’s percentage.
Since the flour always represents 100%, the sum of all the ingredients will almost always be 160% or greater. We will talk more about this.

The other % involving flour occurs when different flours are mixed together.
For example, we may make a bread with 1/4 or 25% whole wheat flour and 3/4 or 75% bread flour. In this case, the sum of all the flours (%s) should always equal 100%.

The remaining ingredients are all represented as a % of the flour (Remember – this is by weight).

Typically the second largest ingredient by weight – we measure the water weight compared to the flour weight and this ratio is commonly referred to as the hydration of the bread dough.
An example might be – we are using 1000g of flours and add 650g of water. The ratio of water to flour is 650/1000 or 0.65 or 65%. It is simply a ratio of the weights. The hydration is 65%.

Since we are talking about hydration, there is something to note. Different flours will absorb water differently and as such, the same hydration may feel very differently in different doughs depending on the flours that are being used. A 75% hydration dough may be very slack and sticky with a lower gluten flour, but relatively easy to manage with a high protein bread flour or a hard wheat whole grain flour. Hydration is a general indication of how wet a dough may be.

The other complication with hydration arises when adding other ingredients that contain some water content (eggs, honey, maple syrup, molasses, etc.). These will contribute to the overall wetness of the dough (what the hydration % is intended to represent) but are difficult to include in the calculation. Using a hydration % works best when a dough is comprised of simply flour water salt and yeast/starter.

Milk or buttermilk used instead of any (or all) of the water in a recipe will not really change the hydration. The hydration, in this case, is determined by adding the weights of each of the liquids together and then dividing by the total flour weight.

The most common range for water (liquids) as a % of flour is 55-85%. Lower %s will be very stiff doughs while higher %s will often be wet and sticky. There are some breads as high as 120% – but most recipes will fall between 55-85%. Bagels are an example of a low hydration dough.

The default % of salt for bread is 2%. The typical range for adding salt is 1.5 – 2.2%. It is good to note that the overall salt content of the bread is not 2% – but is actually lower when all of the ingredients are taken into account.

Yeast can be added from 0.1% to 2%. Most short rise recipes will be on the high end. No knead breads will use 0.1-0.2%. I find that around 0.8-1.2% gives nice performance. The main thing to note is that the higher the % – the faster the fermentation will be. To slow any bread down – simply reduce the amount of yeast.

For sourdough breads, we add the third ratio or %. A starter is really just another form of bread dough – it simply lacks salt. Just as above – the starter has a ratio of water weight to flour weight. It is also referred to as the starter hydration.
It is calculated the same way. Perhaps the most common starter hydration is 100%. This simply means that the water and flour weights are equal.

Often people add equal measures of flour and water (1C each for example). This will create a starter hydration of 236g (water weight) / 132g (flour weight) or 1.79 (179% hydration). This is a much different result than when weighing them.

The last ratio is the amount of starter added to a dough – again referenced against the flour weight. This ratio is typically 5-40%. Consistent with the yeast above, the more starter you add – the faster the fermentation will be. To slow a bread down, simply add less starter.

Varying the amount of starter has a secondary effect of influencing how sour a bread will be – as sourness is partly a function of fermentation time. Generally, less starter = longer fermentation = more sourness.

A poolish, a biga, a starter, a levain – the same rules apply – there is a hydration and in the cases where yeast is added, the % of yeast is typically very low.

For reference:
Sugars are most commonly added from 0-12%. Over 10% – you may need to increase the yeast/starter amount slightly.
Oils/Fats are most commonly added from 0-10%.

So – let’s recap the four places where %s are commonly used:
1. Mixture of different flours – we show the % of each of the flours being used – they must add up to 100%.
2. The baker’s % – the ratio of each of ingredients in the dough as a % of the total flour weight. The total of all %s will almost always be greater than 160%.
3. Dough/starter/preferment hydration – the ratio of all liquids by weight compared to the total of all flours by weight – this works best for doughs without extra ingredients and is most commonly the weight of the water divided by the weight of all the flours added together.
4. The % of starter – while technically just another ingredient in #2, it is often called out seperately.

An example to help clarify – here is a simple recipe:
250g whole wheat flour
750g bread flour
700g water
20g salt
200g 100% hydration starter

For the ratio of flours – the total flour weight is 1000g (250g + 750g). The whole wheat is 250g of the 1000g total or 250/1000 = 0.25 or 25%. The bread flour is 750/1000 = 0.75 or 75%. We might see this expressed as 25% whole wheat and 75% bread flour.

The water as a % is 700g divided by the total flour weight (1000g). 700/1000 = 0.70 or 70%. This is the baker’s percentage for the water.

Determining the hydration of the dough when using a starter or other preferment may be a little confusing. We need to remember that it is the ratio of the weight of all the liquids compared to the total weight of all the flours. In this case, the starter also contains flour and water and needs to be included when calculating the overall hydration.
We know the starter is 100% hydration (equal weights of flour and water) and weighs 200g. In this case, it is easy to recognize that the flour and water are each half of the 200g weight or that the starter is 100g each of flour and water.

The hydration is the the total water weight of 800g (700g + 100g from the starter) divided by the total flour weight of 1100g (250g + 750g + 100g from the starter). 800/1100 = 0.727 or 72.7% hydration.

The salt is 20g / 1000g = 0.02 or 2%. As noted earlier, the total weight of all of the ingredients in this recipe is 1920g (250g + 750g + 700g + 20g + 200g). The salt as a % of the overall dough is 20g / 1920g = 0.01 or 1%.

The starter is still measured as a % of the total flour weight of the recipe or 1000g in this case. The starter is 200 / 1000 = 0.20 or 20%. As a baker’s %, it is 20%.

The same recipe – now expressed by bakers %:
25% whole wheat flour
75% breed flour
70% water
2% salt
20% 100% hydration starter

From this information, we can recreate the same end result. The missing piece of information is simply the total weight of the flour. The good thing to note is that it can be any amount – for as long as we maintain the same ratios of all ingredients – we will get the same results. This is the major advantage of using %s. We can adjust the amount of dough up or down simply by varying the amount of flour.

In this case, if we wanted to make the loaves 10% larger the next time, we would simply increase the total flour weight by 10%.
How this would work and… why it’s valuable to think of the recipe in terms of %s rather than specific weights.

Our total flour weight was 1000g. 10% more is an additional 100g. 0.10 x 1000g = 100g. Our new total flour weight is 1100g.

To adapt the recipe, we now just recalculate each ingredient’s new weight.
We can do this two ways. We can multiply each one of them by 1.1 (110%) or we can just use the baker’s %s.

Our recipe expressed by bakers %:
25% whole wheat flour
75% breed flour
70% water
2% salt
20% 100% hydration starter

The first is the flour weights
The whole wheat flour is now 25% or 0.25 of 1100g. 0.25 * 1100g = 275g.
Our bread flour is now 75% or 0.75 of 1100g. 0.75 * 1100g = 825g.
We can quickly verify this is correct by adding them together (275g + 875g = 1100g).
The water is now 70% or 0.70 of 1100g. 0.70 * 1100g = 770g
The salt is 2% or 0.02 of 1100g. 0.02 * 1100g = 22g
Our starter is now 20% or 0.20 of 1100g. 0.20 * 1100g = 220g.

Our recipe, 10% larger is now:
275g whole wheat flour
825g bread flour
770g water
22g salt
220g 100% hydration starter

If we recalculate the hydration – the total water is now 770g + 110g (from the starter) or 880g. The total flour weight is now 275g + 825g + 110g (from the starter) or 1210g.
We divide 880g by 1210g. 880 / 1210 = 0.727 or 72.7%. As we can see, scaling the recipe up (or down) does not change the overall results – only the size of the dough.

If you wanted to make the recipe 33% smaller, you would subtract. Our total flour weight was 1000g, which was 100% of the flour. Simply subtract 33% from the 100% which is 67% or 0.67. Our new total flour weight is 670g (1000g * 0.67).

The first is the flour weights
The whole wheat flour is now 25% or 0.25 of 670g. 0.25 * 670g = 167.5g.
Our bread flour is now 75% or 0.75 of 670g. 0.75 * 670g = 502.5g.
We can quickly verify this is correct by adding them together (167.5g + 502.5g = 670g).
The water is now 70% or 0.70 of 670g. 0.70 * 670g = 469g
The salt is 2% or 0.02 of 670g. 0.02 * 670g = 13.4g
Our starter is now 20% or 0.20 of 670g. 0.20 * 670g = 134g.

Our recipe, 33% smaller is now:
167.5g whole wheat flour
502.5g bread flour
469g water
13.4g salt
134g 100% hydration starter

As before, the hydration will remain the same.

If we want to change our starter % from 20% to 15% because we want a slightly longer fermentation time, we simply recalculate the amount. In our original recipe with 1000g of flour, we would multiply by 0.15 (15%) rather than 0.20 (20%). Our new starter weight is 1000g * 0.15 = 150g.

Our recipe is now:
250g whole wheat flour
750g bread flour
700g water
20g salt
150g 100% hydration starter

Since we changed the amount of starter we added, we did change the dough hydration. The hydration is now the the total water weight of 775g (700g + 75g from the starter) divided by the total flour weight of 1075g (250g + 750g + 75g from the starter). 775 / 1075 = 0.721 or 72.1% hydration. This is slightly lower than our original recipe of 72.7%.

If we want our dough to be the same hydration as before (72.7%, we will need to add a little more water.

So – when we see someone share information on a bake that says:
30% whole wheat, 78% hydration, 25% 80% hydration starter

We can make some assumptions to fill in the missing pieces. We might assume that the other 70% of the flour is a white flour (typically the default). We don’t know if it was AP or bread flour. We don’t know how much salt was added, but could assume 2%. We also don’t know if the starter was recently fed or not. Some will indicate a 12hr old starter or something to that effect. In this example, we know that the weight of the starter was 25% of the total flour weight. We would expect this dough to be a bit faster due to a fairly high % of starter. It will tend to be less sour. We also know the water weight compared to the flour weight is 78%. Though a limited amount of information was provided – we could approximate the full recipe.

It is a good time to note that in bread baking, the recipe or list of ingredients is a small piece of the overall process. The flours used, how the dough was mixed, the fermentation temperatures, baking temperatures and method, etc will all dramatically alter the outcome even when the same ingredients are used.

Happy Baking to all.