Baker's Math

I know there are a lot of folks out there with math phobia. I see them when my earth science students mutter that they thought they signed up for a science class, not a math class. What they, and a lot of other people, don't realize, is that math makes the world go round. We are fortunate that the universe appears to be structured in a very deliberate and organized way. I would argue that it is quite possible that until we are able to mathematically describe physical phenomena we see in our universe, we do not truly understand it.

Now, what does all of this have to do with baking bread? Well, to be honest, not a whole lot. I'm not worried about mathematically modeling the chemistry of bread baking, but I do believe that a few math skills in baking can be darn useful.

I won't lie to you. It took me a while to really grasp its usefulness, and many of you may find yourselves in that category forever. There's nothing wrong with that. You don't need baker's math to make great bread. But it comes in really handy when you want to start fiddling. Or scaling recipes. It really comes in handy there.

The whole idea of baker's math is that the recipe is presented as a list of percentages. Here's a sample recipe for french bread:

Flour 100

Salt 1.9

Yeast 0.55

Water 65

Two things you may notice right away: 1) the flour is 100%, 2) the total of all ingredients does not total 100%. All baker's math formulas are based on the flour totaling 100%. The other ingredients are listed as a percent of the flour's weight. How much weight is totally up to you. In this case, if you start with 4 cups of flour (weighing approximately 5 oz per cup), the required water would be 13 ounces. I obtained that number by using this first formula here. I plugged in 65 for the ingredient % (from the recipe above) and 20 ounces for the flour weight (4x5 oz). Multiply those two numbers together and divide by the 100 gives you how much water you need to add.

So, now if you want to use a baker's math recipe, you have a formula that can allow you to easily figure out how much of each ingredient you need. All you need to do is decide how much flour you want to start with and do one calculation per ingredient.

I used to pooh-pooh the use of the scale in the kitchen because it seemed laborious and unnecessary, but when it comes to making bread, the scale really is a rock star. Simply place your bowl on the scale, tare it, and start adding ingredients until you hit the requisite amount. Tare between each ingredient and there's no thinking involved!

But really, most cookbooks give the baker's weight and conventional measurements, so the above formula is only sometimes useful. So why the hubbub about baker's math?

Because I like to fiddle.

Lately, I've been fiddling with french bread. None of the recipes I tried quite gave me the results I was looking for, but many of the recipes had features I liked. But it is very hard to compare different recipes when they are written in conventional measurements. However, in baker's math, you can easily compare the recipes. Here are four french bread recipes from three different cookbooks that I converted to baker's percentages. The first thing to note is that they are quite similar. In fact, I could now probably write a set of parameters for what constitutes a french bread dough. And while there are a lot of factors that can influence the final product besides proportions of ingredients, it's an important place to start.


After making 5-6 different batches of baguettes, I took the above information and came up with a formula of my own I wanted to try. I decided on my percentages, and then I used the above formula to determine the weight of each ingredient. (I'll share that recipe in the not too distant future.)

What if you want to scale a recipe that is in conventional measurements? Then you need a different arrangement of the above formula.

With this formula, you need the weight of each ingredient, so you'll have to use a scale to get started. Once you have the weight of each, you can simply plug in the ingredient weight and flour weight to get the percent of each. Remember, in every case, the flour weight is 100%.

Again, baker's math is not required for bread baking, but it can be very useful when you want to compare recipes or scale them for a different yield. It may not be that hard to scale the measurements to increase a yield from 2 to 3 loaves, but what if you have a recipe that always makes loaves just a little smaller than you are happy with? With baker's math, you can simply and easily scale them up just a bit while still keeping all of the proportions equal! Handy dandy!