# Using Baker’s Math

Bread recipes written in baker’s math format can be intimidating. How do you know how much of each ingredient to measure out?

I think recipes written in baker’s math format are easier to use once you know how much dough you want to produce, which is almost always the case in a commercial bakery. If they know they want to make 50 loaves of bread each of which uses 20 ounces of dough, they know they’ll have to make at least 1000 ounces of dough, nearly 63 pounds of dough.

But I think a lot of home bakers tend to make the amount of dough the recipe calls, regardless of how much bread they really want, trusting the recipe developer to size the recipe appropriately. But there are times when you need a certain amount of bread: To make a dozen rolls, for example, or when you need to fit the dough into a certain size pan.

Here’s a simple way to rescale a recipe using baker’s math.

Suppose you have the following recipe in baker’s math format:

AP flour 70%

Semolina 30%

Water 65%

Sugar 2%

Salt 2%

Yeast 1%

Total 170% *(Note, this line is REALLY important!) *

Now, let’s decide how much dough to make.

Suppose I want to make a dozen rolls that will be 3 ounces each when scaled. So I want 36 ounces of dough.

Now, here’s the secret: **F ORGET THE PERCENTAGE SIGNS!** Just think of the ingredients as already being in ounces.

In other words, assume it makes 170 ounces of dough, a lot more than I need. I want 36 ounces of dough, so that’s 21.2% of 170. (36/170 = 0.212) Let’s call that the scaling factor.

So all I have to do is multiply each of the ingredients by the scaling factor of 0.212. Anything under 5 ounces I’ll show with 2 digits to the right of the decimal point.

AP flour: 70 x 0.212 or 14.8 ounces

Semolina: 30 x 0.212 or 6.4 ounces

Water: 65 x 0.212 or 13.8 ounces

Sugar: 2 x .212 or 0.42 ounces

Salt: 2 x .212 or 0.42 ounces

Yeast: 1 x .212 or 0.21 ounces

Total: 35.84 ounces

Well, it’s not exactly 36 ounces, the difference is due to rounding issues. In practice, if I want 36 ounces of dough, I usually aim for 37, I think it is better to have a little dough left over at the end or make the rolls just a little larger. *(In medieval England, there were severe punishments for bakers who short-weighted their customers, which is why the practice of providing 13 rolls originated and why it’s called a baker’s dozen.) *

But suppose you don’t want try to measure 0.21 ounces of yeast (just under 6 grams or not quite two teaspoons) because your scale isn’t that precise when measuring ounces and you don’t trust your measuring spoons, as I don’t trust mine.

OK, let’s do the whole thing again, this time in grams. This time, assume the original recipe makes 170 grams of dough.

I still want to make a dozen rolls around 3 ounces each. An ounce is 28.3495 grams, so 3 ounces would be 85.0485 grams, but let’s round that up to 90 grams to simplify the math somewhat. (That’s almost 6% more dough, by the way. If you’re counting carbs, that’s about 3 carbs more per roll.)

I need 90 x 12 or 1080 grams of dough.

^{1080}⁄_{170} = 6.35, so we multiply everything by the scaling factor of 6.35 to get the weight in grams. Anything under 20 grams I will show with one digit to the right of the decimal point.

AP flour: 70 x 6.35 or 445 grams

Semolina: 30 x 6.35 or 191 grams

Water: 65 x 6.35 or 413 grams

Sugar: 2 x 6.35 or 12.7 grams

Salt: 2 x 6.35 or 12.7 grams

Yeast: 1 x 6.35 or 6.4 grams

Total: 1080.8 grams.

This time it produced just a little more dough than my target amount.

*A brief side note on measuring spoons:*

*I have 3 sets of measuring spoons and they all result in different amounts of whatever it is I’m measuring.*

*As I have noted in the past, I tend to weigh all my ingredients, even water, and if something is under about 20 grams I use a small scale that measures in ^{1}⁄_{10} of a gram increments, they sell for under $20. *

When I bought a 5x5x13 inch Pullman pan I had to play around with how much dough to use for it so that as it rose it filled the pan to the top to get nice straight edges, but not to the point where the dough rose so much it blew the lid off. (King Arthur’s annual April 1st ‘oops’ blog had a picture of just such an explosion a couple of years ago; it was messy, I definitely want to avoid doing that.)

However, not all bread recipes rise the same amount. Most recipes I make in the Pullman pan take me at least two tries to figure out the right amount of dough to make. My rule of thumb for starting is to use 25 ounces of flour, that’s never produced enough dough to blow off the lid but with some recipes it doesn’t quite produce a nice flat top surface. The final quantity is usually somewhere between 25 and 29 ounces of flour. So we’ll use 25 here.

An advantage of starting with the flour weight is that all bread recipes have flour, they don’t all have sugar or other ingredients. Some, like Tuscan bread, don’t even have salt! So when I try a new recipe in the Pullman pan, I have the same starting point.

So, how do I adjust the recipe for this pan so that it uses 25 ounces of flour?

Well, remember that flour always represents 100% in baker’s math formulas, so it takes one extra step to come up with the scaling factor.

The flour is 100%, the total dough weight is 170%.

So, to have a dough made with 25 ounces of flour I need 170% of 25 ounces (25 x 1.70) of dough or 42.5 ounces. Now I’m back to where I was in the earlier examples, I know the amount of dough to make, and I can compute my scaling factor.

42.5/170 = 0.25.

AP flour: 70 x 0.25 or 17.5 ounces

Semolina: 30 x 0.25 or 7.5 ounces

Water: 65 x 0.25 or 16.25 ounces

Sugar: 2 x 0.25 or 0.5 ounces

Salt: 2 x 0.25 of 0.5 ounces

Yeast: 1 x 0.25 or 0.25 ounces

Total: 42.5 ounces. This time there was no rounding error!

When you start by choosing the amount of dough you want to make, then compute the scaling factor, and multiply the the baker’s percentages in the recipe by that scaling factor, you can scale any recipe quickly.