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: FORGET 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.