When I first started baking bread 40 years ago, I riffed on a recipe that listed the exact amounts I’d need for each ingredient, like 4 cups of bread flour, etc.. Then when I started getting into artisan bread, recipes became formulas, showing the relative amounts of the ingredients expressed as percentages. For instance:
The first time I saw that, my immediate reaction was, “WTF?” And my heart raced with anxiety. Nowadays, when I’m either recalling a recipe/formula, or even developing a new one, the percentages are all I think about.
As was explained to me, the percentages in a formula represent the ingredient amounts relative to the flour, which is always at 100%. So if we take the formula above, if I have 1000g of flour, then the amount of water I’ll need is 76% of that or, 760g. Easy, right?
But what about that “Total” item?
To be honest, I really didn’t pay too much attention to that figure until I started thinking about actual dough production and yields. At the time, I was starting to make bread to fulfill orders for luncheons and such. For instance, to feed a 200-person luncheon, I’d have to make 8 loaves scaled out to 1200g apiece, which mean that I needed to produce 9.6kg of dough.
The way I’d calculate how much I’d need was kind of a crapshoot. I’d start out with 5 kilos flour, then I’d apply the bakers percentages to get a weight. If we use that formula above, this would get me close to 9kg. So I’d go to 5.5kg and recalculate… It was tedious to say the least.
Thinking that there had to be a better way, I started doing some research and discovered that the total percentage in a formula is probably the most important number. This is because it is a representation of the total dough. Here’s a simple way to visualize what that means:
If you take the total percentage from the formula above, as Jeffrey Hamelman puts it in his book, “Bread,” (paraphrasing) that no matter what weight of dough we’re producing, there are 178.55 units that make up the dough. 100 of those units are flour, 76 of those units are the water, etc.
Without getting too technical about it, with that number, we can easily calculate the ingredient amounts we need for any given amount of dough we want to produce. In “Bread,” Hamelman talks about the conversion factor and using it to finding the amount for each ingredient.
Conversion Factor = Target Dough Weight / Total Percentage
So if I want to create a dough that weighs 1200g, given the formula above, the conversion factor would be:
Conversion Factor = 1200 / 178.55 which would be about 6.72
Multiplying each item percentage as a whole number by the conversion factor would give me the needed weight. For example, my flour weight would be 6.72 X 100 or 672g.
I have a simpler approach which basically accomplishes the same thing, but it’s more direct as I calculate the flour directly. Instead of coming up with the conversion factor, I just divide my target dough weight by the percentage, but expressed as a regular number. In this case,
Flour Weight = 1200 / 1.7855 = 672
From there, I just multiply the formula percentage relative to the flour weight. So the water I need would be:
Water = 672 X 76% = 511
Both methods will get you to the same place, but I like to shortcut my calculations as much as possible.
Let’s calculate the amounts we’ll need:
Target Dough Weight 1200g
With this method in hand, I now completely focus on how much dough I will need for a given bake, be it a single loaf or several. As long as I have an accurate formula, I will always be able to get the exact amount of ingredients I’ll need.
But that said, I usually add about a 0.5%-1% fudge factor to my total dough weight because weight will always be lost during processing, so if I need 1200 grams to make 4 X 300 gram loaves, I’ll usually calculate my dough weight to 1210 grams. You’ll have loss due to evaporation or dough sticking to tools, etc. With this fudge factor, you can be guaranteed that you’ll get the exact dough weights you’ll need for each loaf.