There have been times where all I have on hand is AP flour that has a fairly low protein content. It’s completely fine to use AP flour, but higher protein content means much better dough structure which, in turn, means much more rise. So to alleviate that, I purchased vital wheat gluten to increase the protein content in my dough.
When I first started using it, I was just going off advice I’d see online, like 1 teaspoon per cup or something like that. But since I’ve geeked out on the science of bread making, I’ve come to realize that to get consistent results, you have to remove the guesswork out of constructing dough. Bread making is so much more exacting than cooking – you can’t just throw in a little bit of this and little bit of that and expect consistent results. To that end, I needed a fairly foolproof way of calculating how much flour I’d need vs how much vital wheat gluten I’d need.
Enter the Pearson Square.
After doing a search online to find out how to calculate the proportions of VWG to flour I’d need, I ran across several discussions on the Pearson Square method. Talk about a face-palm moment! I knew this calculation from taking Statistics in college – but it had been 40 years since I even thought of it!
So what is it? The Pearson Square method is a statistical calculation that is used to determine a target ration based on two known rations. For our purposes, we use the protein percentages in our flour and our vital wheat gluten to determine how much of each we’d need for our recipe. Then all we have to do is choose the target protein percentage we’d like to have in our dough, and we can easily work out the amounts of flour and VWG we’ll need.
Look at the diagram below:
The only rule we need to be aware of is that the Target % has to be a number between our Flour % and the VWG %, and we’ll be able to do the calculation or…
Flour % < Target % < VWG%
Let’s do the calculation steps:
- First, write down the Target % you’d like to achieve in your final flour (We’ll call that “A”)
- Subtract Flour % from Target % (B)
- Subtract Target % from VWG % (C)
- Add B to C (D)
- Flour percentage you’ll need for your final flour is C divided by D (E)
- VGW percentage you’ll need for your final flour is B divided by D (F)
- Choose the amount of flour you’d like to use in your recipe (G)
- The amount of flour you’ll need is E times G (H)
- The amount of vital wheat gluten you’ll need is F times G (I)
I know, it looks like a bunch of algebra, but believe me it’s easy. Let’s apply some real numbers to this, shall we?
Flour protein % = 9.6%
Vital wheat gluten protein % = 77%
Target protein % in final flour = 14%
Amount of flour you want to use: 1000g
Given those numbers, let’s do the calculation steps from above:
- A: 14
- B: 14 – 9.6 = 4.4
- C: 77 – 14 = 63
- D: 63 + 4.4 = 67.4
- E: 63/67.4 = .9347 (93.5%)
- F: 4.4/67.4 = .653 (6.5%)
- G: 1000
- H: 1000 * 93.5% = 935 grams
- I : 1000 * 6.5% = 65 grams
So any time you need to up the protein percentage in your dough, just use the calculation above. For your convenience though, I created a spreadsheet that does the calculation for you. You can download it here.