Using Formula Percent

If you examine the examples given for simple scaling, formula percent, and baker’s percent, you will notice that they all yield the same results.  Mathematically, this makes sense.  You are simply taking an amount and multiplying it.  It doesn’t matter what type of mathematical manipulation you do, 2 * 2 still equals 4.

Why not use the basic method all the time then?  If all you ever want to do is to multiply the recipe by a scale factor, then the basic method is the best.  You don’t really need to calculate formula percents or baker’s percents.  If, however, you want to manipulate the recipe in other ways (i.e. total batch size, limiting ingredient, etc.), it is much easier to use the formula percent or baker’s percent formulas.

• Basic Scaling

• General Scaling Information

• Baker's Percent

• Using Baker's Percent

• Formula Percent

• Precision and Errors

Recipe Multipliers

Recipe Nutrition Calculator

[ Home ] [ Up ]

Formula percent, like baker's percent, makes manipulating a formula easier.

The corn tortilla formula, using formula percent, is:  masa = 2 cups = 228g = 48.4%; water = 1 cup = 237g = 50.3%; and salt = 1 tsp = 6g = 1.3%.

If you want to use 10 kg of masa in the new formula, divide the ingredient amount by the ingredient percentage (10 kg/48.4% = 20.66 kg).  This result is the total new batch size.  To find the other ingredients, multiply their formula percents times the new batch size.  Water is 50.3% * 20.66 kg = 10.39 kg, and salt is 1.3% * 20.66 kg = .27 kg.  Note that the amounts are the same as calculated with the baker’s percent (except the salt .26 kg versus .27 kg; the difference is due to rounding in the calculations).

You would use the same procedure for determining a new batch size based on any limiting ingredient.  Using the salt example from the baker’s percent section (salt = 100g), the new batch size would be 100g/1.3% = 7692g (7.69 kg).  The other ingredients would be masa = 7.69 kg * 48.4% = 3.72 kg, and water = 7.69 kg * 50.3% = 3.88 kg.

If you notice, these amounts in this example are slightly different from the amounts calculated using baker’s percent.  The baker’s percent total batch size is (3.85 kg + 4.00 kg + .1 kg) = 7.95 kg.  The formula percent total batch size is (3.72 kg + 3.88 kg + .1 kg) = 7.7 kg.  The difference is a 3% error.  This error is induced by rounding during the calculations.  It is also influenced by using the smallest measurement in the formula (small rounding errors affect small numbers more than large numbers).  If we use more precision, the amounts become 100g/1.27% = 7874g and the error becomes 1%.

Figuring new ingredient amounts based on a desired batch size is also simple using formula percent.  Simply take the new batch size and multiply it by each ingredient percent to determine the new ingredient amount.  Again, suppose we want to make a 1 kg batch.  Masa would be 48.4% * 1 kg = .484 kg, water would be 50.3% * 1 kg = .503 kg, and salt would be 1.3% * 1 kg = .013 kg.  Total batch size is .484 kg + .503 kg + .13 kg = 1 kg.