The Ultimate Guide to Recipe Calculation
The Culinary Institute of America
Often you will need to modify a recipe. Sometimes a recipe must be increased or decreased. You may be adapting a recipe from another source into a standardized format, or you may be adjusting a standardized recipe for a special event, such as a banquet or a reception. You may need to convert from volume measures to weight, or from metric measurements to the U.S. system. You will also need to be able to translate between purchase units and recipe measurements. In some circumstances, you may be called upon to increase or decrease the suggested portion size for a recipe. Or you may want to determine how much the food in a particular recipe costs.
Using a Recipe Conversion Factor (RCF) to Convert Recipe Yields
To adjust the yield of a recipe to make either more or less, you need to determine the recipe conversion factor. Once you know that factor, you first multiply all the ingredient amounts by it. Then you convert the new measurements into appropriate recipe units for your kitchen. This may require converting items listed originally as a count into a weight or a volume, or rounding measurements into reasonable quantities. In some cases you will have to make a judgment call about those ingredients that do not scale up or down exactly, such as spices, salt, and thickeners.
NOTE: The desired yield and the original yield must be expressed in the same way before you can use the formula. If your original recipe says that it makes five portions, for example, and does not list the amount of each portion, you may need to test the recipe to determine what size portion it actually makes. Similarly, if the original recipe lists the yield in fluid ounces and you want to make 3 quarts of the soup, you need to convert quarts into fluid ounces before you can determine the recipe conversion factor.
The new ingredient amounts usually need some additional fine-tuning. You may need to round the result or convert it to the most logical unit of measure. For some ingredients, a straightforward increase or decrease is all that is needed. For example, to increase a recipe for chicken breasts from five servings to fifty, you would simply multiply 5 chicken breasts by 10; no further adjustments are necessary. Other ingredients, such as thickeners, aromatics, seasonings, and leavenings, may not multiply as simply, however. If a soup to serve four requires 2 tablespoons of flour to make a roux, it is not necessarily true that you will need 20 tablespoons (or 1 1/4 cups) of flour to thicken the same soup when you prepare it for forty. The only way to be sure is to test the new recipe and adjust it until you are satisfied with the result—and then be sure to record the measure!
Other considerations when converting recipe yields include the equipment you have to work with, the production issues you face, and the skill level of your staff. Rewrite the steps to suit your establishment at this point. It is important to do this now, so you can uncover any further changes to the ingredients or methods that the new yield might force. For instance, a soup to serve four would be made in a small pot, but a soup for forty requires a larger cooking vessel. However, using a larger vessel might result in a higher rate of evaporation, so you may find that you need to cover the soup as it cooks or increase the liquid to offset the evaporation.