Converting recipes is a very important technique. It is a skill you will probably use many times. There is no "best" yield to write recipes for, since every individual or occasion is different.
Nearly everyone can double a recipe, or cut it in half. It seems more complicated to change a recipe from 10 to 18 portions. Actually the principle is quite easy. You multiply each ingredient by a number called a Conversion Factor:
1. Divide the desired yield by the recipe yield:
| new yield | ||
| ————- | = conversion factor | |
| old yield |
2. Multiply each ingredient quantity by the conversion factor:
In order to do this in the U.S. system, you will usually have to convert all weights to ounces and all volumes to fluid ounces. This is not necessary in the metric system.
EXAMPLE: You have a recipe for 10 portions of Broccoli Mornay, requiring 3 lbs of broccoli and 2-1/2 cups Mornay Sauce. Conver to 15 portions:
| new yield | 15 | |||
| ————- | = | —- | = | 1.5 |
| old yield | 10 |
Broccoli: 3 lbs. X 1.5 = 48 ounce X 1.5 = 72 ounce = 4 lbs. 8 oz.
Sauce: 2-1/2 cups X 1.5 = 20 ounce X 1.5 = 30 ounce = 3-3/4 cups