The Most Misunderstood Word in the Kitchen

Why is weight and volume so confusing? It boils down to one word: “ounce.”

An ounce refers to weight, while a fluid ounce refers to volume. The abbreviations look similar—oz and fl oz—and both appear throughout a school kitchen. Scales display ounces. Measuring cups, scoops, spoodles and ladle labels are often shortened to ounces instead of fluid ounce. It is easy to assume they all measure the same thing. They do not.

Weight tells us how heavy food is. It is measured in ounces and pounds using a scale. Volume tells us how much space food takes up. It is measured in cups and fluid ounces using measuring cups or portioning utensils.

This matters because a 4 fl oz spoodle does not mean everything placed in it will weigh 4 oz. The utensil holds ½ cup, regardless of whether it contains shredded lettuce or blueberries. Each food has a different density, so the weight of that ½-cup portion will vary.

The confusion becomes especially important when a production record lists a serving as “2 oz,” for example. That abbreviation indicates weight, so the food should first be weighed on a scale. Once the 2 oz portion is established, staff can determine which scoop or spoodle the weighed portion fits in closest to level.

Measuring a serving the wrong way can result in too much or too little food being served. That affects food costs, nutrition information, meal-pattern requirements, special diets, inventory and reimbursement.

The solution starts with one quick question: Does the recipe or production record say oz or fl oz?

If it says oz, use a scale to measure, then find the utensil that fits. If it says fl oz or cups, use the correct volume-measuring utensil. To make serving or ingredient sizes more foolproof on product records and recipes, write WT-OZ or FL-OZ to help eliminate confusion.

Weight vs. volume is never a one-time training topic. The more detail production records and recipes provide, the less room there is for confusion. Listing the weight, equivalent volume and correct serving utensil, such as 2.5 oz weight/½ cup/4 fl oz spoodle, shows staff exactly how to portion the food and the weight to use for calculating leftovers. Continuous training and better instructions lead to improved accuracy and confident employees.