How do I figure out the volume of a product instead of the weight? I have built my menu off weight, and I just learned it needs to be off volume. For example, I have 5 pounds of sour cream at $12.89 but I am only putting a tablespoon of sour cream on each taco. How do I figure this out?
– Shelby, Manager, Kaco, Fulton, Mo.
First, kudos on taking the time to cost your recipes to the tablespoon. Too many operators look at the big numbers like food cost percentage, but don’t realize the importance of knowing the costs of what is actually going on each plate.
You are right to question the difference between weights and measures in costing, and it’s most important to make sure you are using one or the other, but never mixing. And between the two, weight is better.
You may remember the grade school expression, “A pint’s a pound the world around.” What that means is that 1 pint by volume is equal to 1 pound by weight. The good news is that that rule of thumb is sort of true. The bad news is that it is really only true for water—and even then, not exactly.
Many operators make the mistake of confusing fluid ounces (volume) with ounces by weight. That’s easy to do because it is the same word! Ah, English.
To illustrate, just visualize three products, each 16 fluid ounces. In the first one you have a pint of blueberries. In the second, a pint of water. In the third a pint of molasses. If you put each one on the scale, you would see that the pint of water also weighs about 1 pound. But the blueberries would be much less, about 12 ounces. And the molasses is denser than water, so it would weigh more than 1 pound, close to 23 ounces.
As you note, in costing, it is important to make sure you are not mixing weight and volume. While one tablespoon of sour cream is one half of a fluid ounce, it may not weigh one-half ounce.
There are three ways to make sure your weights and volumes match for the purposes of costing:
- Weigh your standard portion of sour cream. If you find that one heaping tablespoon as you serve it weighs 0.5 ounces, you can do the math accordingly to find out that each plate includes about 8 cents of sour cream.
- Use a conversion table. Others have done the math for you by weighing standard volumes of various kitchen products. Since sour cream is slightly denser than water, for example, an 8-ounce cup of sour cream actually weighs 8.6 ounces. Since there are 16 tablespoons in a cup, you then know that one tablespoon weighs 0.54 ounces.
- Convert to volume. In some instances it may be easier to convert weight to volume than volume to weight.
No matter your method, keep the following in mind: You are right to be costing recipes; you need to be working in the same unit of measure, whether weight or volume; and be sure to update your costing with current pricing. Too many restaurants have detailed descriptions of their costs from years past without knowing the current costs of each menu item.
More on recipe costing here.