A Pint’s Not A Pound
I’d like to go back in time and punch the guy who thought it’d be a good idea to force two different systems of measurement to share the same name.
Exhibit A: the ounce, a measurement of weight. You know, how heavy something is. Exhibit B: the fluid ounce, a way of measuring volume; aka how much space something takes up
The confusion begins with water. Water weighs one ounce per fluid ounce, leading many people to assume that the two terms are interchangeable, different ways of saying the same thing. Those people would be wrong (see Exhibits A & B).
It’s no coincidence water has a volume equal to its weight. The fluid ounce came about for the express purpose of measuring how much space one ounce of water would occupy. It didn’t matter if a jug was tall and skinny or short and squat; so long as it held ten pounds of water, it was sold and taxed as a gallon (Imperial).
Originally, fluid ounces only applied to beer, wine and other water-like substances the government wanted to regulate. But in the late 1800s, American cookbook author Fanny Farmer popularized using an eight fluid ounce “cup” as the basic unit of measurement for all ingredients. This was a huge improvement over the previous system, where recipes called for subjective measurements like “a saucer of flour” and “a lump of butter.”
Things got confusing somewhere between then and now when companies like Pyrex and Anchor began mislabeling their cup measures. Grab yours and take a look. You’ll find little red markings to indicate liters, milliliters, cups and ounces, despite the fact that measuring cups are physically incapable of measuring ounces. If you ever buy a compass from Pyrex, expect it to be labeled North, South, East and Hot.
I don’t have a problem with using cups to measure an ingredient if that’s what a recipe calls for. I have a major problem when manufacturers systematically imply ounces are something you can measure in a cup.
Some people may roll their eyes and chalk it up to semantics, but by equating ounces to fluid ounces, these companies lead people to believe that when a recipe calls for 8 ounces of honey, filling their cup to the 8 ounce mark will give them 8 ounces of honey. Unfortunately, thanks to a little thing called density, they wind up with 12 ounces instead.
The difference between 8 ounces of honey and 8 fluid ounces of honey isn’t semantics, it’s a quarter of a pound.
With measurements that far off base, you don’t follow recipes, you fail them.
If you see a recipe that calls for cups, by all means grab your measuring cups! Keep using them to measure fluid ounces too. But when a recipe lists the ingredients by weight (straight up ounces), you need to use a scale, even for the liquids. Even for recipes as low key as chocolate chip cookies.
Plenty of pastry chefs will say you have to buy a scale in order to bake successfully, a goofy demand considering most recipes call for sugar by the cup. Instead, whether or not you should invest twenty five bucks in a scale depends on how often you find yourself trying to convert recipes from ounces to cups. If that’s something you’ve never had to do, you’ll live and do well without one.
But if your favorite cookbooks and websites use weight measurements, or if you spend any time at all Googling things like how many ounces are in a cup of flour, you may want to think about it. Especially considering the number one search result for that question is the wrong answer.
