A caller on a recent episode of the Milk Street Radio podcast presented a cooking conundrum. She made a roux using “equal parts of vegetable oil and flour,” but after cooking her gumbo, there was a thick layer of oil left at the top of the dish. What went wrong? Hosts Christopher Kimball and Sara Moulton asked how she was measuring flour and the other ingredients, and the caller said that she had used 3/4 of a cup of both oil and flour – measuring them by volume.

And that’s why her roux didn’t come out properly. Instead of using a standard liquid measuring cup, the caller should have used a scale and measured everything by weight. She would have found that she needed about twice as much flour for it to properly absorb that much oil. If she had measured everything by weight, she would have had the proper ratio in her roux, and a much more delicious gumbo.

Too many recipes – especially those you might find in older cookbooks or in some corners of the Internet – don’t provide measurements by weight. And it’s too easy to forget that a cup of oil isn’t the same thing as a cup of flour. Even worse, a recent article in the Los Angeles Times points out that there’s no standard measurement for what that cup of flour should weigh. While the New York Times typically uses 128 grams, AllRecipes.com goes with 136 grams, and Cook’s Illustrated with 142 grams. Without a standard set of measurements, the home cook can either follow the recipe blindly and hope it comes out right, or guess that the amount they’re accustomed to using won’t change the end result.

The reality is that unless you’re cooking for a crowd, the differences between those measurements are minor. Also, even if you are measuring flour with a well-calibrated scale, other factors may affect how much of it you’ll need. That’s why it’s so important to cook with your senses. If you’re making a bread dough and it feels too wet, add a little more flour to make it easier to knead. If it’s a very dry day, you might need a little more water to balance out the flour you’ve already added.

For other ingredients, especially salt, it’s important to taste your dish to see if it has the right amount of the ingredient. In a future blog, I’ll explain why a teaspoon of salt can lead to different results depending on what type of salt you’re using, and even which brand. But for flour, just be sure you’re weighing out the amount you need, or like the Milk Street caller, you’ll roux the day your gumbo was (sorry, folks) … roux-ined.

What I Ate: Avocado toast with feta on toasted sourdough