Do Not Use a Liquid Measuring Cup to Measure Dry Ingredients
In terms of precision, cooking is a spectrum. There are times when a glance at the eye is enough – for example, removing the frosting from a frying pan with about half a glass of wine – and there are times when accurate measurements are vital – for example when baking finicky doughs or most recipes from Serious Eats. Measuring ingredients by weight ( on a kitchen scale , for example) will give you the best, most reproducible results, but if you insist on measuring by volume, you must make sure you are using the correct cup.
You see, although both dry measuring cups (similar to spatulas) and liquid measuring cups (usually glass with lines on the sides) claim to hold a “cup,” the reality is that a dry measuring cup holds a little more. When I filled a dry cup with water, I found that it holds, on average, 10 grams more water than my liquid measuring cups. It probably won’t make a lot of difference for something like spaghetti sauce, but 10 grams of extra liquid – or 20 or 30, depending on how many cups the recipe calls for – can really ruin your baked goods, ice cream, or candy making.
Also, dry measuring cups are simply not designed to measure wet ingredients, and vice versa. The correct way to measure liquid is to place a beaker on a flat surface, pour liquid just below the line, then bend over so your eyes line up with the dividing lines, then slowly add more liquid to the bottom of the scale. The meniscus (a curved line that forms on top of the liquid due to surface tension) is flush with the line. You just can’t do that with a dry measuring cup. Not only are there no lines, but the meniscus is not visible either. Conversely, the old scoop-and-scraper dry method will not work in a wet measuring glass, as the “cup” line is below the edge of the glass. If you’re working with a really picky recipe, the scale will always be your best friend, but if you don’t have a scale or find yourself in the kitchen without one, make sure you’re using the right “cup” for the job. It can be cake or not.