The science of cooking has come a long way in the past century, in part because measuring has become much more standardized and accurate. Until about 100 years ago, most recipes didn’t call for specific measures. Even when they did, this information was only moderately helpful because home cooks did not own standardized measuring cups.
In colonial America, a recipe that called for 2 cups of flour assumed the cook would have a cup she used for measuring, but there was no guarantee that the cup used in Thomas Jefferson’s kitchen held the same amount of flour as the cup used in George Washington’s kitchen. It wasn’t until the late 19th century that companies started to manufacture the type of standardized measuring cups and spoons we now take for granted.
So how did cooks get along without standardized measures? You might imagine that cooking before the advent of standardized measures was unreliable, but it wasn’t. That’s because the skill level of the home cook was quite high and the range of recipes prepared was quite narrow. Cooking was a specialized task, much like needlepoint or carpentry. It wasn’t something you learned by reading a book. You learned from watching someone else (usually your mother). In addition, cooking was highly repetitive. You mastered a small set of recipes that relied on local ingredients and local traditions, and you made those same recipes over and over and over.
The publication of "The Boston Cooking-School Cook Book", written in 1896 by Fannie Merritt Farmer (yes, that Fannie Farmer), marked a watershed moment in American cooking. Recipes in this best-selling book called for standardized measurements and future recipe writers followed suit. In the introduction, Fannie Farmer exhorted her readers to purchase true measuring cups: “Correct measurements are absolutely necessary to insure the best results. Good judgment, with experience, has taught some to measure by sight; but the majority need definite guides.”
Fannie Farmer was a true believer in the power of science to improve home cooking. What she didn’t see coming was the decline in experience that would make measurement by sight all but impossible for 99 percent of home cooks today. In addition, the explosion of recipe choices has meant that even experienced cooks find themselves preparing new recipes all the time. We source ingredients and recipes from around the world. For this model to work, accurate measurement is essential. How else would the modern American cook be able to make dishes as diverse as curries, stir-fries, tamales, and tiramisù?
MEASURING IS NOT AS SIMPLE AS IT SOUNDS
It’s easy to understand that measuring matters, but many modern cooks don’t comprehend that how they measure is just as important as the act of measuring itself. What’s the point of measuring if you don’t measure correctly?
Now, you might be thinking that it can’t be that hard to measure, especially if you’re using standardized measuring cups. But we ran the following experiment in the test kitchen to prove otherwise. We asked 18 cooks, all professionally trained, to measure 1 cup of flour using the same standardized measuring cup. We then weighed the flour they measured to see how much flour was in their “1 cup.” Because of variations in measuring techniques, the weights of flour they obtained varied by 13 percent.
What makes this especially surprising is the fact that everyone in our test kitchen uses the same method for measuring flour. We dip the measuring cup into a container of flour and then sweep off the excess with a butter knife or icing spatula. (This method is known as the dip-and-sweep method.) If you measure flour by spooning the flour into a measuring cup, a technique that aerates the flour as you go, you might end up with 20 to 25 percent less flour.
So why would 18 cooks all using the same method for measuring flour get different results? We realized that how each person dips the cup into the flour affects the amount of flour that fits within. A forceful dip packs more flour into the cup than a gentle one.
PROFESSIONALS PREFER WEIGHT TO VOLUME
Recipes written for home cooks rely on volume (teaspoons, tablespoons, cups) for measurement. Recipes written for professionals generally list ingredients by weight. That’s because weight involves no chance for operator error. Assuming the scale has been properly calibrated, 8 ounces of flour is 8 ounces of flour no matter how the flour is handled. For this reason, we generally supply weights for key ingredients when we write our recipes. We always specify the weight of meat because the cooking time for a 12-ounce pork chop is different from the cooking time for an 8-ounce pork chop. Likewise, we list weights for fruits and vegetables when they are used in large quantity. Calling for 2 pounds of russet potatoes in a mashed potato recipe is much more accurate than calling for four russet potatoes, which can weigh as little as 7 ounces each (1¾ pounds total) or as much as 10 ounces each (2½ pounds total).
Weight is especially important when baking, which is why our recipes include both volume and weight measures for key baking ingredients, as does the chart below.
CONVERSIONS FOR INGREDIENTS COMMONLY USED IN BAKING
Ingredient: 1 cup all-purpose flour
Ounces: 5
Grams: 142
Ingredient: 1 cup cake flour
Ounces: 4
Grams: 113
Ingredient: 1 cup whole-wheat flour
Ounces: 5½
Grams: 156
Ingredient: 1 cup granulated (white) sugar
Ounces: 7
Grams: 198
Ingredient: 1 cup packed brown sugar (light or dark)
Ounces: 7
Grams: 198
Ingredient: 1 cup confectioners sugar
Ounces: 4
Grams: 113
Ingredient: 1 cup cocoa powder
Ounces: 3
Grams: 85
Ingredient: 8 tablespoons butter (1 stick, or ½ cup)
Ounces: 4
Grams: 113
A WORD ABOUT METRIC CONVERSIONS
Cooks using our recipes outside of the United States should also be aware that key ingredients are not always the same. Flour milled in the United Kingdom and elsewhere will feel and taste different from flour milled in the United States.
We recommend that all cooks, especially those using ingredients purchased outside of the United States, rely on their instincts when making our recipes. Refer to the visual cues provided. If the bread dough hasn’t “come together in a ball,” as described, you may need to add more flour—even if the recipe doesn’t tell you so. You be the judge.
DRY VERSUS LIQUID MEASURES
Even though weight is a more accurate way to measure than volume, we know that most cooks will rely on measuring cups and spoons, not scales, when cooking. That’s fine, but there are ways to increase your accuracy when using volume measures.
First and foremost, you should own and use three sets of measuring tools—dry measuring cups, liquid measuring cups, and measuring spoons. Here’s what you need to know about each type of tool.
DRY MEASURING CUPS are generally made of metal or plastic and have long handles and flat tops that make it easy to sweep off excess flour or sugar. We recommend that you buy a set that includes 2⁄3- and ¾-cup measures as well as the standard ¼-, 1⁄3-, ½-, and 1-cup measures. Measure all dry ingredients (flour, sugar, chopped vegetables, herbs, etc.) in these cups. Don’t measure liquid ingredients in these cups; you won’t completely fill the cup (to prevent spills) or you will fill the cup and then spill some of the liquid as you work. Either way, the end result is a recipe with too little liquid.
LIQUID MEASURING CUPS are generally made of glass or plastic and are clear with markings on the side. All liquid measuring cups have handles and pour spouts. Because you’re not filling the cup to the brim, liquids won’t spill as you work.
Still not convinced you need both dry and liquid measuring cups? We ran another experiment to convince skeptics in the kitchen—and you. In addition to asking 18 cooks in our kitchen to measure 1 cup of flour with a dry measuring cup (where we found results varied by 13 percent), we asked the same cooks to measure 1 cup of flour in a liquid measuring cup and found the variation in the weight of the flour actually contained in the liquid measuring cup jumped to 26 percent. That’s because there’s no way to level off the flour in a liquid measuring cup.
Likewise, we asked these cooks to measure 1 cup of water (which should weigh 8.35 ounces) in both dry and liquid measuring cups. The measurements in the liquid measuring cups varied by 10 percent, based on different interpretations of when the water had reached the 1-cup marking. (To fill a liquid measuring cup we recommend placing it on the counter, bending down so that the cup’s markings are at eye level, and then pouring liquid until the meniscus reaches the desired marking.) The measurements of water in the dry measuring cups varied much more—a whopping 23 percent.
The moral of the story: Measuring by weight is more accurate than measuring by volume, but if you use the right type of volume measure you can reduce the error rate.
In addition to dry measuring cups and liquid measuring cups, you need measuring spoons.
MEASURING SPOONS have handles and flat tops like dry measuring cups, so you can sweep off excess salt, spices, and other dry ingredients. These spoons are also used to measure small amounts of liquid. (You can’t measure a tablespoon of soy sauce in a liquid measuring cup.) Yes, the liquid might spill, but there’s really no other choice; work carefully and make sure to fill measuring spoons to the rim. We like oval rather than round spoons because they are easier to dip into narrow spice jars. You should own several sets of measuring spoons with a full complement of sizes—usually 1 tablespoon, 1 teaspoon, ½ teaspoon, ¼ teaspoon, and 1⁄8 teaspoon.
And memorize this now: 1 tablespoon equals 3 teaspoons. Forget this fact and you will invariably make mistakes when trying to scale recipes up or down. It also helps to remember that 4 tablespoons equal ¼ cup.
By the editors at America’s Test Kitchen and Guy Crosby in "The Science of Good Cooking", USA, 2012. Digitized, adapted and illustrated to be posted by Leopoldo Costa.