In response to my article in the Washington Post about why you need a scale in your kitchen, a reader asked how to convert recipes from cups to weights and how to know whether a scale is accurate. Her questions and my answers follow, in addition to my cheat sheet of weights for the most common baking ingredients.

Q: Do I now toss out all my cookbooks & try to replicate recipes (including grandma’s) with appropriately written ones found on the Internet or in Medrich’s cookbook? How does one exchange old recipe cups for ounces or grams?

A: Please don’t toss out beloved old recipes (or books) just because they don’t have weights! There are two methods for converting recipes to weights, depending on whether a recipe is a familiar favorite or one that is new to you.

If a recipe is already a tried-and-true favorite—one that normally turns out well for you— measure with cups exactly as you usually do but then weigh each measured ingredient before you add it to the batter. Don’t use a chart in the back of a book or on the Internet for this—the idea is to capture what you actually do, but in weights. Jot your weights on the recipe. This requires extra steps only the first time you make each recipe again. You will up with a repertoire of reliable recipes with weights, and those recipes will forever be faster and easy to reproduce.

For recipes that you have never tried, use a weight chart from a credible baker or pastry chef (or my Cheat Sheet below) for ingredients other than flour. Don’t fret about slight variations (a few grams or tiny fractions of ounces) between charts for most ingredients.

Flour is a critical exception — a few extra nuts or raisins in a recipe don’t hurt a thing but too much flour can make a huge difference. There is no official agreed upon weight of flour per cup across all recipes and all cookbooks. My cup of flour weighs 4.5 ounces, while King Arthur’s weighs 4.25 ounces. People who dip and sweep may be getting 5 to 6 ounces in 1 cup. The trick is to use the same amount of flour as the cook who created the recipe!

Here’s how: if the recipe is in a book that does not include weights, read the front of the book to see if the author explains how they measured flour—whether they dip the cup into the flour and sweep it level or if they fluff the flour and then lightly spoon, or any other details. Then measure a cup of flour exactly as described and weigh it. Use that weight per cup for the recipes in that book or in any other book where the author describes measuring in the exact same way.

If you remember seeing your grandmother dip a measuring cup into the flour canister or sack—and that is probably how most grandmothers did it—or you remember her doing it a different way, then you should measure a cup of flour her way and then weigh it. Use that weight for all of her recipes!

Q: HOW DO I INSURE THE ACCURACY OF MY SCALE?

A: Check the weight of an unwrapped 4-ounce/113 gram stick of butter. If you plan to weigh small quantities, like salt and leavenings, or you just want to know that your scale is accurate in small increments, weigh some coins: 2 pennies or one nickel should weigh 5 grams. (Keep in mind that if your scale is accurate only to 5 grams, it will always round up to the nearest 5 grams: 1 penny will register 5 grams and 3 pennies will register 10 grams. Don’t let this confuse you. And don’t expect to be able to measure in 1-gram increments.)

If the scale is off, use the calibration feature—check the manual to see if has one and follow the instructions. Absent a calibration feature, return a new scale to the store. Or, regardless of age, email the manufacturer asking if they can fix it for you. They might ask you to send it to them. Do it. Sometimes they will send you a new scale!

ALICE’S CHEAT SHEET: THE WEIGHT OF COMMON BAKING INGREDIENTS

Butter: 4 ounces/113 grams per stick (thus 1 T=14 g)

Nuts: weights vary by type of nut and whether the nuts are whole or already chopped. When it comes to nuts, exact amounts are rarely critical, but it is so much easier to weigh first and chop next. Here are the weights that I use for different types of nuts:

Walnut and Pecan halves or large pieces: 3 ½ ounces/100 grams per cup, or 4 ounces/113 grams per cup if already chopped

Peanuts: 4 ounces/113 grams per cup

Whole Almonds or hazelnuts: 5 ounces/140 grams per cup, or 4 ounces/113 grams if already chopped

Pistachios: 5.33 ounces/150 grams per cup

Sugar

Granulated sugar: 7 ounces/200 grams per cup
Brown sugar (firmly packed): 7 ounces/200grams per cup
Confectioners’ sugar: 4 ounces/113 grams per cup