The following is excerpted from Lucky Peach’s newest book, All About Eggs: Everything We Know About the World’s Most Important Food, in bookstores April 4. Read our interview with the book’s queen egg, Rachel Khong.
Here are four ways to tell if your egg is fresh:
Break it open and look at the white. If it’s cloudy, it’s fresh! If it’s clear, it’s still okay to eat. If it looks a little pinkish, it’s bad (unless it’s a tinamou egg!). Look at the yolk. If it’s sits up and looks perky, it’s fresh! (If it flattens out, it’s not that fresh.) Look for the chalazae, the two ropey, goopy strands on either side of the yolk that keep it centered. When they’re visible, the egg is fresh. When they’re hard to find, the egg is not as fresh.
Drop it into a glass bowl full of water. As an egg gets older, the water inside it evaporates. That water is replaced by air—or, in the case of a rotting egg, smelly gases. If it sinks and lies horizontally at the bottom of the bowl, it’s very fresh—one to three days old. If it sinks, but bobs or stands diagonally, it’s quite fresh—about one week old. If it sinks, but stands vertically, it’s pretty fresh—about two weeks old. (This is a good age for hard-boiling.) If it floats, it’s a month old or older. It’s not only not fresh, it’s bad. Don’t eat this egg!
Shake the egg near your ear. If you don’t feel or hear any movement, the egg is fresh. If you feel or hear the egg moving around inside, it’s bad!
Hold it up to the light. Fresh eggs are transparent in the center; old eggs are transparent at the ends!
Reprinted from All About Eggs: Everything We Know About the World’s Most Important Food. Copyright © 2017 by Lucky Peach, LLC. Photographs and illustrations copyright © 2017 by Tamara Shopsin and Jason Fulford. Published by Clarkson Potter, an imprint of Penguin Random House, LLC.