How many cartons of eggs do you have in your fridge? Do you ever stock up on egg cartons at the grocery store when they're on sale and then forget you have them? We've told you all about what the code on a carton of eggs means and about the difference between brown and white eggs, so now let us fill you in on one of the coolest egg-related kitchen hacks: How to tell if eggs are fresh without cracking them open.
Yes, that code on the egg carton gives you a date, which might be the expiration date or it might be the sell-by date. Eggs tend to keep for a long time, so even if you're well past the date on the carton it's worth checking to see if the eggs are still good.
At the same time, the quality of an egg changes as the egg ages. Fresh eggs are great for any dish where the egg is the star, such as an omelette or Eggs Benedict, but older eggs are great for baking or for hard-boiled eggs. Fortunately, there's one easy way how to tell if eggs are fresh, older but still good or if they've gone bad.
How to Tell if Eggs are Fresh
To tell how fresh an egg is, use the float test.
- Fill a deep bowl, pan or large measuring cup with cold water, enough to cover an egg by an inch or two.
- Gently place the egg in the water, on the bottom of the container.
- If the egg stays on its side, it's very fresh.
- If the egg stands upright on one end, it's an older egg, but still good to eat.
- If the egg floats, it's bad and should be tossed.
The Science Behind the Float Test
There's a simple reason why bad eggs float. There's a thin membrane just inside the eggshell. Because eggshells are porous, air passes through the shell into a little air pocket between the membrane and the eggshell. As air gets into that pocket, the quality of the egg degrades. The more air inside the egg, the more buoyant the egg is and thus the more it floats. The freshest eggs don't have much air inside the shell, so they don't float.
If you don't think to test the eggs in a bowl of water before cracking them open, the other reliable way how to tell if an egg is fresh is to take a close look and smell at the raw egg.
A rotten egg will smell like it, no question. If the egg smells okay, check the egg white. Fresher eggs will have a thick, cloudy egg white that doesn't spread out. If the egg white is thin and spreads out, or if the white is clear, it's an older egg. Check the egg yolk, too. If the yolk has a rounded dome that stand-ups, it's fresh. If the yolk is flat or if it breaks easily, it's an old egg.