Are your eggs still good enough to use beyond the expiry date listed on the package? Expiry dates on egg packages are rough guidelines and they represent very cautious estimates. I’ve used eggs up to one month after their expiry dates with no ill effects, but I always apply this simple test first.
How to Test an Egg for Freshness
Bad eggs will usually float. Place your eggs in a bowl of water. If they float, get rid of them. If they lay flat, they should be good. If they sink but stand up on their pointy ends, use them right away – they’re close to end of life but still good for baking.
The water test is quite accurate, but it’s not a 100% guarantee; if you’re unsure about your eggs, crack them one by one into a separate bowl rather than dumping them all in with your other baking ingredients so that you don’t ruin the whole batch if you have a bad egg.
Four Signs of a Bad Egg
Never use an egg if:
- There are cracks in the shell (this allows bacteria to enter)
- It floats in water
- It smells terrible when cracked (like sulfur)
- The white has turned greenish, pinkish, or black
Why Bad Eggs Float
Eggshells are porous, and as eggs lose their freshness, the yolk and white decrease while the amount of air inside the shell increases. This makes old eggs less dense than water, so they float to the top. Eggs that are nearing the end of their freshness stand up on their heads due to air pockets within their shells.
If an egg’s shell has been cracked, bacteria may also enter and become metabolically active, which creates gas inside the egg that further reduces its density.
For more on eggs, see Nutrition – Battery Cage vs. Free Range Eggs and A Guide to Egg Labels: Free Range, Organic, and Omega-3.
For a full list of food articles, see the main Food and Nutrition page.
- Geiger, B. (22 January 2010). “A Bad Egg.” Fine Cooking – Food Science. FineCooking.com.
- Stradley, L. (2004). “Why Do Some Eggs Float? – Fresh Eggs vs. Old Eggs.” What’s Cooking America. WhatsCookingAmerica.net.
- The George Mateljan Foundation. (2014). “How Can I Tell Whether an Egg Is Bad Both Before and After Cracking It?” The World’s Healthiest Foods. WHFoods.org.