Simply fill a bowl with cold tap water and place your eggs in it. If they sink to the bottom and lay flat on one side, they are fresh and good to eat. A bad egg will float because of the large air cell that forms at its base. Any floating eggs should be thrown out.
The theory is that, as an egg ages, the air pocket inside it grows larger, buoying an old egg to the surface. But, according to Dr. Schaffner, “there is no scientific basis for the egg float test.” So experimenting to see if your egg sinks or swims is not a reliable way to measure its quality.
If the eggs sink to the bottom and lay flat on their side, they're still fresh. However, if they sink, but stand on one end at the bottom of the glass or bowl, they're not as fresh but still edible. Of course, if any eggs float to the top, they shouldn't be eaten.
If eggs sink to the bottom of a bowl of cold water and lie flat on their sides, they are very fresh. If they are less fresh but still good to eat, they will stand on one end at the bottom. If they float to the surface, they are no longer fresh enough to eat.
Information. An egg can float in water when its air cell has enlarged sufficiently to keep it buoyant. This means the egg is old, but it may be perfectly safe to use. Crack the egg into a bowl and examine it for an off-odor or unusable appearance before deciding to use or discard it.
You can eat eggs past their expiration date. Just be sure to keep your eggs egg-cellent by storing them correctly. If you don't know if an egg is good or not, you can try the float test or give it a whiff. If it doesn't pass the test, throw it away.
Old eggs should always be disposed of responsibly to avoid contamination and food-borne illnesses. You can choose to compost, feed them to animals, recycle them at local centers, or throw them in the trash. Eggs with foul odors or discoloration may be spoiled and should not be eaten.
Eggs that are "expired" might stay fresh for a few weeks after their date, but if an egg is spoiled, it should not be eaten. Spoiled eggs could be contaminated with salmonella, a bacterial infection that leads to diarrhea, vomiting, fever, and cramps.
While it's been said that means the eggs have gone bad and should be thrown out, a floating egg does not necessarily equal a bad egg. Eggs have an air cell that becomes larger as the egg ages and acts as a buoyancy aid.
As long are they are kept refrigerated at 45 °F or lower, fresh shell eggs are safe to be consumed four to five weeks beyond the carton's Julian date (the date eggs were packed).
Anyway, as the egg gets older it ends up with more gas inside and less water, and the gas is lighter than the water. Overall, this makes the egg lighter and in fact less dense than water so that a stale egg floats.
Judging the freshness of your eggs
Semi-fresh eggs: Eggs which are semi-fresh should sink to the bottom but stand up straight. Older eggs: If your egg floats higher than halfway towards the surface of the water this means it's most definitely not fresh and consumption should be avoided.
The most accurate way of testing whether your eggs have gone bad is to crack them open. If the yolk or white has any discoloration, the egg is no good. Discoloration is an indication of bacterial growth. If your eggs look good but have an off or sulfuric smell to them, they are bad.
An unwashed egg will last for 6 months or more in the refrigerator. If the fresh eggs have been washed, then the shelf life will be similar to a store bought egg - about 4-5 months.
Eggs can legally be sold up to a month after the sell-by date, after which they are indeed illegal but still very much edible for another two weeks or so, longer if they're hard-boiled and kept in the shell.
What happens if you use old eggs. If you use older eggs, the cakes will not rise as well and pavlovas will be flatter than they should be. Generally, the cakes will still work as long as you get some volume from beating, they just won't be as tall or light-as-air as they should be.
Salmonella can get on the shells of eggs. This can happen when birds lay the eggs and when eggs touch bird droppings (poop) after being laid. Touching eggs from the grocery store is not a major cause of illness because those eggs are washed before they reach stores. Salmonella can get inside eggs too.
Yes, you can freeze eggs. Eggs can be frozen for up to a year, although it is recommended to use them within 4 months for freshness. Many people find themselves being left with spare egg whites or yolks after a recipe requiring just one or the other, or even throwing out unused eggs when the box hits its expiry date.