As an egg ages, this air cell grows larger as the yolk and white further contract. Therefore, an older egg is less dense and more likely to float in boiling water. Store-bought eggs can last several weeks beyond their sell-by date or expiration date.
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.
4 minutes for slightly set yolk and set white. 5 minutes for a medium cooked firmer yolk and white. 6 minutes for hard boiled with lightly soft yolk. 8 minutes for firmly hard boiled.
This article has been viewed 1,831,784 times. To tell whether an egg is raw or hard-boiled, place it on its side and spin it. If the egg spins steadily, it's hard-boiled; if it spins slowly or wobbles, it's raw. If you can't tell, stop the egg with your finger, then take your hand away.
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.
To check if it is safe to eat, crack the egg in a bowl and check for an off-odor or unusual appearance before determining whether to use or discard. A spoiled egg has a terribly unpleasant odor when you crack it open — whether raw or cooked.
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.
The water test for egg freshness
Very fresh eggs will sink to the bottom and lay on their sides. If an egg stays at the bottom but stands on its small end, it's still acceptable to eat; just not quite as fresh.
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.
The float test works because air builds up inside the egg as it ages, increasing its buoyancy. However, an egg that floats may still be safe to eat, according to the United States Department of Agriculture (USDA).
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.
Risks of Eating Bad Eggs
Salmonella is common in eggs, whether they are good or bad. However, salmonella is cooked out of eggs with heat. As eggs go bad, they develop other types of bacteria like E. Coli that lead to severe illness.
The trick to great hard boiled eggs is not over-cooking them, which can leave a grey ring around the yolk and make their texture a bit rubbery.
If your egg has broken into the boiling water, you should find strings formed from the leaked egg white into the water or clumps of the white on the egg shell. But, don't worry, the egg is still safe to eat as long as you hard boil them.
With all that in mind, here are the cooking times for various types of boiled eggs. The times start after the water has come to a boil and you've turned off the heat. 2 minutes - The white isn't fully set and the yolk is totally raw. 4 minutes - The white is fully set, but the yolk is thick and runny.
For one to four eggs, bring the water to a rolling boil, cover the pot, and turn the heat down to its lowest setting for 12-14 minutes. For five to eight eggs, cook for 15 to 18 minutes. For nine to one dozen eggs, cook for 20 minutes.
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.
Judging the freshness of your eggs
Fresh eggs: A fresh egg will sink to the bottom of the water, with its positioning running lengthways on its side. Semi-fresh eggs: Eggs which are semi-fresh should sink to the bottom but stand up straight.
To check if it is safe to eat, crack the egg in a bowl and check for an off-odor or unusual appearance before determining whether to use or discard. A spoiled egg has a terribly unpleasant odor when you crack it open — whether raw or cooked.