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).
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.
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.
Carefully lower your eggs into fresh cold water using a spoon (you can do this in the pan if you're about to boil them). If the eggs stay at the bottom they're fresh; if the eggs float, however, they're stale and best avoided.
How Can You Tell If Hard-Boiled Eggs Are Bad? The best way to test if your eggs are still good after you've boiled them is, again, the smell test. Basically, you'll notice the smell is off if an egg is starting to go bad. This is true for raw eggs and it's true for boiled eggs—the funk doesn't lie.
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.
Always make sure to dispose of hard-boiled eggs once they have been left out for too long. Once they are cooked, they'll last for about one week regardless of the storage method.
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.
Gently drop one egg into the glass, and observe where it settles. If the egg sinks to the bottom and lays on its side, it should be fresh and ready to eat. If it floats all the way to the top, the egg may be spoiled.
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.
Hard-boiled eggs, peeled or unpeeled, are safe to eat up to seven days or one full week after they were cooked. To make sure they stay fresh, allow the cooked eggs cool a bit, and then store them in a sealed container in the refrigerator.
Symptoms usually begin 6 hours to 6 days after infection and last 4 to 7 days. Most people recover without antibiotic treatment. Antibiotics are needed only for patients who are very ill or at risk of becoming very ill. People who have diarrhea should drink extra fluids.
According to the Food and Drug Administration, you can keep hard-cooked eggs in the refrigerator for up to seven days after they have been cooked. 1 (Here's the best way to make them.) And it doesn't matter whether the eggs are already peeled or still in the shell. Either way, they will last for a week.
Hard-cooked eggs, which have been quickly cooled and placed in the refrigerator in their shells should be consumed within seven days. Peeled hard-cooked eggs stored in the refrigerator should be consumed within 48 hours due to the moist egg white surface being exposed and the potential of microorganism growth.
A quick test for freshness is to check if the raw egg in the shell sinks in a basin of water. Fresh eggs stay at the bottom of the bowl while stale eggs stand on end or float because of the large air cell. Other factors such as a weak shell and fine cracks can also cause the egg to float.
Crack the egg into a bowl and examine it for an off-odor or unusual appearance before deciding to use or discard it. A spoiled egg will have an unpleasant odor when you break open the shell, either when raw or cooked." If the egg sinks and stands up, then it's not very fresh but still safe to eat.
Many gardeners use eggs in the garden to boost soil nutrients. Try putting eggshells in your compost. You can also plant eggshells or a whole egg in the hole before planting tomato plants. I love eggs.
Eggs are a potent source of calcium, phosphorus, potassium, and nitrogen that are required by plants for healthy and robust growth. When you bury a whole egg in a planting hole, it takes a while to decompose and acts as a slow-release fertilizer that gets leached into the soil, thus benefitting the plant growth.