Eggs are a kitchen staple, but they don’t last forever. The good news is that you don’t need a laboratory to figure out if an egg is still safe to eat. A few simple checks at home can tell you what you need to know. The most reliable method is the float test, but it should not be your only check. You also need to use your eyes and your nose. Here is the step-by-step process to determine if your eggs have gone bad.
Why Do Eggs Go Bad?
Eggs are porous. That means air can pass through the shell. Over time, moisture and carbon dioxide leave the egg, and air enters. This is a natural process. As the egg ages, the air cell inside gets larger. The white becomes thinner, and the yolk flattens.
Most eggs in the grocery store are not fresh from the farm. They can be several weeks old by the time you buy them. That does not mean they are bad. It just means they have a shorter shelf life once you get them home. The key is knowing how to tell the difference between an older egg that is fine to eat and one that has actually spoiled.
Step 1: Check the Expiration Date
Start with the label. The date on the carton is your first clue. In the United States, the “Sell By” date tells the store how long to display the eggs. The “Best By” or “Use By” date is the manufacturer’s suggestion for peak quality. Eggs are usually still safe to eat for a few weeks after that date if they have been stored properly.
This is not a guarantee. A date does not tell you if the egg has been handled correctly. If the carton has been left out on the counter for hours, the eggs may spoil before the date. If the eggs were refrigerated the whole time, they may last longer than the date suggests. Use the date as a starting point, not the final answer.
Step 2: The Float Test
This is the test most people know. Fill a bowl with cold water. Gently place the egg in the water. Watch what it does.
- It sinks and lies flat on its side. The egg is very fresh.
- It sinks but stands upright on one end. The egg is older but still safe to eat.
- It floats to the surface. The egg is likely spoiled.
The science is simple. The air cell inside the egg grows as the egg ages. A fresh egg has a small air cell, so it sinks. An older egg has a larger air cell, so it stands up. A bad egg has a large air cell, so it floats. The float test is reliable for judging age, but it is not perfect for judging safety. A floating egg is almost always bad, but a sinking egg is not always good. You still need to check it further.
Step 3: The Sniff Test
Your nose is a powerful tool. Crack the egg into a clean bowl. Smell it immediately. A fresh egg has almost no smell. A spoiled egg has a distinct, unpleasant sulfur odor. That smell is hydrogen sulfide gas, and it means the egg is not safe to eat.
Do not rely on the float test alone. An egg that sinks could still be rotten inside. The smell test is the most direct way to know if an egg has gone bad. If it smells bad, throw it out. Do not taste it. Cooking will not remove the toxins that cause food poisoning.
Step 4: Inspect the White and Yolk
Once the egg is cracked, look at it closely. A fresh egg has a thick, cloudy white and a firm, round yolk. The white may be slightly cloudy. That is normal. It means the egg is very fresh.
An older egg has a thinner, more watery white. The yolk may be flatter and break more easily. This is not necessarily a sign of spoilage. It just means the egg is not as fresh. The egg is still safe to eat as long as it smells fine.
Look for any pink, green, or iridescent colors in the white. Those colors are a sign of bacterial growth. If you see them, throw the egg away. A small blood spot on the yolk is not a sign of spoilage. It is a harmless defect that happens when a blood vessel breaks during formation.
Step 5: The Sound Test
This test is less common, but it can help. Hold the egg near your ear and shake it gently. A fresh egg makes almost no sound. The contents are thick and fill the shell. An older egg may make a slight sloshing sound. That is because the contents have thinned out and move around more.
A loud sloshing sound is not a reliable sign of spoilage. It only tells you the egg is older. Use this test as a secondary check, not a primary one. The smell test is more accurate.
What If You Are Unsure?
When in doubt, throw it out. This is the safest rule. Eggs are inexpensive compared to the cost of food poisoning. The symptoms of eating a bad egg include nausea, vomiting, diarrhea, and stomach cramps. These symptoms usually appear within a few hours to a day after eating.
Some people are at higher risk for severe illness from spoiled eggs. This includes pregnant women, young children, older adults, and people with weakened immune systems. For these groups, the risk is not worth it. If there is any doubt about an egg, it should be discarded.
How Long Do Eggs Actually Last?
Properly refrigerated eggs can last for several weeks. The refrigerator should be set at or below 40°F (4°C). Store eggs in their original carton on an inside shelf, not in the door. The door is the warmest part of the refrigerator, and the temperature changes every time you open it.
Fresh eggs from a farm can last for weeks if they are unwashed and stored at room temperature. But once they are washed and refrigerated, they must stay refrigerated. If you buy eggs from a store, keep them cold. If you buy eggs from a farmer, ask how they should be stored.
Hard-boiled eggs do not last as long as raw eggs. They should be eaten within one week of cooking. Peeled hard-boiled eggs should be eaten within a few days. Keep them in the refrigerator.
Can You Freeze Eggs?
Yes, but not in the shell. Freezing raw eggs in the shell can cause the shell to crack. The egg expands as it freezes, and the shell cannot handle the pressure. To freeze eggs, crack them into a bowl, whisk them together, and pour them into a freezer-safe container. They can be frozen for up to a year.
Frozen eggs are best used for baking or cooking, not for frying or poaching. The texture changes during freezing. The white becomes less firm, and the yolk becomes thicker. This is fine for scrambled eggs or baked goods.
Thaw frozen eggs in the refrigerator overnight. Do not thaw them at room temperature. Use them immediately after thawing. Do not refreeze thawed eggs.
Common Myths About Egg Freshness
There are many myths about eggs. One common myth is that brown eggs are fresher than white eggs. That is not true. The shell color depends on the breed of the hen, not the freshness. The nutritional value is the same.
Another myth is that eggs must be washed before use. In the United States, eggs are already washed before they reach the store. Washing them again at home can remove the protective coating and increase the risk of bacteria entering through the shell. Do not wash eggs before storing them.
A third myth is that a cracked egg is fine as long as it is cooked. This is risky. A cracked shell allows bacteria to enter the egg. If the egg is cracked, it should be used immediately or discarded. Do not store cracked eggs.
Frequently Asked Questions
Can you eat eggs after the expiration date?
Yes, eggs are often safe to eat for a few weeks after the date on the carton if they were stored properly in the refrigerator. Always check for smell and appearance before eating them.
Is the float test always accurate?
No, the float test is a good indicator of age but not a guarantee of safety. A sinking egg can still be spoiled, so always crack and smell the egg before using it.
What does a bad egg look like when cracked?
A bad egg has an unpleasant sulfur smell and may have pink, green, or iridescent colors in the white. Fresh eggs have a clear or slightly cloudy white and a firm yolk.
How long do hard-boiled eggs last in the fridge?
Hard-boiled eggs should be eaten within one week of cooking. Peeled hard-boiled eggs should be eaten within a few days and kept refrigerated.
