You lower an egg into a bowl of water, and instead of resting on the bottom, it rises toward the surface. Does that mean breakfast belongs in the trash?
Not necessarily. A floating egg usually has an enlarged air pocket, which is associated with age and declining quality. Floating alone does not prove that an egg is spoiled.
But the opposite is just as important: an egg that sinks is not guaranteed to be safe. The float test cannot tell you whether an egg contains harmful bacteria.
Before cooking, pay more attention to how the egg has been stored, how long you have had it, whether the shell is intact, and what you notice after cracking it. Then handle and cook it safely.
Why an egg starts to float
An egg has an air cell, usually at its larger end. As the egg ages, moisture and gases move through tiny pores in the shell, and the air cell generally grows.
Eventually, the air pocket may become large enough to make the egg buoyant.
Think of floating as a clue about the egg’s physical condition, not a test for germs. Storage conditions and shell characteristics also affect how quickly moisture is lost, so the result is not a precise calendar.
An egg lying flat on the bottom is generally associated with a smaller air cell. An egg that tilts upward or stands on its end has a larger one. Neither position tells you exactly how many days old it is.
Adding salt makes the test even less useful. Salt changes the density of the water and can make an egg float regardless of its age.
Freshness, spoilage, and safety are different questions
These words often get used as though they mean the same thing.
Freshness describes qualities such as a thick white and a rounded yolk. As an egg ages, its white may spread more and its yolk may become flatter.
Spoilage means the egg has deteriorated in a way that makes it unsuitable to eat. An unpleasant smell or abnormal appearance can be warning signs.
Food safety includes hazards you cannot reliably detect with your senses. Salmonella can be present in an egg without making it look or smell obviously spoiled.
That is why an older, properly refrigerated egg can still be usable, while a seemingly fresh egg still needs safe handling and cooking. A water test does not resolve those separate questions.
Start with the storage history
Before trying another kitchen test, ask yourself:
- Were the eggs sold refrigerated?
- Did you put them in the refrigerator promptly?
- Have they stayed cold?
- Do you know approximately when you bought them?
- Were they left on a counter, in a warm car, or out during a power outage?
For the refrigerated shell eggs commonly sold in the United States, keep your refrigerator at 40°F or below.
Do not let a sinking result override a known storage problem. An egg can remain heavy enough to sink even after unsafe handling.
If you find a carton and genuinely cannot establish whether it has been kept safely, the float test cannot supply that missing history. Discard uncertain eggs rather than trying to earn reassurance from the bowl.
How long can refrigerated eggs be kept?
USDA guidance allows three to five weeks of refrigerator storage for raw shell eggs. FDA recommends using them within three weeks for best quality.
Those recommendations address different things. Best quality may decline before a properly stored egg reaches the end of its usual storage range.
This does not mean every egg is safe for five weeks regardless of what happened to it. The guidance assumes appropriate refrigeration and handling.
Writing the purchase date on the carton can help. Keep the eggs in their original carton so the dates and product information stay with them.
Use older cartons first, and avoid mixing eggs from several purchases into one undated container. A simple storage record is more useful than repeatedly testing whether individual eggs float.
What do the carton dates mean?
A sell-by date helps stores manage stock. It is not the same thing as a laboratory finding that an egg becomes unsafe at midnight.
USDA says to buy eggs before the sell-by or expiration date on the carton. Properly refrigerated eggs may remain usable after the sell-by date within the recommended home-storage period.
Cartons bearing the USDA grade shield also carry a three-digit pack-date code. It identifies the day of the year the eggs were processed and packaged, rather than necessarily the day the hen laid them.
For example, 001 means January 1.
You do not need to decode every carton to prepare breakfast safely. Keep the original packaging, note when you bought it, and combine the label information with storage history. Do not treat either a date or a float result as a guarantee.
Check the shell before cracking
Choose eggs with clean, uncracked shells when shopping. Open the carton and look before placing it in your cart.
At home, set aside any egg that is leaking or has an unexplained crack. Bacteria can enter through shell damage. If you do not know when or how it cracked, discarding it is the cautious choice.
A crack that occurs during hard-boiling is a different situation from finding a damaged raw egg that has been sitting in a carton. USDA says eggs that crack during hard cooking are safe.
Do not try to repair a suspicious egg by washing it, boiling it longer, or choosing a recipe with strong flavors.
The intact eggs in the carton should still be evaluated according to their own condition and storage history. One damaged shell does not make the float test a useful verdict on the others.
Crack questionable eggs into a separate bowl
For an egg that has been properly stored but seems older, USDA recommends checking its odor and appearance after opening.
A separate small bowl helps keep a spoiled egg out of an otherwise usable batter or skillet.
- Check the storage history and shell first. Do not proceed with an egg you already have reason to discard.
- Crack one egg into a clean bowl.
- Look for abnormal discoloration or other obvious deterioration.
- Discard it if it has an unpleasant, rotten odor.
- If it appears normal and its storage history is acceptable, use it with appropriate cooking precautions.
Do not taste raw egg to decide whether it is good.
A normal smell is reassuring about obvious spoilage, but it cannot rule out Salmonella. This check supplements safe storage and cooking; it does not replace them.
Normal features that can look surprising
Not every unusual-looking detail means an egg is bad.
A cloudy white can be a sign of freshness. A clearer, thinner white may reflect aging rather than spoilage by itself.
The white, twisted strands attached near the yolk are called chalazae. They help hold the yolk in position and are a normal part of the egg.
Yolk color can vary, too. A darker orange yolk does not establish that an egg is safer than one with a paler yolk.
On the other hand, pink or iridescent egg white is a reason to discard the egg. If you cannot confidently distinguish a normal feature from abnormal deterioration, do not feel obliged to use it.
The aim is to recognize ordinary variation without turning visual inspection into a promise of safety.
You do not need to float-test every egg
The float test is optional, and it is not part of the essential safety routine.
For ordinary refrigerated store-bought eggs, you can skip it and focus on dates, storage, shell condition, and proper preparation.
Do not soak a whole carton as a cleaning step. USDA does not recommend washing commercially packaged eggs before use. Commercial washing is performed under controlled conditions; washing at home does not reproduce that process.
If you have already floated an egg, its position still tells you nothing definite about harmful bacteria. Do not use the result to extend the storage period or overlook a damaged shell.
Wash the bowl and your hands after handling raw eggs, and keep them away from ready-to-eat food.
Cook according to the dish, not the float result
For ordinary shell eggs, cook until both the white and yolk are firm. Scrambled eggs should not remain runny.
Cook casseroles and other egg dishes to 160°F, checked with a food thermometer.
A floating egg does not need a special extra cooking time, and a sinking egg does not qualify for lighter cooking. The relevant cooking guidance is the same.
Avoid trying to rescue a spoiled egg by cooking it thoroughly. Safety instructions apply to eggs that are suitable to use, not to ingredients with clear spoilage or unacceptable storage histories.
If a recipe is meant to be served with raw or undercooked egg, use pasteurized shell eggs or pasteurized egg products appropriate for that recipe. Check the package rather than assuming all shell eggs are pasteurized.
Be more cautious when cooking for someone at higher risk
Adults 65 and older, pregnant people, young children, and people with weakened immune systems are more vulnerable to serious foodborne illness.
For these groups, thoroughly cooked eggs are the safer choice. Pay particular attention to homemade dressings, mousse, eggnog, and other dishes in which egg may remain raw.
A fresh carton, a farm-fresh label, or an egg that sinks does not remove this concern.
Pasteurization is a controlled treatment designed to destroy harmful bacteria. It is different from checking freshness, and it is not something to improvise by briefly warming an egg at home.
If you need pasteurized eggs for a recipe, buy a product labeled accordingly and follow its storage and preparation instructions.
Store eggs where they stay consistently cold
Keep eggs in their carton on an interior refrigerator shelf rather than in the door. The door is exposed to temperature changes as it opens and closes.
Take out only what you need for the recipe. Avoid leaving the entire carton beside the stove throughout meal preparation.
Refrigerated eggs should not sit out for more than two hours, or one hour when temperatures are above 90°F.
For a picnic or long trip, use a cooler with enough ice or frozen packs to maintain a safe temperature.
These habits are more protective than repeatedly checking whether the air pocket has grown. Once an egg has been mishandled, putting it back in the refrigerator does not erase that history.
Remember that cooking starts a different storage clock
Hard-boiling does not make eggs last indefinitely.
Refrigerate hard-cooked eggs and use them within one week, whether peeled or still in the shell. Do not apply the three-to-five-week raw-egg storage range to a carton of boiled eggs.
Refrigerated cooked egg dishes generally keep for three to four days. Labeling leftovers with the cooking date makes this easier to track.
If you need to freeze raw eggs before they become too old, do not freeze them in their shells. Crack suitable eggs and beat the whites and yolks together before freezing in an appropriate container.
Freezing preserves food; it does not rescue eggs that should already be discarded.
A useful decision before breakfast
If an egg floats, pause and review the facts. Has it stayed refrigerated? Is it within the recommended storage period? Is the shell intact? Does it look and smell normal after cracking?
If the storage history is unacceptable, the shell is suspicious, or the egg shows spoilage, discard it. If it has been properly handled and remains suitable to use, floating alone is not a reason it must go in the trash.
The float test offers a clue about the air pocket. Safe storage, sensible inspection, and proper cooking tell you much more about whether the egg belongs in your meal.
For more practical safety checks, read how to prep raw chicken safely and what to check before drinking grapefruit juice with your medicines. For a very different kind of surprise, there’s also this Navy change-of-command story.
