The most reliable sign that a chicken egg is rotten is an unmistakably bad odor after you crack it open. Before cracking, discard eggs with leaking or badly cracked shells, visible mold, or a suspicious storage history. The float test can estimate an egg’s age, but it cannot prove that an egg is spoiled—or safe.
When you are unsure, crack the egg into a small bowl by itself rather than directly into your recipe. Check the smell and appearance, then discard it without tasting if anything seems wrong. Remember that even a clean, fresh-looking egg can contain Salmonella, so safe refrigeration, handling, and cooking matter whether an egg passes every freshness check or not.
Quick guide: should you keep or discard the egg?
| What you notice | What it means | What to do |
|---|---|---|
| Strong sulfurous, putrid, or otherwise unpleasant odor | Spoilage | Discard the egg and clean the bowl and nearby surfaces. |
| Pink or iridescent egg white | USDA identifies this as bacterial spoilage | Discard it. Do not taste it. |
| Leaking shell, major crack, mold, or slimy contamination | The shell barrier is compromised | Discard it. |
| Egg floats in water but has an intact shell | The air cell has enlarged as the egg aged | Do not call it rotten based on floating alone; crack it separately and inspect. |
| Thin white or flatter yolk, with no bad odor or unusual color | Lower quality and an older egg | Use only if its storage history is safe and cook it thoroughly. |
| Cloudy white, small blood spot, or twisted white cords | Usually normal; cloudy whites often indicate a very fresh egg | Not a spoilage sign by itself. |
| Unknown storage history or unsafe time above refrigeration temperature | Safety cannot be determined by smell or appearance | When in doubt, throw it out. |
How to tell if a chicken egg is rotten: four checks
1. Start with the storage history
Before using any test, ask where the egg came from, when it was collected or purchased, whether it was washed, and how it was stored. A perfect-looking egg with an unknown or unsafe temperature history should not be rescued by a float test or sniff test.
For commercially purchased eggs in the United States, the USDA recommends prompt refrigeration and says raw shell eggs generally keep for three to five weeks in the refrigerator. The FDA recommends keeping the refrigerator at 40°F (4°C) or below and using eggs within three weeks for best quality. Keep refrigerated eggs in their carton in the main compartment, not in the warmer refrigerator door.
Refrigerated eggs should not remain at room temperature for more than two hours—or more than one hour when the temperature is above 90°F. After a power outage, FDA guidance says to discard refrigerated perishables, including eggs, that have been above 40°F for four hours or longer. Appearance and odor cannot reliably rule out harmful bacteria after a temperature failure.
Home-flock eggs require consistent collection and handling records. Our guide to collecting, washing, and storing fresh eggs safely covers nest-box collection, dry cleaning, when washing is necessary, refrigeration, carton labeling, and rotation.
2. Inspect the shell before cracking
Check the entire shell under good light. Discard an egg that is leaking, visibly moldy, or badly cracked. Cracks give bacteria a route through the shell, and a hairline crack may be easier to see when the egg is candled. Do not use a dirty kitchen towel or shared sponge to wipe multiple eggs; that can spread contamination from one shell to another.
- Discard: leaking eggs, shells with obvious mold or slimy residue, and eggs cracked before you found them.
- Use promptly and only when appropriate: if a clean egg cracks accidentally during handling, transfer it to a clean covered container, refrigerate it, and use it within two days in a thoroughly cooked dish, following USDA guidance.
- Do not judge by shell color: white, brown, blue, olive, and speckled shells are normal breed traits, not freshness indicators.
Frequent collection and clean, dry nesting material reduce soiling and breakage. See our nest-box guide and comparison of nest pads for chicken nesting boxes for setup ideas.
3. Understand what the float test actually tells you
Place the uncracked egg gently in a bowl of cool water deep enough to cover it. As an egg ages, moisture and carbon dioxide escape through shell pores and its air cell grows. That change affects buoyancy:
- Lies flat on the bottom: generally a relatively fresh egg with a small air cell.
- Stands upright on the bottom: an older egg with a larger air cell.
- Floats: an older, lower-quality egg whose air cell is large enough to make it buoyant.
According to the USDA, a floating egg may still be perfectly safe to use. Floating is a reason to evaluate the egg carefully—not an automatic “rotten” verdict. It is equally important that sinking does not certify safety. Water does not reveal Salmonella, and the test does not reverse an unsafe storage history.
Dry the shell after testing and avoid leaving eggs submerged. If you already know an egg was stored improperly, discard it rather than conducting more tests. The safest rule is simple: use storage history to judge safety and the float test only as a rough quality clue.
4. Crack it into a separate bowl and use your senses
Crack one questionable egg into a clean, small bowl before adding it to other ingredients. A spoiled egg usually announces itself with an offensive odor immediately after the shell is opened. The smell may be noticeable whether the egg is raw or cooked. Do not lean extremely close or taste the egg; normal kitchen distance is enough.
Discard the egg if the white is pink or iridescent, if you see obvious mold, or if the contents look unusually discolored and smell wrong. Transfer the discarded egg into a closed trash or compost container that animals cannot access, then wash the bowl, utensils, counter, and your hands with hot, soapy water.
Normal egg features that are not signs of rot
Eggs vary naturally. Some harmless features look strange if you have only seen uniform supermarket eggs:
- Cloudy egg white: USDA guidance says cloudiness is a sign of a very fresh egg because carbon dioxide has not yet escaped.
- A small blood spot: usually comes from a tiny blood vessel rupturing during egg formation. It does not mean the egg is fertilized or spoiled.
- White rope-like strands: the chalazae help hold the yolk in place and are normal.
- Dark or pale yolk: yolk color is strongly influenced by the hen’s diet. Our chicken feeding guide explains balanced feed and common dietary influences.
- Thin white and flatter yolk: usually indicate age and declining quality, not spoilage by themselves.
- Green ring around a hard-cooked yolk: often results from overcooking or iron in the cooking water and is not the same as a spoiled raw egg.
- Odd shell texture or a soft shell: this is a flock-health or shell-formation issue rather than proof that the contents are rotten. See what causes rubbery or soft-shell eggs.
Can candling tell whether an egg is rotten?
Candling can reveal shell cracks, the approximate size of the air cell, the yolk outline, and some internal defects without opening the egg. In a dark room, hold the large end near a bright egg candler and rotate the egg gently. An older egg usually has a larger air cell and a more visible, mobile yolk because the white has thinned.
Candling is useful for grading quality, but it cannot certify an egg as pathogen-free. It also takes practice: the natural color and thickness of dark or heavily pigmented shells make details harder to see. When safety or spoilage is uncertain, the storage history and separate-bowl crack test remain more useful.
Do not confuse table-egg candling with checking a developing fertile egg. Incubated eggs require different handling; our 21-day chicken egg incubation guide explains appropriate candling points for hatching eggs.
Why the shake test is not recommended
You may see advice to hold an egg near your ear and listen for sloshing. Skip this test. Movement may indicate a thinner white in an older egg, but hearing depends on the shell, the room, and the person. It does not distinguish normal aging from spoilage and cannot detect harmful bacteria. Shaking also makes the contents less useful for judging quality after cracking.
A storage check, shell inspection, and separate-bowl crack test provide clearer information without pretending that sound is a safety measurement.
Egg storage and discard times
| Egg product | Recommended refrigerated storage |
|---|---|
| Raw shell eggs | 3–5 weeks according to USDA; FDA recommends use within 3 weeks for best quality |
| Raw whites or yolks removed from shells | 2–4 days |
| Hard-cooked eggs | 1 week |
| Cooked egg dishes | 3–4 days |
| Egg cracked accidentally into a clean container | Use within 2 days and cook thoroughly |
These time ranges assume continuous refrigeration at 40°F or below and clean handling. Label home-flock cartons with the collection date and use the oldest eggs first. If eggs were mixed without dates, use the earliest possible date rather than the most optimistic one.
Do not freeze raw eggs in their shells; expansion can crack the shell. If an egg freezes accidentally and the shell cracks, discard it. USDA advises thawing an intact accidentally frozen egg in the refrigerator and using it immediately after thawing.
Special considerations for backyard chicken eggs
Collect eggs at least daily and more often during extreme heat or freezing weather. Keep nest boxes dry, replace soiled nesting material, and discourage hens from sleeping in nests. Broken eggs and manure increase contamination pressure. Good backyard flock biosecurity also helps limit rodents, wild birds, dirty equipment, and other routes that can contaminate the coop environment.
If a hen begins laying unusually thin, misshapen, or shell-less eggs repeatedly, evaluate her nutrition, age, stress, and health rather than relying on freshness tests. Young pullets may produce irregular first eggs; our guide to when chickens start laying eggs explains what is typical during the transition.
Be cautious with room-temperature egg preservation claims. Penn State Extension’s current home-flock guidance does not recommend water glassing because historical research found it ineffective at maintaining albumen quality at room temperature and capable of changing odor and flavor. Refrigeration and evidence-based freezing methods are safer choices.
Cook and handle every egg safely
A freshness check does not replace safe cooking. Wash your hands, utensils, bowls, and counters with hot, soapy water before and after contact with raw egg. FDA guidance recommends cooking eggs until the yolk and white are firm and cooking dishes containing eggs to 160°F. For foods served raw or undercooked—such as certain dressings, eggnogs, sauces, or desserts—use pasteurized eggs or pasteurized egg products.
People at higher risk of severe foodborne illness, including young children, older adults, pregnant people, and those with weakened immune systems, should be especially careful to avoid raw or undercooked eggs.
Frequently asked questions
Is an egg bad if it floats?
Not necessarily. USDA says floating means the air cell has enlarged enough to make the egg buoyant. The egg is older and lower quality, but it may still be safe if it has been handled and refrigerated correctly. Crack it into a separate bowl and check for an off odor or unusual appearance.
Can a bad egg sink?
Yes. Sinking only suggests a smaller air cell. It does not detect Salmonella, prove a safe temperature history, or identify every form of contamination.
What does a rotten egg smell like?
A spoiled egg has a strong, unmistakably unpleasant odor often described as sulfurous or putrid. If the smell is questionable, discard the egg without tasting it.
Are watery egg whites safe?
A thinner white commonly develops as an egg ages and does not prove spoilage. Use the storage history, shell condition, odor, and overall appearance. Discard a pink or iridescent white.
Should I wash an egg before testing it?
Do not wash a clean egg just to perform a freshness test. If a home-flock egg requires wet cleaning, use an evidence-based method and refrigerate it afterward. Never soak eggs in standing wash water, which can encourage contaminants to move through shell pores.
Sources and further reading
- USDA FSIS: Shell Eggs from Farm to Table
- FDA: What You Need to Know About Egg Safety
- USDA FSIS: Is the Appearance of Eggs Related to Food Safety?
- Penn State Extension: How to Safely Handle and Store Eggs from Your Home Flock
- Penn State Extension: Proper Handling of Eggs from Hen to Consumption
This article provides general food-safety information. If you suspect foodborne illness, contact a healthcare professional and your local public-health authority.
