How to Tell If Eggs Are Bad: 7 Reliable Methods to Check Egg Freshness
Knowing how to tell if eggs are bad is crucial for food safety and avoiding unpleasant cooking experiences. Eggs can spoil before their expiration date or remain good long after, making visual inspection and simple tests essential. This comprehensive guide covers 7 proven methods to check egg freshness, from the classic float test to candling techniques. Learn how to identify bad eggs with confidence and never risk using spoiled eggs again.
1. The Float Test (Water Test)
How It Works
The float test is the most popular method for checking egg freshness because it's simple and reliable. As eggs age, the air cell inside grows larger, making them more buoyant.
Steps to Perform the Float Test
- Fill a bowl or glass with enough cold water to completely submerge an egg
- Gently place the egg in the water
- Observe how the egg behaves:
- Fresh egg: Sinks to the bottom and lies flat on its side
- Slightly old egg (1-2 weeks): Sinks but stands upright or tilts slightly
- Bad egg: Floats to the surface
Pro Tip: Use room temperature water for most accurate results. Very cold water might give false negatives for older eggs.
2. The Sniff Test
How It Works
Rotten eggs emit a distinct sulfur smell due to hydrogen sulfide gas produced as the egg decomposes. This is one of the most reliable ways to tell if an egg is bad.
How to Perform the Sniff Test
- Hold the egg close to your nose
- Take a quick sniff of the shell
- If you detect any unpleasant, sulfurous odor, the egg is bad
- For extra certainty, crack the egg into a clean bowl and smell it
Warning: If an egg smells bad when cracked, discard it immediately and wash the bowl thoroughly to prevent contamination.
3. Visual Inspection (Cracked Egg Test)
What to Look For
Examining the egg's appearance after cracking can reveal important freshness clues:
| Feature | Fresh Egg | Bad Egg |
|---|---|---|
| Yolk | Round, domed, sits high | Flat, breaks easily, may blend with white |
| Egg White | Thick, gelatinous, two distinct layers | Thin, watery, single layer |
| Color | Clear to slightly cloudy white | Pink, green, or iridescent sheen |
Did You Know? Cloudy egg whites actually indicate freshness, as the cloudiness comes from carbon dioxide that hasn't yet escaped through the shell.
4. The Shake Test
How It Works
As eggs age, the whites thin and the air cell expands, creating more movement inside the shell when shaken.
Performing the Shake Test
- Hold the egg close to your ear
- Gently shake it
- Listen carefully:
- Fresh egg: Little to no sound
- Old egg: Sloshing or watery sounds
This method isn't 100% reliable - always confirm with another test if you suspect an egg is bad.
5. The Candling Method
Traditional Egg Freshness Test
Candling involves shining a bright light through the egg to examine its interior. This method works best in a dark room.
How to Candle an Egg
- Use a bright flashlight or candling light
- Hold the light source against the large end of the egg
- Observe the contents:
- Fresh egg: Small air cell (1/8 inch), yolk shadow barely visible
- Old egg: Large air cell (1/2 inch or more), dark spots or streaks
Modern alternative: Use your smartphone's flashlight in a completely dark room for a DIY candling setup.
6. The Plate Test
Visual Spread Test
This method examines how the egg white spreads on a flat surface, indicating its thickness and freshness.
Steps for the Plate Test
- Crack the egg onto a clean, flat plate
- Observe how it behaves:
- Fresh egg: White stays compact around yolk, doesn't spread much
- Old egg: White spreads out thinly, yolk appears flat
7. The Julian Date Check
Understanding Egg Carton Dates
In the US, egg cartons typically feature two important dates:
- Expiration date: Usually 30-45 days after packing
- Julian date: 3-digit number (001-365) representing packing day
How to Use Dates for Freshness
- Find the 3-digit Julian date on the carton
- Calculate days since packing (001 = January 1)
- Eggs are typically fresh for 4-5 weeks after packing
Eggs are often still good for 2-3 weeks after the expiration date if properly refrigerated.
Additional Egg Freshness Indicators
Shell Condition
Examine the eggshell for these warning signs:
- Powdery or slimy texture
- Cracks or fractures
- Unusual spots or discoloration
Egg White pH Test
Fresh egg whites have a pH of 7.6-8.5, becoming more alkaline as they age. Use pH strips for precise measurement.
Safe Egg Handling Tips
Now that you know how to tell if eggs are bad, remember these safety practices:
- Always refrigerate eggs at 40°F (4°C) or below
- Store eggs in their original carton (not the fridge door)
- Use cracked eggs immediately (discard if unsure)
- Cook eggs thoroughly to kill potential bacteria
- When in doubt, throw it out - better safe than sorry
By combining these methods - especially the float test and sniff test - you can confidently determine egg freshness. Remember that proper storage significantly extends egg shelf life, so always keep eggs refrigerated and use them within 3-5 weeks of purchase for best quality.