How do I tell if an egg is still good?
The float test for age, the smell test for safety, and why they answer different questions.
- Difficulty
- beginner
- Time
- 5 min
- Read
- 2 min
- Safety
- warning
Short answer
Float it in water: sinks flat means fresh, stands on end means older but usually fine, floats means throw it away. Then crack it into a separate bowl and smell it — that is the actual safety check.
The float test measures age rather than safety. Eggshells are porous, so the air cell inside grows over time — a useful proxy, but the definitive answer comes from cracking it somewhere you can discard it.
Safety
Step by step
- Do the float test in a bowl of cold water.Enough water to cover the egg. Sinks and lies flat: very fresh. Sinks but stands upright: older, fine for cooking, best hard-boiled or baked. Floats: discard it.
- Understand what the test measures.The shell is porous. As an egg ages, moisture escapes and the air cell inside grows, making it more buoyant. It is a measure of age, not of whether bacteria are present.
- Crack it into a separate bowl.Always, when in doubt — never straight into the mixing bowl or the pan. One bad egg ruins a batch of ingredients if it goes in with them.
- Smell it.The definitive test. A bad egg smells strongly sulphurous and there is no ambiguity about it. If it smells at all wrong, discard it and wash the bowl.
- Look at the white.A fresh egg has a thick white that holds close to the yolk. An older one spreads thin and watery. Both are safe; the fresh one poaches and fries far better.
- Ignore harmless things.Cloudy white means very fresh. A small blood or meat spot is harmless and can be removed. A greenish ring on a hard-boiled yolk is overcooking, not spoilage.
- Use older eggs where it suits.Older eggs peel far more easily when hard-boiled, and separate more cleanly for whisking. Very fresh eggs are best for poaching and frying.
- Store them properly.In the fridge in the UK, in their box rather than the door, pointed end down. The box protects them from absorbing other smells through the porous shell.
Tips
- Cracking each egg into a cup before adding it to a bowl is a habit worth having. It costs nothing and it saves a whole mixture occasionally.
- Eggs are usually fine well past the best-before date if kept refrigerated — but do the float and smell tests rather than assuming.
- If you use a lot of eggs, write the date on the box when you buy them. Boxes get mixed up.
Questions people ask
Does the egg float test work?
It reliably indicates age — a floating egg has a large air cell and should be discarded. It does not detect bacteria, so crack it into a separate bowl and smell it as well.
Can I eat eggs past their best-before date?
Often yes, if refrigerated, but check them. Float test first, then crack into a separate bowl and smell — the smell is unmistakable if it has gone off.