A floating egg is not automatically spoiled, and a sinking egg is not guaranteed safe. As an egg ages, its air cell can grow and increase buoyancy. The UK Food Standards Agency says the water test indicates age rather than microbiological safety.
- Read the label and storage advice
- Check the shell
- Treat buoyancy as an age clue
- Do not use damaged or uncertain eggs
What floating and sinking actually tell you
Floating can mean the air cell has enlarged. US USDA guidance says a floating egg may be lower quality without necessarily being unsafe to use. The reverse is just as important: an egg that stays on the bottom has not passed a bacterial test.
The popular rule ‘float equals dangerous, sink equals safe raw’ therefore does not hold. Water cannot reveal how the egg was stored or which bacteria might be present.
A better decision sequence
Read the date label and storage instructions for the market where you bought the eggs. Check whether a product sold refrigerated spent an extended time warm. Do not use a water test to approve a cracked or leaking shell.
Breaking an egg into a separate bowl may reveal an obvious off smell or unusual appearance, but normal appearance is not proof of safety. For uncooked egg dishes or people at higher risk, follow local public-health advice and any individual medical instructions.
A worked example
If an egg from your refrigerator floats, do not decide from that result alone. Check its label, storage history and shell. If it is cracked or has an obvious abnormality, do not use it. A sinking egg is not a certificate of safety either.
Common questions
Does sinking mean it is safe to eat raw?
No. Buoyancy says nothing about the presence of pathogens.
Must I discard every floating egg?
Not based on the float result alone. Check the date, storage and shell condition.
Can I still use the water test?
Only as a clue to age, not as a food-safety decision.
Official sources checked
This is general information; individual circumstances and product or agency instructions may differ.