Egg freshness and boiling times: how to test and cook eggs right

Eggs are the most flexible ingredient in the kitchen, which is why a box often sits in the fridge for weeks. Then the date on the carton has passed and you wonder whether the eggs are still fine. Freshness can be checked without guessing, and boiling times are easy to remember once they are written down clearly.

The best before date for eggs is at most 28 days from laying, so the date on the box tells you fairly precisely how old the eggs are. Best before refers to quality rather than an automatic ban, but with eggs it is still worth checking the condition before use.

The water test tells you the age in seconds

Fill a glass or bowl with cold water and lower the egg in gently. A fresh egg sinks and lies flat on its side. An older egg stands upright on the bottom, because moisture has evaporated and the air cell inside has grown. An egg that floats belongs in the bin.

The test works because the shell is slightly porous. Over time water leaves the egg and air takes its place, so the egg gets lighter. An egg that stands upright is still usable, but cook it soon and preferably hard boiled or fried.

Other signs worth checking

Cracked into a plate, a fresh egg holds together: the yolk sits high and the white stays tight around it. An older egg has a white that spreads out and looks watery. The decisive sign is smell, and a sharp or sulphurous smell means the egg goes in the bin.

If the shell is cracked, sticky or mouldy, skip the egg even when the date is still valid. Bacteria get in through a crack, and that is not worth risking in food for small children, pregnant people or older family members.

Store eggs in the fridge at a steady temperature

At home eggs keep best in the fridge in their own carton, protected from odours and knocks. Avoid the door shelf, where the temperature swings every time the fridge is opened. Aim for a fridge temperature of about +4 to +6 degrees.

Do not wash eggs before storing them. The shell has a natural protective layer, and washing removes it and opens a route for bacteria. If a shell is dirty, wipe it with dry kitchen paper just before use.

Cooking is what makes an egg safe

Salmonella is destroyed by heat, and food should be cooked thoroughly to over +70 degrees. In practice a hard boiled or fully fried egg is therefore safe. For dishes with raw egg, such as homemade mayonnaise, use fresh eggs and serve straight away.

A boiled egg is also a handy source of protein, with about 7 grams in a medium egg. The same goes for egg based dishes such as North African Shakshuka with Chickpeas and Eggs, which works as well for dinner as for the next day's lunch box.

In short

Test a doubtful egg in cold water, trust your nose, and boil a medium egg for 3, 6 or 9 minutes depending on the yolk you want. Keep eggs in the fridge in their carton and they stay good through the whole date.