Do you know a bad egg when you see one? Probably not. Unless the delicate shell is sporting a big crack down the side (likely due to mishandling, rather than age), it’s hard to tell from one egg to the next. But there is a way to test your eggs before cracking them, saving yourself from ruining a whole batch of chocolate chip cookie dough. First, here are two things that are important to know.
Do eggs expire?
There’s a big difference between expiration and “best-by” dates. Strict expiry dates are reserved for foods where the composition and nutritional value are compromised after the prescribed time.
Best-by dates are the anticipated amount of time that a food will maintain its freshness, taste, and nutritional value, which is up to 90 days after packaging when the item is properly stored.
A major health risk associated with eggs is Salmonella, a harmful bacteria that can cause food poisoning. Salmonella is often found on the outside of the shell, and can sometimes be in the egg itself. Buy graded eggs (look for the maple leaf symbol on the carton), which have been inspected for cracks, cleanliness, and properly stored, to reduce risk.
Do eggs have to be refrigerated?
In general, eggs have a relatively long shelf life. This is due to the protective layer that coats them, preventing any bacteria or dirt from getting through the pores of the egg shell. In Canada, eggs undergo thorough washing that removes this layer, so they need to be refrigerated to prevent harmful bacteria from growing. In many other countries in Europe and South America, this layer isn’t washed off, which is why their eggs are often sold unrefrigerated.
How to tell if an egg is still good
There are several ways to determine if it’s time to toss your eggs into the compost bin.
Check for a cloudy egg white
Fresh, new eggs will have bright orange yolks and thick, cloudy whites that closely surround the yolk. Old eggs won’t stay in a nice little package when you poach or fry them; the whites will look thin and watery — spreading a lot in the pan — and the yolk will be flat and more likely to break. This doesn’t indicate that the egg is rotten, just that it isn’t at its peak. Pro tip: Crack eggs into a separate bowl before adding them to a dish if you’re uncertain of age or freshness.5 Things You Didn’t Know You Could Do With Your Microwave
How does the egg smell?
For detecting rotten eggs, use your nose. The smell is a result of a hydrogen sulfide gas built up inside eggs as it ages and breaks down, and is a dead giveaway that it has gone bad. Any eggs that produce this smell should be thrown out immediately.
Do the egg float test
To identify a rotten or old egg before cracking it open, the easiest thing to do is the float test. Place the egg in a glass of water. Fresh eggs will sink to the bottom, while bad eggs will float. (And should be thrown out.) If the egg sinks but rests with the wider end facing up, it is older, but still OK to cook with and eat.
What makes a floating egg bad?
As eggs get older they naturally start to deteriorate, producing gas inside the egg. This gas can evaporate through the pores of the egg shell, making the egg lighter. When enough gas is lost, the egg will be lighter than the water, causing it to float. In eggs reaching their best-by date, the gas may not have evaporated yet, but the gas bubbles are still present inside, which is why they may be “bottoms-up” in the water.
How to store eggs properly
- Store eggs in the body of the refrigerator (not the door), to ensure they maintain a consistent cool temperature.
- Keep eggs in the carton to protect them from damage and prevent them from absorbing the odour of other foods in the fridge.
- Store hard-boiled eggs in a sealed container in the fridge for up to one week.
- Store leftover yolks or whites in a sealed container in the fridge for 2-4 days.
- Store prepared egg dishes (quiches, frittatas, scrambles) in the fridge for 3-4 days.
- Store egg whites in the freezer for up to up to 12 months.
- To freeze raw whole eggs and whites, beat together until just blended, and freeze in a tightly-sealed container. (The Chatelaine Kitchen doesn’t recommend freezing yolks because they become somewhat gelatinous and behave differently when cooked and baked.)
- Avoid freezing hard cooked whole eggs and whites, they become tough and watery when frozen.
Originally published March 2018. Updated January 2019.