Science Fact - Eggcraft

Have you ever had a carton of eggs in your fridge for too long? You know it's a long time because you can't remember ever buying them, and so you have no idea if they're any good. The gut-wrenching odour of rotten eggs can turn you off of these tasty ova for quite some time, so is it worth the risk to open one up and find out what lays inside? How long does it take for eggs to actually go bad, anyway? Should bad eggs be a real concern if the carton has been sitting in the back of your fridge for a few weeks? Or more likely, a few months?

Eggs can go bad at room temperature within a week. But unless you live on a farm or have a constant supply of fresh eggs, you'll probably keep your eggs in the fridge. In that case, eggs can last several weeks. However, as time goes by the eggs lose their deliciousness and will be less pleasing to eat, even if they're not considered to be 'bad'. These eggs can still be used to bake with, but there is a good chance that if you have really old eggs you don't bake very often. So how can we tell if an egg has gone bad without risking the release of that characteristic putrid smell?

Luckily for us, there is an easy test you can do to find out if your eggs are suitable for either eating or chucking at passing strangers. You simply put the egg in water and see what happens. Follow the guidelines made up for the witch trials: throw them in water. If they float, they're bad and should be destroyed. If they sink, they were never bad to begin with. And again, luckily for us, good eggs can hold their breath underwater for a very long time so we don't need to worry about killing the innocent eggs.

To do the test, you fill up a mug or measuring cup with water and place the egg inside. If it sinks to the bottom and lays on its side, it's still great. If it stands up on the bottom, it's becoming more stale but is still edible. If it floats, then you should toss them somewhere other than the frying pan.

Why does this happen? Eggs have tiny pores in its shell that can let moisture out and air in. When an egg is laid, it contains a small air pocket and a lot of eggy goo (water, proteins, cholesterol, etc). Fresh eggs with small air pockets will sink when placed in water. As the egg matures, it loses more water while the air pocket gets bigger. When enough air gets inside, the egg will float. This doesn't mean that all floating eggs are bad. It simply means that they are all old, and there is a bigger chance that they have spoiled.

So the next time you have old eggs in your fridge, test them out before you use them. If not, you might end up using them to make banana bread and serving it to your guests before finding out that the rest of the eggs float. Hypothetically speaking, of course. Don't you agree, Marisa?