Did you know that many of the eggs that you purchase by the dozen in your local grocery store are already weeks old before they hit the shelf? It may seem odd to us in the U.S., but in most countries you don’t get your eggs from the refrigerated section of the store, they are instead on a shelf right next to the bread.
An egg freshly hatched from the hen will last for several weeks without refrigeration due to a special coating that is on the outer shell. Most eggs that we get from the stores keep this coating, called “bloom,” until they are ready to be packaged.
This bloom is removed for sanitary reasons as it can hold some fairly nasty bacteria, but the major downside is that it cuts the shelf life of that egg into a fraction of what it could be.
So how does this bloom help to keep the egg fresh?
The bloom acts as an oxygen inhibitor and keeps it from breathing. The slower the egg breathes the longer its shelf life.
So if you are able to get farm fresh, unwashed eggs, you should be able to store them outside the refrigerator for several days without reducing the quality of the eggs. Even your store bought eggs may be safe well past their expiration dates.
There is even a simple test that will tell you just how fresh an egg is and all you need is a bowl of water.
When you get ready to use your eggs, fill a bowl of water with two teaspoons of salt and gently place the egg into the water.
If the egg:
-Sinks to the bottom and stays there, it is about three to six days old.
-Sinks, but floats at an angle, it’s more than a week old.
-Sinks, but then stands on end, it’s about two weeks old.
-Floats, it’s too old and should be discarded
Eggs react this way in water because of the air sac present in all eggs. The shell of an egg is a semi permeable membrane that allows oxygen to enter the shell but not leave it. As the egg ages this air sac begins to increase in size. The larger the air sack the more buoyant the egg.