A. First, that’s great you are getting farm-fresh eggs. Knowing how to test for freshness is a good bit of information to have — whether you’re going to use eggs that are store bought or from a friend.
I remembered something about dropping a raw egg in water to see if it was fresh, but wasn’t sure if the fresh eggs sank — or floated. So, I looked it up.
Here’s what About.com tells us:
You can get an approximation of an egg’s age by this method:
Gently drop the egg into the bowl of water. If it:
- 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.
For a test just to see if the eggs are all right to use, dissolve 2 tablespoons salt in 2 cups cold water, then put the egg in the water. If it sinks, it’s good; if it floats, it’s too old.
Eggs act this way in water because of the air sac present in all eggs. As the egg ages, the air sac gets larger because the egg shell is a semi-permeable membrane. The air sac, when large enough, makes the egg float. Eggs are generally good for about three weeks after you buy them.
And how do you see if an egg is hard cooked? Spin it on a flat surface. If the egg wobbles, it’s fresh because the insides are moving around. If the egg spins smoothly, it’s cooked.
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