Myth: Bad eggs will float / good eggs will sink - Page 5
A lot of the confusion over bad eggs that do not float seems to be caused by eggs left outdoors in an uncontrolled environment. I believe that the float test is highly reliable if all your eggs have been stored in doors, and especially so if refrigerated. While fresh eggs can be left on the countertop for over a month and still be edible, I believe they can be good for three times as long refrigerated.
I've had chickens for a number of years now, and presently have 6. 2 of them are marans, at least one of these lays the occasional good egg that float. Some of the don't just float, they bob high in the water like bouys. These eggs are no more than a few days old, and are perfectly edible. The shell is a slightly different texture and a slightly lighter shade than their normal eggs. You can feel that it's going to be a floater. The white is very thick and gloopy.
Float test is a myth.
My eggs are rarely last more than two or three weeks in my house and I was concerned when so many seemed to float. After hearing lots of confusing misinformation -- I found this from the USDA to should put everyone at ease.
What does it mean when an egg floats in water?
An egg can float in water when its air cell has enlarged sufficiently to keep it buoyant. This means the egg is old, but it may be perfectly safe to use. Crack the egg into a bowl and examine it for an off-odor or unusual appearance before deciding to use or discard it. A spoiled egg will have an unpleasant odor when you break open the shell, either when raw or cooked.
Bottom line: Your nose knows. Crack all eggs into a small bowl and examine and sniff before it goes into the mixer or pan.