Is an egg fresh? Many people put a lot of stock in the date that is printed on the packaging to tell them when the food has gone bad, but sell-by dates are frequently somewhat arbitrary and are not the same thing as expiration dates. If you have been discarding eggs solely on the basis of the dates printed on the carton, you may be throwing away perfectly edible food.
Eggs can frequently be consumed even well after the date that is printed on the packaging instructs you to dispose of them. The following are a few different ways that you can test them to determine how fresh they are before you find out the hard way how fresh they really are.
Your eyes and nose are the best tools for determining the freshness of meats, produce, and herbs. When something is moldy or smelly, it is fairly obvious to the naked eye and nose. The problem is that you can’t taste or smell an egg before you crack it (unless you have a lot of experience), so how can you tell if it’s still edible?
Is an egg fresh? Try the candling method
The first test, which is known as candling and is typically performed on eggs before they are sold, can also be done at home. This test determines whether or not the eggs are fit for consumption. A piece of cardboard with a hole that is slightly smaller than an egg is placed between the observer’s eye and a light source, and the egg is then held in front of the light source in the manner depicted in figure 4.
This technique is used to determine whether or not eggs have been recently laid. The condition of the egg, the size of its air space, and whether or not mold has grown on the egg or it has been spoiled by any method that is considered to be “normal” are all revealed by the rays of light that penetrate the egg and pass through it.
Figure 5 depicts the appearance of an egg when it is candled at various stages of its freshness. When an egg is fresh, it will have the appearance shown in (a), which means that the yolk will be difficult to differentiate from the white of the egg, with the exception of a slightly darker area located in the middle of the egg, and the egg as a whole will appear transparent, bright, and spotless.
Candling an egg will reveal a slightly darker yolk, a cloudier white, and a larger air space in an egg that is a little bit older, as shown in example (b). As seen in view (c), various spots and blotches of a darker color tend to develop on the surface of an egg that has become waterlogged or that has begun to deteriorate.
If an egg has gone bad, the contents of the shell will have a dark appearance in candling, and the yolk will have the appearance of being mixed in with the white, as in (d).
Floating egg method
If nothing has been done to preserve the eggs, the straightforward method for determining whether or not they are fresh, which is depicted in Figure 3 and consists of placing the eggs in a glass that is filled with water, will be found to be accurate.
If the egg is three weeks old, the broad end will rise slightly from the bottom of the glass, in contrast, an egg that has just been laid will immediately sink when the water is added to the container containing it. When placed in water, an egg that is three months old will sink until only a small portion of the shell is exposed.
In contrast, an egg that is either older than three months or stale will float to the surface of the water and remain there until nearly half of it is visible.
An additional method for determining whether or not an egg is fresh is to crack it open in a saucer and then carefully examine the contents of the shell. If the egg was recently laid, there will be no discernible odor, and the white will be transparent, elastic, and relatively thick.
Additionally, the area where the white meets the yolk will be nearly solid. The yolk of such an egg will have a uniform yellow color, free of lighter or darker spots, and will be able to clearly differentiate itself from the surface of the white, as depicted in Figure 6(a).
A perfectly fresh egg may occasionally have a tiny spot of blood on the yolk, but even though this is unpleasant to look at, it does not impact the quality of the egg in any way. The yolk of an egg that has not been kept in the refrigerator for an extended period of time will spread out when the egg is cracked into a saucer (b).
When an egg has been sitting around for quite some time, the membrane that normally surrounds the yolk can easily become damaged. As a result, even when such an egg is broken carefully, it is likely that the yolk and the white will run together.
Here’s a great video addressing the question is an egg fresh: