Take the egg in your hand and gently shake it. If it is fresh, you won't make much of shaking inside of the shell. If the egg is stale, then the inner content will be to actively move.
Use water to determine the quality of hen eggs. Type cool water in a pot or deep bowl, dip it in the eggs. Fresh will remain at the bottom in a horizontal position, those that lie in the refrigerator for a week, will lie in the water at an angle, and stale eggs will float to the surface vertically. This method is based on the fact that the longer lays the egg, the more air it's going. Accordingly, stale eggs pulls the surface air that has accumulated inside.
The freshness of eggs can be determined and externally. Tone fresh chicken eggs are smooth, the shell clean and a little shiny. Stale eggs matte, white becoming grayish or acquires a yellow tint.
Eggs can be checked with the purchase in the store. To do this, you should use the ovoscope is a special instrument for quality control with the help of their screening. Fresh egg whites are fully translucent, the yolk is in the center. Eggs that had lain a week or two, will be x-rayed, but the protein you will notice small dark areas. Spoiled eggs do not translucent.
Quality check can be arranged, smashing the egg on the plate. At the same time, pay attention to protein. From fresh chicken eggs it is lush, has a rounded shape, is tightly around the yolk, has two layers - jelly and liquid tight external. Older eggs lose the duality of the protein, breaking it, you get a liquid yolk and protein mass on the plate around.