d. You can develop good judgment in determining albumen and yolk condition
by breaking out an egg occasionally and checking your estimate of the candled quality
with the broken-out appearance.
3-13. AIR CELL
The air cell is one of several interior quality factors that you must consider.
a. The temperature of the egg within the hen is approximately 105oF (41oC). In
cooling to the ambient temperature after it is laid, the liquids contract more than the
shell and the inner shell membrane separates from the outer shell membrane, forming
the air cell. The air cell is usually formed in the blunt end of the egg because of its
porosity and the loose attachment of the inner shell membrane. If it is formed in some
other part, it does not cause the egg to be downgraded.
b. Further increase in the size of the air cell beyond that resulting from
contraction is due to evaporation of water from the egg. The rapidity with which this
takes place is caused by many factors, such as age, shell texture, temperature, and
humidity. The air cell is normally at the large end of the egg and is one of the first
factors observed in candling.
c. The air cell is perhaps the one quality factor that is easiest to evaluate as it
can be judged objectively by a simple measuring device--the air-cell gauge. In candling,
the air cell is considered by many as a relatively unimportant quality for determining the
broken-out quality of an egg.
d. However, the air cell is one of the factors of the US standards. Therefore, it
can be the determining factor in classifying the individual egg as to quality. Depth is the
only quality factor considered that pertains to the air cell. Movement is not considered a
quality factor, and the air cell may show unlimited movement and be free or bubbly.
e. The depth of the air cell is the distance from its top to its bottom when the egg
is held with the air cell upward. The following terms are descriptive of the air cell:
(1) Free air cell. An air cell that moves freely toward the uppermost part in
the egg as the egg is rotated slowly.
(2) Bubbly air cell. A ruptured air cell resulting in one or more small
separate air bubbles, which usually float beneath the main air cell. Bubbles often
accompany checks, so eggs with bubbly air cells should be observed closely when
determining the grade.