How Can You Tell If An Egg Is Fresh?

With free-ranged chickens, it’s not uncommon to find a clutch of eggs laid somewhere other than the chicken’s laying box.  It’s bound to happen sooner or later, and will probably happen often.  The other day, we went to retrieve something from the gardening shed and found a clutch of eggs.  We had no idea how old they were, so we do what we always do instead of just throwing them out; we floated them.  These eggs were of varying freshness, so I snapped a couple of pics of how floating is done.

Fill a glass or a measuring cup with water that is deeper than the egg is long.  Gently drop the found egg in the water to see if it floats or sinks.  If the egg sinks and lays directly on the bottom, it is very fresh.

If the egg has one end that sinks and the other end that floats a little, then it’s still perfectly fine to eat, but has a little age on it.  It’s probably the perfect age for a boiled egg because the shell will peel easily.  The one in the picture below does indeed have one end sitting on the bottom, but it looks a little skewed because of the angle of my photo.

An egg that is even older than the one that sits sideways will float completely straight up and down, but still touches the bottom.  These are probably still alright to eat, but we usually make this the cut-off between edible and too old.

If the eggs floats, it’s what we call P.I. or “past it”.  Toss this one out!  It was likely laid at least a couple of months ago.

The reason that old eggs float and fresh eggs don’t is because of the air pocket that is naturally present in the large end of all eggs.  As the egg ages, moisture leaves the egg through the pores of the shell and the air pocket becomes larger, causing the egg to float.  Below are pictures of air pockets at various stages.

The air pocket is also the reason that really fresh eggs don’t peel as easily as older eggs when they’re boiled.  Next time you make boiled eggs, take a look at the difference in the air pockets between ones where the shell comes right off and ones that you really have to work at.  You’ll be able to see it in the size of the flat part on the boiled egg because it was once the air pocket!  Don’t you just love the wonders of nature?!