How to Test Eggs for Freshness

Updated 08/06/19

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We’ve all done it. You're standing in front of the open refrigerator door, carton of eggs in hand, staring hard at the jumble of numbers and dates printed on the side before popping the top to inspect the eggs, all the while wondering if they’re expired (you can't remember buying them), and what would happen if they were and you ate them—would it be totally fine, would you get sick… or worse?

Here’s how to decipher the dates on the carton and, if necessary, put your eggs through an effortless test to double check whether they’re fresh enough to eat or if they're literally bad eggs that should be thrown out.

Deciphering the Dates on an Egg Carton

Unfortunately, it’s not the most straightforward thing to determine when eggs are actually expected to expire—labels on cartons can be tricky and will take a little effort to decode. 

According to U.S. Department of Agriculture guidelines, “Each carton of USDA graded eggs must show the date of packaging, the processing plant number, and may include an expiration date. To determine freshness, a Julian date or pack-date calendar can be used. This three-digit code indicates the date of packaging, starting with January 1 as 001 and ending with December 31 as 365. You can store fresh shell eggs in their cartons in the refrigerator for four to five weeks beyond this date.”

So how can you take that information and make it work for you? Just keep these three things in mind:

  1. Always check the sell-by or (if there is one) expiration date on the carton before purchasing eggs and don’t buy eggs that are past either date.
  2. Instead of storing eggs on the door of your fridge, store them in the carton you purchased them in on a shelf in the main body of the fridge—it’s colder there and will help keep your eggs fresher, longer.
  3. Try to use the eggs no more than five weeks after the Julian or pack-date printed on the carton. If you have any eggs past this date, test them for freshness.

Testing the Freshness of Eggs With the Float Test

All you need in order to test your eggs for freshness is a bowl (or pot, or bucket, what have you!) full of cold water. Take the eggs in question and gently put them into the water.

Eggshells are porous and only get more porous over time, allowing air to pass through the thin, permeable shell straight into the egg. The older the egg is, the more air gets into the egg (typically in the air sac or cell, the pocket of air between the shell and the membrane surrounding the egg), and the more buoyant it becomes.

So, if your eggs float—they’re bad, and unfortunately, need to be tossed out. If they sink—they’re fresh as can be and can be used for anything. If they hover somewhere in between—they’re still good to eat, but aren’t very fresh, so use these eggs as soon as possible, reserving them for hard boiling or baking, as they’re not ideal for any raw or runny yolk situations.

Testing the Freshness of an Already Cracked Egg

If you already cracked your egg and are concerned about the freshness—don’t worry! There’s a simple way to test cracked eggs for freshness, too. Wherever your egg was cracked, transfer it gently (without breaking the yolk) to a plate so you can inspect the egg from side.

Get eye level with the egg to check it out—the yolk should be well rounded on top (not flat) and the white should be visible as a thick layer that “sits up” from the plate. If the yolk is flat on top and the white is very watery, low, and spread out, the egg is no longer fresh.

If you ever crack an egg and it smells off or rotten in any way, throw that egg out! Even it passed the float test, there’s something wrong here, and honestly, it’s not worth trying to salvage, promise.

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