How to Tell a Fresh Egg From an Old One, Before and After Cracking It

An egg's shell gives little away about its age, and you cannot crack one open in the shop. In June 2026 Jagonews24 set out a few home checks: the carton date, the float test, the white and yolk once cracked, and the smell. Here they are checked against the advice of the US Department of Agriculture's Food Safety and Inspection Service (USDA FSIS) and the US Food and Drug Administration (FDA).

The carton date is not the day the egg was laid. FSIS says processors print "code dates" on cartons to rotate stock and control inventory. Under US rules an expiration date such as "Sell By" or "EXP" can be no more than 30 days from the day the eggs were packed, and a "Use by" or "Best before" date no more than 45 days including the packing day. Eggs bought loose from an open tray carry no date at all.

The FDA advises opening the carton to make sure the eggs are clean and the shells are not cracked. FSIS says never to buy cracked eggs or out-of-date eggs, because bacteria can enter through cracks in the shell. In the United States both agencies advise buying eggs only from a refrigerated case.

For the best-known home check, lower the egg gently into a deep bowl of water. A fresh egg stays on the bottom. As an egg ages, its broad end rises higher in the water, and a very old egg floats.

The reason is the air cell. FSIS explains that an egg is laid at 105 °F and normally has no air cell. As it cools, the shell and its contents contract at different rates, and an air cell forms, usually at the large end between the two shell membranes. Over time moisture and carbon dioxide escape from the white through the pores of the shell, air gets in and the cell grows, so the egg becomes lighter. Graders measure the same air cell by candling, holding the egg against a light: the smaller the air cell, the higher the grade.

A floating egg is not automatically a bad one. In FSIS's words, an egg that floats is old, "but it may be perfectly safe to use." The agency advises cracking it into a bowl and checking for an off-odour or unusual appearance before deciding to use or discard it. The float test tells you about age, not safety.

Over time, FSIS says, white and yolk lose quality as the yolk draws water from the white. An older egg spreads over a wider area when broken, its white is thinner and its yolk flatter and larger. A top-quality US Grade AA egg has a thick, firm white and a high, round yolk. The agency adds that a cloudy white is a sign the egg is very fresh, while a clear white shows it is ageing.

The clearest sign of a spoiled egg is the smell. FSIS says a spoiled egg has an unpleasant odour when the shell is broken, whether raw or cooked. Such an egg should not be eaten.

The FDA and FSIS advise refrigerating eggs promptly at 40 °F or below. Keep them in their original carton; FSIS says to place it in the coldest part of the refrigerator, not in the door. The FDA says to use eggs within 3 weeks for best quality, while the FSIS storage chart gives 3 to 5 weeks for raw eggs in the shell in the refrigerator. Eggs should not be frozen in their shells.

If eggs crack on the way home, FSIS advises breaking them into a clean container, covering it tightly, refrigerating it and using them within 2 days. Do not wash eggs first: FSIS says the wash water can be drawn into the egg through the pores in the shell and may raise the risk of contamination. Eggs sold in the United States are washed, which erodes the shell's natural coating, and that is why the USDA recommends refrigerating them to prevent the growth of Salmonella.

Photo: Piasoft / Wikimedia Commons (CC BY-SA 3.0)

Sources: Jagonews24, US Department of Agriculture Food Safety and Inspection Service (USDA FSIS), US Food and Drug Administration (FDA), Wikipedia