How to Tell If an Egg Is Bad

Have you ever been right in the middle of preparing a recipe, only to realize the carton in your fridge passed its expiration date days ago? Or maybe you picked up farm-fresh eggs without any date stamp at all and forgot when you bought them.

Fortunately, checking whether an egg is still safe to eat is remarkably easy. Here is your practical guide to testing egg freshness and identifying true spoilage before you start cooking.

Method 1: The Freshness Tests

1. The Cold Water Float Test

Fill a deep bowl or wide glass with cold water and gently lower your egg inside.

Every egg contains a small interior air pocket. Over time, moisture evaporates through the microscopic pores in the shell, allowing more air inside. As that air pocket expands, the egg becomes increasingly buoyant.

• If the egg sinks to the bottom and lies flat on its side: It is at peak freshness.
• If it stands upright on the bottom: It is losing moisture and getting older, but it is still perfectly safe to cook and eat. (In fact, eggs like this make the easiest hard-boiled eggs to peel!)
• If the egg floats to the top: It is quite old. Floating does not automatically mean the egg is rotten, but it is definitely past its prime. Crack it into a separate bowl and perform the sniff test before using it.

2. The Shake Test

Hold the raw egg up to your ear and give it a gentle shake.

As an egg ages and loses moisture, the yolk and white shrink while the air cell expands. That extra empty space gives the contents room to slosh around inside the shell.

• A very fresh egg will produce little to no sound at all.
• A distinct sloshing sound tells you the egg is older. It might still be edible, but you should inspect it closely once cracked.

3. The Plate Inspection

Crack the egg onto a flat plate to observe how the yolk and albumen (the white) behave.

Fresh eggs have a firm, bouncy internal structure. As they age, the proteins break down and thin out.

• Check the yolk: A fresh yolk sits high and rounded like a dome. If the yolk looks flat and breaks at the slightest touch, the egg is older.
• Check the white spread: A fresh egg white stays relatively compact with a thick inner ring around the yolk. If the white is watery and runs freely across the entire plate, freshness is gone.
• Check the white clarity: A cloudy or milky white actually indicates extreme freshness (caused by naturally dissolved carbon dioxide). A clear, translucent white means the egg is older, though still fine to eat.

Method 2: Spotting Spoiled Eggs

Freshness and spoilage are two different things. An egg can be older yet still safe, but a spoiled egg is dangerous and must be discarded immediately.

1. The Sniff Test

The human nose remains the most reliable tool in your kitchen. Spoiled eggs give off a unmistakable, pungent sulfur stench.

• You will notice this sulfuric odor instantly once the shell cracks (and sometimes even through the shell before opening).
• If an egg smells off—whether raw or cooked—throw it out immediately. Never taste-test a suspicious egg.

2. Look for Unusual Discoloration

Crack the egg into an empty ramekin before adding it to your pan or mixing bowl, then inspect the colors carefully.

• Yolk color variations: A rich golden-orange yolk compared to a pale yellow one only reflects the hen’s diet (such as corn, alfalfa, or marigold petals). It has nothing to do with freshness or safety.
• Bacterial warning signs: If the white appears pinkish, pearlescent, iridescent, or greenish, the egg is contaminated with Pseudomonas bacteria. Toss it immediately.
• Green rings on hard-boiled yolks: If a hard-boiled egg has a dull grayish-green perimeter around the yolk, do not worry. This is simply a harmless chemical reaction between sulfur and iron caused by overcooking or water high in minerals.
• Blood spots: Finding a small red or brownish speck on the yolk does not mean the egg is fertilized or rotten. It is simply a ruptured capillary from when the egg was formed. It is entirely safe to eat, or you can gently lift it out with the tip of a spoon.

A Quick Note on High-Risk Kitchens

While older eggs that pass the sniff test are fine for everyday baking or scrambles, individuals with vulnerable immune systems—including infants, pregnant women, and the elderly—should always use the freshest eggs available, cooked thoroughly until both the whites and yolks are fully set.