Egg Float Test: Myths, Procedure, Chart, Hypothesis vs. Reality

You’ve probably heard of the egg float test as a home cook or poultry farmer. It’s a simple and quick method to determine whether an egg is still fresh. 

But is it accurate? How does it work? What are the factors that affect the result? This article will answer these questions to help you understand the egg float test and its results. 

Introduction to the Egg Float Test

The egg float test, also known as the floating test for eggs, is a popular method to determine the freshness of an egg

It involves placing an egg in a water bowl and observing whether it floats or sinks. The result is supposed to indicate the age of the egg – a fresh egg will sink to the bottom, while an old egg will float to the top.

This egg-floating test is famous because it’s easy to perform and requires no special equipment. However, many misconceptions about the egg floating test can lead to inaccurate results.

How Does the Egg Float Test Work?

The egg float test is based on the principle of buoyancy. An eggshell is porous, which means it allows air to pass through. 

When an egg is freshly laid, there is very little air inside the shell. However, as the egg ages, the air cell inside the shell grows larger, and the egg becomes less dense. 

This change in density affects the egg’s buoyancy in water. When you place an egg in water, the egg displaces some water, creating an upward force known as buoyancy. 

The buoyant force equals the weight of the water displaced by the egg. If the egg is denser than the water, it will sink. 

The less dense it is, the more it will float. A fresh egg has a smaller air cell, so it is denser and sinks. An old egg has a larger air cell, which is less dense and floats.

Egg Float Test Myth vs. Reality

Egg Float Test Myth vs. Reality
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The egg floating test is a simple and convenient way to check the freshness of an egg, but it’s not foolproof. There are several myths and misconceptions about this test that we need to clear up.

Myth #1: The Egg Float Test Determines Egg Safety

The egg float test only measures the age of an egg, not its safety. An old egg may float, but it doesn’t necessarily mean it’s bad. Similarly, a fresh egg may sink but still, be contaminated with bacteria. The only way to ensure egg safety is to cook and handle them properly.

Myth #2: The Egg Float Test Works for All Types of Eggs

The egg float test works well for chicken eggs but may need to be more accurate for other types of eggs, such as quail or duck eggs. These eggs have different densities and air cell sizes, so the results may be misleading.

Myth #3: The Egg Float Test Always Gives the Same Result

The egg float test is affected by several factors, such as egg age, temperature, and humidity. Even two eggs from the same carton may give different results. Therefore, it’s essential to use other methods to confirm the freshness of an egg.

Myth #4: The Egg Float Test Can Tell You the Age of the Egg.

The egg float test can only give you an indication of the freshness of the egg. It’s not a reliable way to determine the exact age of an egg.

Factors That Affect Egg Freshness

The egg float test result is not only determined by the age of the egg but also by many other factors. Here are some of them:

Egg Age

As mentioned earlier, the age of an egg affects its buoyancy in water. The older the egg, the larger the air cell, and the greater the likelihood that it will float.


Egg temperature also impacts the size of the air cell. If the eggs are stored at a warm temperature, the air cell will grow faster, causing the eggs to age more quickly.

Eggs should be stored at a consistent temperature of around 40 °F. Higher temperatures can cause the eggs to spoil faster.


Humidity can affect the porosity of the eggshell, which in turn affects the air cell size. Therefore, eggs stored in a humid environment will have a larger air cell and may float even if they are relatively fresh.

Egg Size

The size of the egg can also impact the egg float test result. More giant eggs have larger air cells, so they may float even if they are fresh.

Egg Handling

You should handle eggs carefully to avoid cracking or breaking the shell. Cracked eggs may allow bacteria to enter the egg, even if fresh.

Understanding the Egg Float or Sink Test Results

Now that we understand the science behind the egg float test, let’s look at how to interpret the results. You’ll observe one of two things when performing the egg floating test.

  • The egg sinks to the bottom and lies flat on its side: This indicates that the egg is fresh and safe to eat.
  • The egg floats to the surface: This indicates that the egg is no longer fresh and should be discarded.

Egg Float Test Chart and What It Means?

Here’s a handy chart that summarizes the egg float test results:

Egg PositionEgg Freshness
Sinks to the bottom and lies flat on its sideFresh
Sinks to the bottom but stands upright or tilts slightlyLess fresh but still good to eat
Floats to the surfaceNo longer fresh, it should be discarded
A table about egg float test chart results

The egg floating test chart shows the relationship between the egg position, air cell size, egg age, and freshness. Fresh eggs sink to the bottom of the water and have a small air cell. 

An egg that tilts up but doesn’t float is less fresh but safe to eat. An egg that floats to the top of the water surface is old and should be discarded.

Note: It’s important to note that even if the egg floats, it doesn’t necessarily mean it’s bad. You can still use the egg for cooking or baking, but it’s not recommended to eat it raw.

Egg Float Test Pictures and Examples

Here are some pictures and examples of the egg float test results:

Fresh Egg

A fresh egg will sink to the bottom and lie horizontally.
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A fresh egg will sink to the bottom and lie horizontally.

Less Fresh Egg

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A less fresh egg will tilt up but still touch the bottom of the bowl. This means the egg is two to three weeks old.

Old Egg

An old egg can float to the top and have a large air cell.
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An old egg can float to the top and have a large air cell. This means it is a two to three months old egg.

Egg Float Test Science Experiment with Its Hypothesis

If you want to perform a science experiment with the egg float test, here’s a hypothesis you can test:


If you’re someone who loves science experiments, then you’ll enjoy this one. You can perform the egg float test as a science experiment to test the hypothesis that the size of the air cell affects the egg’s buoyancy. Here’s how to do it:


  • Fresh eggs
  • Glass of water
  • Marker
  • Ruler


  1. Fill a glass with water
  2. Measure the depth of the water.
  3. Gently place an egg in the water.
  4. Measure the depth of the water again.
  5. Calculate the difference between the two measurements. This is the egg’s buoyancy.
  6. Repeat the experiment with eggs of different ages and compare the results.

Other Methods to Test Egg Freshness

While the egg floating test is a quick and easy way to check egg freshness, it’s not the only method. Here are some other methods you can use:


Hold an egg to a bright light source and look for signs of a developing embryo or blood spots. A fresh egg will have a small air cell and a clear yolk. 

Also read: Best egg candling lights

Sniff Test

Smell the egg by cracking it open and sniffing. A fresh egg will have almost no odor, while a rotten egg will have a strong, unpleasant smell. 

Plate Test

Place an egg on a plate and spin it. A fresh egg will spin quickly and smoothly, while an old egg will wobble or not spin at all. 

Visual Inspection

Look at the egg for any signs of cracks, discoloration, or other defects. This may indicate that the egg needs to be fresh.

Carton Date

Check the carton for the date the eggs were packed. Use the eggs within 3–5 weeks of the packing date for the best freshness.

FAQs on Egg Float Test

Is the Egg Float Test Accurate?

The egg float test is a reliable way to determine the freshness of an egg. However, it’s essential to keep in mind that even if an egg sinks, it’s still possible for it to be rotten. Always use your judgment and check for any signs of spoilage before consuming the egg.

Can You Eat a Pink Yolk Egg?

A pink yolk can be an indication of bacterial contamination or the presence of blood. It’s not recommended to eat an egg with a pink yolk. According to the USDA, Pink or pearly egg white (albumen) indicates spoilage due to Pseudomonas bacteria.

Can You Eat a Red Blood Spot Yolk Egg?

A red blood spot yolk is safe to eat and doesn’t indicate spoilage. You can remove the spot with a knife if you prefer.

Can You Eat a Black Color Inside Egg?

A black or green color inside the egg may indicate spoilage or bacterial contamination. It’s best to discard the egg.

What’s to Happen If You Wash Eggs?

Washing eggs may remove the protective coating on the shell, making it easier for bacteria to enter the egg. It’s recommended to store eggs unwashed and wash them just before using them.

What happens if You Eat an Old Egg?

Eating an old egg may cause food poisoning, as the egg may contain harmful bacteria. Therefore, it’s best to discard old eggs.

What Should You Do if You Accidentally Eat an Expired Egg?

If you accidentally eat an expired egg, monitor your symptoms and seek medical attention if you experience any signs of food poisoning.

How Long Do Egg Whites Last?

The egg whites can be kept in the refrigerator for up to 4 days.

Conclusion: Should You Rely on the Egg Float Test?

The egg floating test helps check egg freshness, but it’s not foolproof. Use other methods to confirm the result and ensure egg safety. 

Remember to handle eggs carefully and cook them thoroughly to avoid foodborne illness. Always use your judgment and check for any signs of spoilage before consuming the egg. 

With the information in this article, you should be able to confidently use the egg float test to ensure that your eggs are fresh and safe to eat.

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Hi, I'm Bijaya Kumar, and I've been raising chickens for the last 12 years. For the past 30 years, backyard poultry farming has been a family business for us. We raise chickens of different breeds in the backyard.

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