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How to test eggs for Freshness, Fertility and Meat/Blood Spots

Have you ever pulled an egg out of the fridge and wondered how fresh is it? What’s inside? Is it fertilized? How can I tell if it’s okay to use? We certainly have, so we’re here to share several ways to test eggs for freshness, fertility, and surprises.

Let’s take a look at some of these tests, then you can get on to trying them at home!

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A cracked open egg

How to Test an Egg for Freshness

Chicken egg shells are naturally good at protecting the egg inside, but they’re also porous, which means that over time, air seeps through the shell, making it lighter.

This air also makes eggs easier to peel, so it’s best to use older eggs if you plan to hard boil them!

The air inside of an egg can also help you to find out how old the egg is. Use the following methods to get an idea of egg freshness!

Water Method

Fill a bowl with cold water and gently place your egg in the water.

If the egg sinks to the bottom and lands on its side, it is VERY fresh and ready to use for cooking or baking, but not best for hard cooking. This egg has very little air inside, which means it hasn’t been sitting around for very long!

If the egg sinks to the bottom but one end tips up a bit, then the egg is a bit older and PERFECT for hard boiling.

If the egg floats at the top of the bowl, it’s likely very old and should be thrown away.

Candling Method

Candling eggs is another great way to test them for freshness and get a look as to what’s inside.

Candling an egg is when you hold it up to a very bright light in a dark room so you can see through the egg to the inside. This is typically done when you’re incubating eggs, but you can also do it to see how fresh the egg is.

There are many different ways to candle an egg, if you want some tips don’t miss our article: Candling Chicken Eggs Day by Day.

When you candle the egg you’re looking for the air pocket at the end. A fresh egg will have very little air space and a slightly visible yolk. A somewhat older egg will have a larger air space and a darker yolk.  

If an egg is near spoilage, it will have a very dark yolk and some spots throughout the white of the egg. In a spoiled egg the yolk can be misshapen and blended with the white of the egg.

Cracking it Open

Ultimately if you want to test for freshness you can do so by cracking open the egg. It’s a good idea to use a separate bowl from your baking or cooking ingredients to crack these eggs into, that way if there is a bad one, it doesn’t ruin everything else!

Don’t be concerned if the egg white is a milky color because that shows that the egg is very fresh. The older the egg, the clearer the egg white.

If you crack open your egg and get that classic rotten egg smell, you have your answer. Fresh eggs don’t smell bad and don’t look funny.

Two eggs, one cracked open, with a whisk and a feather on a black background

How to Test an Egg for Fertility

Candling Eggs to Test for Fertility

Candling is the best way to “see” into the egg. Using either a high powered flashlight or an Ovascope, you can check for blood vessels within the interior of the egg.

If you see a yolk with no red blood vessels in it that is a Yolker, unfortunately, it needs to be pulled from the incubator.

Another sign of an egg that is not a chick is a Quitter. You will observe a thin ring of blood around the yolk, and it too should be pulled from the incubator.

However, if you detect a group of blood vessels, what looks like an eye or even an outline or shadow of the chick’s body then you have a Winner and soon will have a fluffy little chick if all goes well.

Many of us have a hard time waiting to see if eggs in the incubator or under a broody hen are fertile or not. Here’s how you can run a couple of simple tests to see if there is indeed a chick inside.

Cracking it Open

You might decide to crack open an egg to see if it’s fertile or not. We do this when we’re planning to hatch eggs and want to check for viability before placing them in the incubator.

So how can you tell if a cracked open egg is fertilized?

If the yolk is still intact, you will find a white bullseye on your egg yolk which is actually two rings of white, one inside the other. This can be very small and hard to see, so it’s best to try to compare fertilized and unfertilized eggs to see if you can spot a difference in the white spot.

Fertilized eggs are perfectly safe to eat, and unless placed in a warm area, like an incubator or under a broody hen, they will not develop into a chick.

Testing Eggs for Meat and Blood Spots

You may be asking why are there meat or blood spots in my egg? What even is a meat spot and a blood spot?

A meat spot is a small bit of tissue inside the egg, usually attached to the yolk. Many people mistake this for an embryo, which it is not.

A blood spot is exactly what it sounds like, a small spot of blood inside the egg, also usually on the yolk.

These spots form when the hen has had a defect in egg production due to stress, nutrition, or just a plain abnormality in her anatomy. They’re a sort of ‘hiccup’ in egg production, and while not common, you will find them sometimes in farm fresh eggs.

You can most certainly eat an egg with a meat or blood spot or simply remove it with the tip of a knife. Either way, the egg is still edible.

Candling Eggs to Check for Meat and Blood Spots

Candling your eggs is the one way to detect a blood spot in your egg. A bright light and a darkened room will aid in being able to identify the abnormality.

Eggs that you buy at the supermarket usually go through the candling process before you buy them. They have high powered lights and machines to test for these abnormalities and all eggs with spots in them have been removed from the carton.

Candle the egg the same as you would to check for freshness or fertility, but this time you’re looking for spots. Look at every angle of the egg and search for small dark spots around the yolk. These spots are easiest to see in white eggs and can be near impossible to see in darker brown eggs.

Which brings us to the next option…

Cracking It Open

If candling doesn’t work, the only other option is to crack the egg open and look for meat or blood spots. They’re pretty obvious when you do find them, and can be removed with a spoon, knife, or by scooping them out with the shell of the egg.

If you’re too scared to eat an egg that had a blood spot or a meat spot (many people are) don’t worry, but don’t throw it out!

You can mix eggs into your dog’s food for an extra bit of nutrients, they don’t mind the spots at all. Or you can feed the egg back to your chickens. There’s no harm in it at all!

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