test for freshness of eggs

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

How to Test for Freshness of Eggs?


We dislike to be the ones to break it to you, however the eggs you simply purchased in the supermarket are most likely not as fresh as you may believe they are.

Think of it: they needed to be laid, processed, delivered and stocked. This is absolutely made with a fantastic amount of speed, however still: not as fresh as you believe.

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We have all most likely had this experience: The container of eggs in your refrigerator have been there for a while, and the date marked on the side is simply a date– does that mean when they should be offered by or by when they should be consumed?

And, considering we do not understand when the eggs were delivered and for how long they were kept prior to landing on the shop rack, it doubts how fresh they actually are.

Eggs are typically great for about 3 weeks after you purchase them, however if you do not keep in mind when you bought the container, that details isn’t much of help.

A great deal of people depend on the date on the packaging to tell them when food has actually gone bad, even with eggs, however the sell-by dates are typically somewhat arbitrary and are not expiration dates.

If you have actually been tossing your eggs based upon the dates on your container– you could be squandering completely excellent food.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

Did you know that your typical store-bought egg is 3 weeks old however they might extremely well be months old.

Farmers can keep eggs for 30 to 90 days before they are shipped off for “packaging” (the information that I discovered for that number varied a lot, so it’s a large range).

Eggs are numerous more weeks old by they time they are packed, shipped, and then acquired by you. Shocked? I sure was.

This details was a huge incentive for me to stop buying commercial eggs. When production from my own hens is down I look for a regional source for eggs.

Not just is the egg quality and freshness exceptional, but I’m likewise supporting the local economy (and when you are a small business owner that’s something tied extremely closely to your heart).

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

It’s hard to tell how old an egg is when you buy it, whether you purchased commercial or in your area raised eggs. The very first hint is the yolk.

An old yolk sinks down flat and thin but a brand-new yolk stands up extremely high and round, it looks more like an orange ball in the middle of the white.

When my hens free variety a lot in the summertime they tend to discover their own secret places to nest in the lawn and sometimes those concealed nests are almost impossible to discover.

When I or the kids do discover a secret clutch I’m in no hurry to split an egg open to see how perky it’s yolk is however. Have you ever been subjected to the smell of a truly rotten egg? Not an enjoyable experience.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

Eggs are often still good to eat long after the date on the product packaging says to toss them out. If you want to test how fresh they are prior to learning the hard way, here are a few approaches for evaluating them.

Your eyes and nose are the very best tools for identifying freshness with meats, produce and herbs– it’s quite obvious when something’s musty or smelly.

But you can’t smell and see an egg prior to you break it (unless you’re highly knowledgeable), so how do you tell if it’s still great?

different poultry egg colors
different poultry egg colors

However do not throw out those eggs right now! Fortunately, there are 3 simple methods to test for freshness of eggs and identify if they are still safe to consume.

Test for Freshness of eggs
Float Egg Freshness Test

1.  The Egg Float Test: Does it Float or Sink in a Bowl of Water?

The egg float test has been performed for as long as most people can recall. It’s a tried-and-tested way for determining whether eggs are fresh or not, but is it as efficient as we believe? Let’s investigate by examining how this test works.

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So how fresh are the eggs? There’s a genuine easy test you can do to know. Simply put an egg in a glass of water. If it’s fresh, it’ll sink. If it’s old, it’ll drift.

The egg float test is commonly used to determine the freshness of an egg. The results indicate the approximate age of an egg, and it only takes around five to ten minutes to complete a carton of eggs.

However what about if it’s someplace in the middle? We discovered a chart that’ll assist you figure out simply how fresh (or not so fresh) your eggs truly are. Examine it out and after that make your choice on what to do with it.

test freshness of eggs in a bowl of water

How to Perform an Egg Float Test?

To perform an egg float test, you’ll need a bowl or cup large enough to hold an egg. Fill the container with water to a depth of at least two inches. Cold water is the most effective.

Before you begin, inspect all of your eggs for cracks, as they could affect the outcome. Then, one at a time, put an egg into the water and observe what happens.

Here are some examples of probable outcomes of the Egg Float Test:

  • The egg remains on its side at the bottom — it is quite fresh.
  • The egg remains on its side at the bottom, but one end is slightly elevated – it is still fresh.
  • The egg is touching the bottom but standing upright – it is relatively fresh and safe to eat.
  • The egg rises to the surface — it’s very old or rotting, and it’s not safe to eat.

Like an enjoyable science experiment you might have carried out in school, this test for freshness of eggs is not just easy likewise can inform you the approximate age of the egg.

All you need is the egg and a bowl of cold water. Ensure there’s adequate water in the bowl to totally cover the egg, then carefully drop the egg into the bowl of water.

Your egg can do among 4 things and each will identify its freshness. If it sinks to the bottom, rests on its side, and remains there, it is extremely fresh.

If the egg sinks however drifts at an angle or stands on end, the egg is a bit older (a week to 2 weeks old) however still alright to consume. If the egg floats, it’s too old and need to be disposed of.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

The science behind this is that as eggs age, the shell ends up being more permeable enabling air to stream through.

The more air going into through the shell, the bigger the air cell ends up being (the pocket of air in between the membrane and shell in the bigger end of the egg). The air sac, when big enough, makes the egg float.

Why the Float Test for Freshness of Eggs Works So Well

The reason this approach works is that the eggshells are porous, which indicates they allow some air to get through. Fresh eggs have less air in them, so they sink to the bottom.

However older eggs have actually had more time for the air to permeate the shells, so they’re more resilient and will drift.

If you are trying to find more of a cut and dry test, liquify 2 tablespoons of salt in 2 cups of cold water. Put the egg in the water– if it sinks, it’s great; if it floats, it’s too old.

Is the Egg Float Test a Reliable Test for Freshness of Eggs?

The egg float test is not a myth, despite its age and simplicity. To this day, it remains one of the most accurate egg testing methods. If the egg floats, it is spoiled and should not be consumed.

Those who are well-versed in this procedure may be able to determine the exact age of each egg. Floating a fertilized egg in water, however, does not reveal its sex, contrary to popular belief.

2.  Examinine the Egg White

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

You will require to break the egg for this test for freshness of  eggs, however if you intend on preparing the egg (besides tough boiling) or contributing to a baked excellent dish, you would be opening it up anyhow.

Break the egg onto a plate or other flat surface area and look carefully at the consistency of the egg white– you desire it to be somewhat nontransparent, not expanded excessively, and appear thick and rather sticky.

If it is watery, clear, and runny, the egg has actually lost its freshness. This is because of the truth that as eggs age, the white turns liquidy and breaks down. You will likewise observe the yolk will be somewhat flat on the top rather than rounded.

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3.  The Flashlight or Candling Test for Freshness of Eggs

Some individuals likewise declare you can hold an egg approximately your ear and shake it to evaluate for freshness. If you can hear liquid sloshing sound inside the egg, it’s most likely spoiled, however if you hear absolutely nothing, it’s great to consume.

Personally, though, I don’t think this method is as reliable.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)


Additionally, there is the candling approach on testing of eggs freshness, which is used mostly for screening egg quality before they’re sold, but it could help identify freshness too, though it’s harder to see at later phases.

Candling is not a simple procedure, but it is effective. In a dark room, shine a bright light on the egg. People used to use candles for this, but there are many safer alternatives now. A flashlight is usually the best option.

To use this procedure, hold the big end of the egg up to the light. Turn the egg quickly from left to right, and the contents inside should light up.

This procedure will show you the size of the air cells in the egg. The freshest eggs will have an air cell that is less than 1/8 inch thick. As the egg ages, the air pockets expand due to gasses replacing the water lost during evaporation.

Candling normally takes some practice before you can make accurate judgments about the age of an egg.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

You can put a flashlight right beside the eggshell to light up the inside, however traditionally, a piece of cardboard with a little hole in it was utilized, with a source of light behind it and the egg in front.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

The above technique used to test for freshness of eggs will let you see the air area and mold, however it’s truly a challenging method to use.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

Above you can see a fresh egg (little air space, slightly noticeable yolk), a slightly old egg (bigger air space, slightly darker yolk), a nearly bad egg (actually dark yolk, spotty), and a spoiled egg (mixed in yolk, lots of dark), lit up using the candling technique.

If you want to see inside your eggs more frequently, try this LED egg candle light– it’s made to inspect if an egg is fertilized if you’re into that.

4.  The Smell Test for Freshness of Eggs

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

We have all experienced the odour of rotten eggs, however the smell generally has absolutely nothing to do with eggs at all. It is the sulfur that we acknowledge, which will release from an egg that has actually spoiled.

If the egg is truly past its prime, you might smell it through the shell; however if not and you’re worried about freshness, take a whiff after you break it.

If you don’t need the shell intact, you can likewise break the egg onto a plate or other flat surface to test how fresh it is. If it’s fresh, the yolk must be bright yellow or orange, and the white should not spread out much.

If you’re unsure, give it a good smell: fresh eggs should not have much of an odor at all.

Old or rotting eggs, as you might expect, have a far fouler odor than fresh eggs. Inedible eggs, whether raw or cooked, emit a distinct stench.

Try cracking the egg if you can’t tell just by holding it. You’ll definitely detect the odor of a broken rotten egg. If there are no odd odors, the egg is safe to consume.

It’s recommended to trash an egg if it smells strange. Then, carefully clean any surfaces that came into contact with the egg.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

The yolk will be flatter and the white will be much runnier in an older egg. An egg that spreads out when broken isn’t necessarily bad, though, simply older (and once again, helpful for hard-boiled eggs).

If it’s gone bad, you most likely will not even need to do the smell test– even a little rotten eggs will have a very strong, unique odor you’ll see right away.

To Use or to Toss Test for Freshness of Eggs

Undoubtedly, if your egg smells horrible, you need to throw it away. However if the egg is revealing indications of age but not set for the garbage, you can still use it.

Older eggs are perfect for tough boiling– given that the air cell is bigger, there is more area in between the shell and the egg, making it simpler to peel.

And if you believe a few of the eggs in your fridge are hardboiled however not exactly sure which, you can quickly figure out the two.

Take the egg and spin it on a flat surface area; if the egg wobbles, it’s fresh (the insides are moving). If the egg spins efficiently, it’s cooked well.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

Whether your eggs are fine to use or not, you will still be left with the shells and carton box. Do not toss in the garbage! Egg shells are excellent for the garden compost, in addition to cleaning teapots and making pathway chalk.

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And the cardboard containers are best for art tasks– use as a paint pallet, turn into a bird feeder, and utilize them as candle light molds. You can likewise conserve for your indoor or outside fires as they make excellent fire-starters.

5.  Perform a Plate Test for Freshness of Eggs

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

Another method that includes cracking an egg is the plate test. Crack the egg onto a plate and observe how it lies on the surface.

A particularly fresh egg will have a firm white section and a vivid yolk that sits prominently. Older eggs will have flat yolks that will soon spread across the platter.

A spreading yolk does not necessarily indicate that the egg is rotten, but it does indicate that it is not very fresh. In addition to the runny yolk, an egg that isn’t healthy to eat will have a bad odor.

6.  Examine the Egg Visually

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

Examining an egg’s characteristics might reveal a lot about it. Certain characteristics of the egg can indicate that it is no longer fresh.

Check to ensure that the egg shell isn’t greasy or powdery. Cracks are also a source of concern because bacteria can enter the egg. Mold could be present if the shell feels or looks odd.

Make sure there is no discoloration inside the egg when you crack it. If there is any pink, blue, green, or black in the yolk or white component, it means bacteria is forming.

7.  Examine the Carton Date

If you purchased your eggs at a store, the simplest option is to look at the expiration date on the carton. This date will be labeled “sell by” or “expiration date” depending on where you live.

Eggs that have passed their sell-by date aren’t always rotten. Eggs must be sold within 30 days of being packaged, but they may still be fresh enough to eat for a little longer. However, eggs that have beyond their expiration date will no longer be fresh.

Eggs that have not past their sell by or expiration dates are still fresh, but be aware of those that have. If you’re unsure whether the eggs are still safe to eat, you should do one of the above tests.

Why is it Dangerous to Eat Bad Eggs? The Importance of the Test for Freshness of Eggs

Since salmonella and other pathogenic germs exist in the majority of eggs, it is advised that you need to constantly prepare your eggs to well done.

The germs can be inside the shell, so even if you clean the egg or soft-cook it, you might get ill if it’s undercooked.

Always cook fried eggs to well done, cook rushed eggs till they are 100’C, and cook hard-cooked eggs up until they are entirely firm. And always refrigerate eggs, whether cooked or raw.

7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)

While it’s real that many eggs are not infected, if one is, you can get extremely ill. There have actually been massive break outs of salmonella from shell eggs in the past; in 2010, for instance, 60,000 Americans were sickened with salmonella from eggs.

If somebody in your house has actually a not strong immune system, is pregnant, or is young or senior, consider purchasing pasteurized eggs.

These are eggs that have actually been rapidly warmed to a temperature level high adequate to eliminate germs however low enough so the egg stays raw. Always follow expiration dates when you buy one.


  1. The Humane Society of the United States. “A Brief Guide to Egg Carton Labels and Their Relevance to Animal Welfare”. Hsus.org. Archived from the original on 18 May 2008. Retrieved 10 January 2010.
  2.  “Anatomy of an Egg”Science of Cooking. Exploratorium. Retrieved 30 October 2017.
  3.  How to Store Fresh Eggs Mother Earth News, November/December (1977)
  4.  “Candling eggs”University of Illinois Extension. 2019. Retrieved 6 June 2012Eggs are candled to determine the condition of the air cell, yolk, and white. Candling detects bloody whites, blood spots, or meat spots, and enables observation of germ development. Candling is done in a darkened room with the egg held before a light. The light penetrates the egg and makes it possible to observe the inside of the egg. Incubated eggs are candled to determine whether they are fertile and, if fertile, to check the growth and development of the embryo.”

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5 thoughts on “7 Proven Scientific Ways to Test For Freshness of Eggs (Updated January 2022)”

  1. Actually, i like old eggs because they most certainly peel easier when hard boiled. I have found that eggs refrigerated in the shell (no cracks of course) keep for a long, long time. It’s like the American obsession with keeping butter in the fridge all the time. Not necessary. can be at room temp for hours at a time. then back in the fridge with no harm done.

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