The egg float test has been around for a very long time.
It is a useful and fast way to check if eggs are fresh and safe to eat.
The interesting thing is nobody really knows how it came to be and where this test came from.
Is this test accurate or just a myth?
In this article we will explain everything you need to know about the egg float test including how to perform the test, if it is accurate and much more…
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How To Do The Egg Float Test
The float test is a quick and simple way to check the freshness of an egg. It will take you about ten minutes to check a carton.
You will need a bowl that is large enough to put an egg in the bottom and be able to cover it with two inches of water.
Now before you start the egg float test you need to check your egg for cracks. There should be no cracks in the shell so discard any cracked eggs before testing.
Step 1: Fill your bowl with 2 inches of cold water.
Step 2: Gently put an egg into the water making sure that you do not drop it in.
Now you need to watch the egg to see how fresh it is.
- Egg stays at the bottom of the bowl and is lying on its side: Very fresh.
- Egg touching the bottom of the bowl but one end is slightly raised: Egg is still fresh.
- Egg stands upright but remains underwater: It is a bit older but still fresh enough to eat.
- Egg floats to the top: The egg is very old and could be rotten – you should throw away this egg.
There you have it – could it be any easier to do?
Is The Egg Float Test Real
Put simply, yes.
The egg float test works and is surprisingly accurate.
People who do this test a lot can tell you with great accuracy how many days old an egg is.
However for our purposes all we need to know is the basics, can we use the eggs or should we toss them? And the egg float test answers this questions with a simple but accurate guide to freshness.
Some folks will tell you that they can sex an egg by floating the egg however this is a myth that is right up there with the shape of the egg and the needle and thread method!
How Does It Work
While the test sounds like magic there are some simple physics at play.
When an egg is very fresh most of the space inside the shell is taken up with solid matter (yolk and albumin). A fresh egg only has a relatively small air sac at this time. Because of this when the egg is placed in water it will stay submerged because the egg is heavier than the water.
However because eggshells are porous, the older an egg gets the more air will enter the egg.
If you want to learn more about chicken eggs then read how do chickens make eggs? egg laying explained.
Over time the solid matter inside the egg will shrink, this leaves more room inside the egg for air. An egg that is very old will have little content since it will have dried, but it will have lots of air inside the shell.
Once enough air fills the inside of the shell the air will give the egg enough buoyancy to float.
When you place an old egg in the water it will float because it is full of air.
3 Others Ways To Tell If Eggs Have Gone Bad
There are a couple of other ways to tell how old your egg is.
The easiest is reading carton dates if you buy your eggs from the store. Each carton that the eggs are packed in comes with three pieces of information. These are the packing date, plant number and best by date.
Just keep in mind that the best by date does not mean that the eggs will be rotten, just that they are past their prime.
- The long number is the packing plant number.
- This three digit number is the day on which the eggs were packed (January 1st is day #1).
- The last one is the best by date. The eggs should be taken off the shelves by this date.
The second easy method is the plate test.
Simply crack an egg onto a plate and watch how it settles.
If the yolk sits bold and upright with a good color and the albumin (white) stays well held together, then your egg is fresh. If the yolk seems tired and slumped and the albumin spreads far and wide then the egg is old. If the egg is bad or rotten you will also be able to do the sniff test. The smell of a rotten egg is unmistakable.
Lastly, some people swear that shaking the egg will tell you how fresh it is.
The science behind this is suspect at best and I really would not rely on this particular test.
How Long Do Eggs Last For?
Generally store bought eggs will last for around five weeks if you keep them in the refrigerator.
Fresh backyard eggs will be good for around 3 months if you keep them in the refrigerator.
Why is there such a difference?
You need to remember that the eggs you buy from the supermarket are already at least a month old because of the storage and transit times.
If you want to keep eggs for longer than this you need to look at other storage methods. Water glassing keeps eggs fresh for up to two years (more on this later).
What Is The Best Way To Store Eggs?
If you buy your eggs from a supermarket then it is likely that your eggs came from a large egg producing enterprise.
These eggs are best stored in the refrigerator.
You should keep them at the back of the fridge because it has the most stable temperature. If for whatever reason you do not have a fridge, then store your eggs in a cool and dry place such as a cellar or pantry.
If you raise your own eggs you should probably still keep your eggs in the refrigerator for safety.
The biggest concern with storing eggs at room temperature is salmonella.
Salmonella will spread at room temperature and you do not want to run the risk of sickness in your household as salmonella can be deadly.
Other Ways To Store Eggs
Freezing: Freezing eggs is probably the quickest and easiest way to store eggs. Your eggs should be cracked open and now you can choose whether you want the yolks and whites separate or mixed together. Most people mix them up and decant into large ice cube trays for freezing. The larger cube trays hold just about one egg per cube. Eggs preserved like this will keep for about one year in the freezer.
Salt Cure: Salt cured eggs are an acquired taste and a small amount goes a long way so you really should not need many of them. Here is a nice little video on how to salt cure your eggs:
Oiling: This is a quick and simple way to extend the life of your eggs. Using warm mineral oil you should thoroughly coat the egg and place it pointy end up in a clean egg carton. You can keep these eggs in a fridge for up to twelve months. Just remember to turn the carton over once a month just to ensure yolk integrity.
Dehydration: There are several methods to dehydrate eggs but the easiest is the cook/dehydrate method. Scramble your egg in a pan and cook until done. Once they are cooked place them in the oven at 160°F for ten hours. Next you should blend them down to flakes or powder You can now store them in airtight containers.
Water Glass: Eggs preserved using this method can last for up to 12 months! The following video is a really nice clear and concise how to guide:
Pickling: I saved my favorite until last – there is nothing like a good pickled egg! Bantam or pullet eggs work really well for this. Start by hard boiling your eggs and letting them cool. Then you can peel them and place them into a Mason jar. You can add onions, beets and spices if you want. Cover them with your vinegar mix and put the lid on the jar and refrigerate for one week before you start to eat them.
FAQs about Eggs Going Bad
How long do eggs last?
If you keep your eggs in the fridge then they are usually good for 3-5 weeks.
Just remember that the longer you keep them the poorer the quality will become and the worse the taste will get.
My egg smells, can I eat it?
If your egg is smelly then you should not eat it.
Are eggs bad if they float?
An egg that floats is old and well past its prime. If you crack the egg and it gives off a foul odor then it is bad and needs to be tossed out.
What are the signs of a bad egg?
When you crack the egg you may see blood spots (small brown flecks), these are ok to eat.
However if you see any black or green spots, or a pinkish tinge to the yolk you need to toss those eggs out.
Should You Wash Eggs?
This very much depends on where you live.
In the UK, they advise against washing your eggs and yet in the US they recommend that you do.
Why is that?
In the UK all commercial flocks that intend to sell eggs should be vaccinated against salmonella. This is a nasty little bug that can cause profound illness (especially in young and old people).
Because these chickens are vaccinated their eggs do not need cleaning so the egg’s bloom is intact. The bloom will keep the egg safe so you do not need to clean it.
However, in the US flocks are not vaccinated so the eggs have to go through a commercial washing program to remove any bugs from the shell.
To be on the safe side you should wash your eggs whether they are from the supermarket or your backyard flock.
If you do wash your eggs then make sure you use water that is slightly warmer than the egg. If your eggs are only slightly mucky then you can use a scrubby to remove the dirt. If they are really gross then you should toss them out.
The egg float test is a very simple way to find out how fresh eggs are.
Last year I found an egg stash of twenty something eggs and I used the float test on them. All but two were fresh enough for eating and the test saved me from tossing out those useful eggs.
Testing for freshness in eggs is a must if you are baking things like meringue – the fresher the eggs the better the pie!
If you have eggs that are beyond their best you can feed them to your pets or back to the chickens as scrambled eggs.
So, enjoy your eggs and have fun experimenting with ways to keep them fresh over winter!
Do you want to learn more about chicken eggs? Read how long do chickens lay eggs.
Let us know any of your methods in the comments below…