3 Ways to Perform an Egg Freshness Test

Use These Fresh Egg Tests to Avoid an Encounter with a Rotten Egg


fresh chicken eggs

You may wonder why anyone would need to perform an egg freshness test since most people raising chickens for eggs check the nesting boxes every day. If you have ever opened a rotten egg, you will never want to do that again! There have been two instances that required me to perform an egg freshness test to determine whether the egg was fresh, fertile or rotten. 

The first situation was when my Black Australorp hen, Mammie, had been setting for about 16 to 17 days. I noticed she had rolled three eggs out of the chicken nesting box. I knew she would do that if the eggs were bad, but me being me I thought, “Well, she might not have meant to do that. Maybe she was just turning them and they flipped out.” So … I put the eggs back. The next day she had two of them out again. So I decided to check them and sure enough, they were rotten.

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The second situation was when about half of my free-ranging backyard chickens were young hens. I thought they would see the older hens go back to the nest to lay and follow suit, but of course they didn’t. One day we were out moving some limbs and surprise! We found a nest of about 26 eggs. I had no way of knowing how long those eggs had been there, so I had to determine which eggs were good and which were bad.

Float Test


I used the float test. While the float test is not 100 percent accurate, it has proven accurate enough for me. I use a 1-gallon bucket to do my float test. I fill the bucket 3/4 of the way full with water then add the egg(s) in question. Fresh eggs will lie on their sides on the bottom of the bucket. When an egg is a few days old, it will have one end that tips upward at a slant; if the egg is stale, it will stand on its end; and if the egg is rotten, it will float to the top. Any egg that floats in any way, shape, or form, I call it rotten. The way this works is that the air space at the large end of the egg enlarges as the egg ages and that airspace causes it to float.

Bowl Test


The bowl test is considered to be the simplest way to perform an egg freshness test. Usually, a bad egg can be determined without completely breaking the shell. It’s harder to crack because the membrane has become tough. It will smell bad even from the outside and just as you barely crack it, stinky thick rottenness will ooze out. Some eggs are harder to determine by examining them and you just have to use the bowl test. You’re bound to get surprised from time to time. An egg that looks dirty and old will turn out to be fresh and one that looks fresh will turn out to be old. If the egg I crack open doesn’t have a funny smell, has good color, and the egg white is clear, I go ahead and use it.

But always use the mantra, “If in doubt, throw it out.” If you’re checking more than one egg at a time, be sure to rinse the bowl really well if a rotten one is found. One time my grandmother was cracking eggs and an undeveloped chick plopped out into the skillet. It was gross and smelled horrible. She said, “Well, that’s why I should be using a bowl.”

Candle Test



According to the old-timers, candling chicken eggs is the most reliable way to perform an egg freshness test. They tested the egg with a candle, that’s how the test got its name. The same effect is achieved by shining a powerful light through the egg while in a dark room. You can buy a candling station, but a good flashlight or even a candle will work in a dark room. Remember that the darker the egg shell, the harder it is to see. There is no way to tell if an egg is fertile or not without candling it. If the egg is fertile, you will see a spider like formation which is really just blood vessels forming. Personally, I don’t candle to determine fertility, I leave that up to nature. To perform the candle test, shine the light source next to the large end of the egg and you will see the inside of the shell illuminated. If the contents do not fill the shell, the egg is not exactly fresh. The larger the air pocket, the older the egg. In a fresh egg, the yolk doesn’t move about freely because the air space is small. In an older egg, the yolk will move around more freely. 

Do Eggs Go Bad

So now you have an answer to ‘do eggs go bad?’ They definitely do, but these three egg freshness tests will help you avoid an encounter with a rotten egg. Personally, I’ve always used the float test, and I’ve never had a problem. Have you ever had a situation where you needed to determine if an egg was fresh or not? How about an experience with rotten eggs? I hope you find these tips useful. Be sure to share your experiences with us in the comments or by using the contact me page on our site. Be sure to check out all the other helpful articles you can find on The Farmer’s Lamp.

Originally published in 2014 and regularly vetted for accuracy.

  • is there a book or video that tells how do chickens actually breed?

  • Steph M.

    I found some conflicting and confusing information. Commercial eggs are frequently dated to “Use By” a month or more after purchase. I don’t know how long it takes from lay to store for purchase, but I imagine it’s frequently not just a day or two. On the photo of the egg in water, the script reads that the egg is “slightly tipped on end and at a slant… is a few days old and should be used soon.” I used the float test on some commercial eggs before our chickens started laying. Some of the eggs that were well over a month old – according to package dating – still didn’t float, but a few out of the 18 I tested did sit upright on the bottom of my clear jar. The water was twice the depth of the eggs.

    The article also states “Usually, a bad egg can be determined without completely breaking the shell. It’s harder to crack because the membrane has become tough.” I don’t have a lot of experience with ”bad” farm eggs this time having had chickens, ducks, and guinea fowl in the past. We have only chickens now, but I’ve found that the membrane in old eggs seems less tough.Commercial eggs have very thin membranes.The farm eggs’ membranes are very tough in comparison, even on the day they’re laid, and don’t seem to change up to two weeks later.

    As far as experience with a rotten egg? Yes. When my kids were little and we had the mini poultry farm, they wanted to do the experiment with eggs and vinegar. (Put the egg in vinegar to see that the vinegar dissolves the shell.)

    They found 3 guinea eggs and put them into small glasses with vinegar. I don’t recall how long this lasted, but they were greatly entertained by how the eggs felt with only the membrane left on the outside. However, while the boys were eating breakfast and I was finishing up their school lunches, I heard a “pop” like that of a breaking light bulb. “Mommy, look!” One of the guinea eggs had literally exploded, taking rotten egg – along with the mess and SMELL – up to 8 feet across the kitchen. That was nasty cleaning the mess and airing the house in the Pacific Northwest early winter.

    Thanks for “listening,”

    • Rhonda C.

      Linda, Thanks for taking the time to share your experience with us. As far as the commercial egg “Use By date,” Lisa at Fresh Eggs Daily had an awesome article on that subject. Here’s the link for you: http://www.fresheggsdaily.com/2016/01/how-old-is-average-supermarket-egg.html

      I’m sorry I can’t account for the differences you found in your float tests and my experience and research. It’s often hard to tell angles and depth in a photo. There are many differences in commercial eggs and farm fresh. The membrane differences, I believe, are due to the fact commercial eggs have the bloom not only washed off, but chemically removed as the eggs pass through several washings. Removing the protective coating changes the egg and allows some of the liquids to pass through the shell to the membrane, altering it. Because we don’t wash our eggs, the membrane stays in it’s natural state.

      You’re right, an exploding rotten egg is terrible and 8 feet is a great distance. I’m sure it was a mess to clean up. Thanks again for your comment.

  • Thanks for this great summary. I have a lot more confidence in your down-to-earth descriptions than in a dozen identical internet “how to” or “help” sites.

  • I found a small clutch of eggs from one of my hens that wouldn’t return to the chicken pen, she had 16 eggs. I thought they must be okay, they were in a shaded area, so I brought them in and put them in some egg crates. About a week later, I decided to check them out and notice that a few were light and I shook one and I could feel the yolk going back and forth. I checked the bunch and 11 shook. So I put them in a plastic bag and put them in the trash in the kitchen. That evening we heard popping noises coming from the kitchen. They were exploding in the trash bag. I am SO glad I put them in a separate bag and had tied it off before putting them in the trash. We took them out to the trash can and thankfully we avoided the smell. I candled the remaining and found two more were questionable. I shake first now, lol, just in case, when using, but will I think the bowl idea is good so that I do not miss a bad one.

  • I was born and raise in Tampa, Fl, and although I have now lived in a VERY small rural Southeast Ga town longer than I actually lived in Fl I still consider myself a city girl at heart. That being said, when my youngest son was in the 8th grade he became involved in 4H and FFA which in turn got me involved! I know I’m showing my ignorance, but up until this happened I had never seen any kind of farm animal ( any animal really!) outside of a zoo! HA! Now we have chickens wandering around are yard, pig’s (in their stall’s, thank you VERY much!), the obligatory cats and dogs, and until recently we had rabbits and goats. Once upon a time I thought I would be out of this town quicker than you could say “Happy Graduation”! But hard as it is to believe, you could not drag me back to my big city! Not only has it opened my eyes to SO many fantastic and amazing miracles (one of our goats actually had a baby, kid?, on Easter Sunday, how COOL

  • I know I got a little off track, but I feel that kid’s today need ways, productive, healthy ways, that they can get involved in that not only keeps them out of trouble but opens up all sorts of opportunities for them. My son, who actually just graduated, chose to show pigs and I can’t begin to tell you how rewarding that became, not just for him but for our entire family. It not only kept him busy, hopefully busy enough to keep him out of some of the things that lots of his friends have found themselves in, but it helped teach him responsibility for something other than himself and it opened up doors to so many opportunities he may not have otherwise even been aware of. Again, I know I got off track, but I actually do have a few questions about the Float Test. Obviously, if they float, they’re foul and need to be tossed. Now if the egg is a few days old and tilts at a slant or if it’s stale and stands straight up how long will they be “usable”? I know I should have started with this question (sorry!) and I also feel like my City is showing, but is there another way I may have missed, to let me know how long the “few day old” and “stale” eggs can last in the fridge? I don’t want to have to keep doing the Float Test. Thank you for your patience with my ramblings, but if it helps even one kid get involved in 4H of FFA instead of some of the less productive endeavors, I will be very grateful. And thanks in advance for any advice you may be able to give me. PS: Although not related (sorry!) we are about to be the proud parents of some very cute, I have no doubts, Duroc piglets. Like I said, I know it’s not related but I am VERY excited and this will also give another young man (my 7 year old nephew) an opportunity to get involved in the “PIG LIFE”!

  • I have back yard chickens and the eggs last longer than a few days. I just tested some the other day that were a lot longer than a couple days and they still sank to the bottom! Also if you are not washing the bloom off and keeping them intact until eating you would have to test them right before you use them. I sell my eggs and I know I have not had a bad one that has been a few weeks old. The store eggs last way longer than a few days! Although your tests are good, I don’t agree with the few days old and hurry to use!

  • Hi, I cracked open a egg the other day,from one of my hens,and when I did the yolk was a little bit on the reddish side, and the part that’s suppose to be like clear in color was not.it was like white and runny. What did this mean, other then being no good?

  • Nice write-up on the methods! I hear the float test recommended a lot, but I’m not totally clear on how the “float test” is more useful, easier, or simpler than candling. Doesn’t a float test simply use buoyancy to approximately indicate the size of the aircell and thus the degree of shrinkage of the contents by evaporation? Candling with a flashlight or any bright, cool light (i’ve been known to use a phone flashlight) can quickly and easily allow you to actually SEE the size and shape of the aircell as well as spot anything else weird like an embryo or advanced rot–without getting the eggs sopping wet and potentially spreading taint from any rotten eggs to the fresher eggs or compromising the protective bloom. An ordinary flashlight will at least show the aircell in all but perhaps the darkest of chocolate brown eggs. Besides, candling is a simple skill anyone with layers should learn. Am I missing something though…?

  • I don’t refrigerate until I wash the eggs, so I have had some bad eggs at times. I have faith in the float method.

  • Sorry, but the hard to crack just doesn’t add up. I collect and eat eggs every day and my egg shells are not only harder than store bought eggs, the membrane is tough as well. these hard to crack egss are NOT old. People who have had my eggs that were not even 3 days old tell me the same thing.

    • I agree with you about the hardness of the newly laid eggs. Some of mine have thick hard shell. Sometimes it almost hard to crack. You kind of have to really hit it on the side of the bowl or pan several times. The shell is thick and the membrane is thick, but it is newly laid that day so I know it is fresh.This is why I didn’t understand the info on eggs being hard to crack are old. Thanks for your info.

  • I purchased eggs from a friend who raises them in her backyard. The shells are quite thin, and the yolks break immediately when cracking into a pan. They do sink to the bottom of a bucket of water, laying on their sides. And they don’t smell, and they do taste good. Why are the shells so thin? And why do the yolks break so easily?

    • Pat M.

      Could the eggs be from older hens? The older our hens got, the thinner the shells were. We got our first hens from an egg farm in the area who got rid of their layers when they reached 2 – 2 1/2 years old. They said production started to reduce after that age.

  • I had a game hen that would lay eggs in my goat’s shelter. Every day she’d chase the old goat out. Once she laid her (fertile) egg she would leave and the goat would sit the eggs. My pygmy goat successfully hatched out 7 – authentic barn yard mix chicks. Fortunately I had a benevolent barred rock hen willing to adopt.


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