A lot of the time it’s easy to tell when food has gone bad. There will be characteristic discoloration, a change in texture and of course some foul odor. But this won’t always work with eggs, and duck eggs in particular.
If you don’t crack open the egg, it will look pretty much as it always has no matter how old it happens to be. This could lead to a seriously unpleasant surprise when it comes time to cook with them. So, how can you tell if duck eggs are bad?
You can spot a bad duck egg by looking for cracks, being alert for foul odor or seeping fluids, and paying attention for an off or nasty taste. You can also perform an egg float test which will show you if the egg is merely old or actually spoiled.
It turns out you don’t have to crack open a questionable duck egg only to find out it’s gone bad in the worst way possible. By inspecting closely and being cautious, you can usually tell well before it is time to start cooking.
Keep reading, and I’ll tell you a lot more about how to detect spoilage in your duck eggs.
How Long Do Duck Eggs Actually Last?
Duck eggs can last a couple of weeks in dry, cool storage or up to 6 or 8 weeks in the refrigerator.
Duck eggs are known to have a longer shelf life than chicken eggs due to their thicker shells which help to slow the loss of moisture and intrusion of air and other contaminants…when stored properly, of course!
However, it’s important to note that the overall quality and freshness of the eggs will start to decline after just a few weeks even in the refrigerator, so using them sooner rather than later is a smart move.
Factors that Affect Egg Shelf Life and Quality
There are several variables that will affect the shelf life and overall quality of duck eggs…
Storage conditions are, as always, a big one. Keeping duck eggs at a consistent cool temperature is crucial for maintaining their freshness.
Storing them in the refrigerator at a temperature between 35°F and 40°F is ideal, but they will generally keep fine in a root cellar or other “cool” storage for a couple of weeks.
In the fridge, avoid placing them near the door, as temperature fluctuations can cause the eggs to spoil faster.
Humidity also helps preserve your duck eggs as this helps prevent moisture loss. The ideal humidity level is around 75%, but you can get by with less. Just know that drier conditions accelerate spoilage.
You can increase humidity “locally” by placing a damp cloth or a container of water in the refrigerator where you store the eggs.
Also, though it seems counterintuitive, avoid cleaning your eggs: Washing duck eggs can remove the natural protective coating called the bloom that helps keep bacteria out and moisture in.
It’s best to clean them only when you’re ready to use them, using warm water immediately prior to cracking and cooking. And lastly, be gentle when handling duck eggs to avoid cracks or damage that can lead to rapid spoilage.
When you set out to collect your eggs, use a clean basket or container and place them carefully in a single layer to prevent breakage.
How Can You Tell the Difference Between Fresh and Spoiled Duck Eggs?
While it is true that you might know a spoiled egg as soon as you see it (after cracking), it’s much better to try and spot it before that point.
Luckily, there are several easy-to-recognize indicators that can help you differentiate between fresh and spoiled eggs.
- Shell Color: Fresh duck eggs typically have a uniform color, ranging from white to pale blue or green. A change in color or the presence of odd dark spots on the shell may indicate bacterial growth or spoilage.
- Eggshell Cracks: A cracked shell means the egg’s contents are exposed to bacteria, leading to spoilage. Inspect the eggs carefully for any signs of cracks or damage before using them and never trust a cracked one!
- Other Visible Damage: In addition to cracks other visible damage like dents or other irregularities in the shell can also indicate a high likelihood of spoilage- or just poor quality.
- Leaking Fluid: If you notice any fluid leaking from the eggshell, it’s a clear sign that the egg is compromised or highly suspect and should not be consumed. Don’t do it!
- Texture: The contents of a fresh duck egg will have a firm, plump yolk and a thick, viscous egg white that is translucent. If the yolk appears flattened or the white is watery, it’s likely that the egg is no longer fresh.
- Odor: Always a big one. Any strong, unpleasant odor is a telltale sign of a spoiled egg. Fresh duck eggs should have little to no smell when cracked or uncracked. If you detect any sulfur-like or rotten smell when cracking the egg, discard it immediately. Also, sniff an intact egg closely; you might be able to detect that telltale nastiness through the shell in some instances.
What is Air Cell Size?
The air cell is a small pocket of air located between the inner and outer membranes of an egg, usually at the larger end.
When an egg is laid, it contains a small air cell due to the difference in temperature between the hen’s body and the cooler environment.
As the egg cools, the contents contract, creating a vacuum that pulls air through the porous shell and forms the air cell.
Over time, the air cell size increases as the egg loses moisture and carbon dioxide through its porous shell. This process causes the egg white and yolk to shrink, making the air cell more prominent.
The size of the air cell can be a reliable indicator of the egg’s freshness, with smaller air cells signifying fresher eggs and larger air cells indicating older or potentially spoiled eggs.
Using the Float Test to Differentiate Between Fresh, Old and Spoiled Eggs
The float test is a simple and effective method to determine the freshness of duck or chicken eggs. Simply by observing how the egg behaves in water, you can easily differentiate between fresh, old, and spoiled eggs.
To perform the float test, fill a deep bowl with water and gently place the egg in it: A fresh egg will sink to the bottom of the bowl and lay flat on its side. This is because the air cell inside the egg is small, indicating that the egg has been laid recently.
An older egg may still be safe to consume but will not be as fresh. During the test, an old egg will sink to the bottom but stand upright on its end. This is due to the air cell expanding over time as the egg loses moisture.
And as you probably deduced, a spoiled egg will float on the surface of the water or in the middle of the glass. This is because the large air cell inside the egg has expanded significantly, causing the egg to become buoyant.
Floating eggs are very dodgy, and should be discarded or eaten only after cracking them separately and examining them closely.
Trust Your Nose: Rotten Smells Are Bad News
Trust your nose! Your sense of smell is a powerful tool in determining the freshness of duck eggs. Fresh eggs should have little to no odor, while spoiled eggs produce a seriously unpleasant or downright nasty smell.
If you detect a sulfur-like or rotten smell when cracking a duck egg or even while it’s still in the shell, discard it immediately, no questions. Consuming spoiled eggs will likely lead to foodborne illnesses.
Don’t Ignore Odd or “Off” Flavors, Either
In addition to the appearance, texture, and smell of duck eggs, it’s also important to pay attention to their taste. If an egg has an odd or “off” flavor, it could be a sign that it has started to spoil.
Spoiled eggs may taste sour, metallic, rancid, or just “off” somehow (hard to describe, but you’ll know) due to the presence of harmful bacteria or the breakdown of fats and proteins.
To ensure that you’re enjoying fresh and safe duck eggs, always check for signs of spoilage, according to the methods I talked about above, before consuming them.
Trusting your senses and being vigilant about egg quality will help you make good decisions about their consumption and reduce the risk of getting sick.
Tom has built and remodeled homes, generated his own electricity, grown his own food and more, all in quest of remaining as independent of society as possible. Now he shares his experiences and hard-earned lessons with readers around the country.
Find out more about the team here.