Why Is Vinegar Added To Boiling Water When Cooking Eggs?


Recently, I was boiling up some eggs, and as I poured in a bit of vinegar, someone asked me, “why the heck are you adding that?” I had actually never even thought about why; I was just told a long time ago that it helped eggs boiled better. So, curiosity got the better of me, so I did some extensive research, and this is what I found out.

Vinegar is added to boiling water because it increases the acid pH levels so that when they cook eggs, the membrane holds the egg whites from spilling out of tiny cracks in the shell. Additionally, it serves to lower the temperature at which egg whites congeal.

You can count on white vinegar or apple cider vinegar to do the job. What you are looking for is a more acidic pH so that in case the egg cracks, the egg whites will stay in place. Let’s dive into the topic a bit more deeply.

Understanding Boiling Water And Eggs

Boiling Eggs in a Pot

Boiling an egg should be one of the easiest things you can cook. You just put an egg in boiling water and wait until it hardens, right?

Well, it is not the case for everybody. Some people struggle to create the “perfect” boiled eggs. If you’ve ever had a poorly cooked, rubbery egg, you know what I am talking about.

What Does Adding Vinegar do to eggs?

Vinegar’s pH falls somewhere between 2.5 and 2.8, making it an acid. As your eggs become more alkaline over the following days, adding a small amount of vinegar into the boiling water can make a difference.

Once the vinegar molecules interact with the egg membrane, it helps to harden the egg whites, making them stay inside the eggshell.

You should know eggs are never acidic. A fresh egg will have a neutral pH that will become more alkaline over time. That’s why the older the egg, the more likely it is to crack when boiling.

Does Vinegar Keep Eggs From Cracking?

Vinegar does not keep eggs from cracking. The purpose of vinegar is to is that if your water is to increase the pH level so that the eggs will congeal and not spill out of cracks.

How Much Vinegar Do You Put in Water to Boil Eggs?

The vinegar water ratio should be 1:24, one part of vinegar per every twenty-four parts of water. You can add two teaspoons of vinegar per cup of water.

Can I Substitute Lemon Juice in Place of Vinegar for Boiling Eggs?

Lemon juice can be used as a replacement for vinegar when boiling eggs since it is an acid as well. The ratio of lemon juice to water would be about the same as with vinegar; 1:24 lemon juice to water.

Does Vinegar Work in an Egg That Has a Crack Before Boiling?

Vinegar will help keep eggs from leaking even if it has a crack in it before adding the vinegar. However, if you notice the egg has a crack, you should discard it. The crack is a sign that the egg is not suitable to be consumed since it could have been exposed to bacteria.

How Long Do You Leave An Egg In Vinegar?

An egg only needs to stay in vinegar while cooking. You do not need to soak eggs in it before boiling. Just add a small amount of vinegar to the water right before boiling then cook them the allotted time.

What Happens If You Leave An Egg In Vinegar For Too Long?

If you leave an egg for too long the vinegar will weaken the eggshell until it’s gone. All you will have left is a soft uncooked egg without a shell. Therefore, immediately remove the eggs from the water immediately once they are done.

Does Vinegar Make Eggs Hard to Peel?

Vinegar does not make eggs harder to peel. While it is true that more acidic eggshells won’t leak fluid as easily, it won’t make the shells more difficult for you to crack or peel off. The hardness of the eggshell has nothing to do with the added acid.

Tips For Making The Shell Come Off Boiled Eggs Easily

Now that you know how to safely boil your eggs without spillage, here we have a few tips to easily remove the shells

How to remove boiled eggshells more easily:

  1. Put the eggs into ice water after boiling
  2. Add salt to the boiling water
  3. Add baking soda to the boiling water

Here is an alternative method that will work really well:

Why Some Eggs Crack When In Contact With Boiling Water

First off, you have to be careful when placing eggs in the pot. Do it too roughly, and there’s a risk they will crash into one another. The slightest crack is enough to ruin the result. Water will start to get through the eggshell, forcing the egg whites to come out. Once you are done cooking your eggs, you will notice the egg yolk remains inside. But what you have now is not an entire egg, and the whites that boiled outside the eggshell don’t seem appealing.

Cool Fact: Some people have seen eggs crack right after they get in contact with hot water. It usually happens with old eggs. Fresh eggs are more acidic than old eggs, which makes them harder to break.

These acids are inside the egg membrane, but you can say they “breathe out” through the shell. When you place a weakened egg into hot boiling water, it may crack because it cannot adapt to the low temperature quickly.

Ways To Avoid Spillage When Boiling Eggs

Now that you understand why eggs crack and how vinegar is an excellent solution for this, let’s see other options you have to prevent it:

Keep your eggs fresh.

It may sound cliché, but this is the easiest way to prevent cracked eggs. An easy way to identify how fresh your eggs are is to put them into cold water. Fresh eggs will sink. If the egg floats, it is likely to crack.

Start boiling in warm water.

Hot water is excellent for cooking boiled eggs quickly. But, the bubbles in hot water will make the eggs move around inside the pot. If you add them to warm water, there’s less risk that they will crack.

Place them tight in a small pot.

If your eggs lay tight inside the pot, there’s no space for them to crash into one another. Using a smaller cooking pot is an excellent option if you are boiling large quantities of eggs.

Use an electric egg boiler.

Electric egg boilers have become popular. They are easy-to-use appliances where you can safely cook your eggs. Most electric boilers allow up to seven eggs. Bigger versions of the product allow up to twelve eggs at a time. Additionally, you can choose other cooking styles such as poached, omelets, and scrambled.

Other Reasons Why People Add Vinegar To Eggs

Bottle of Vinegar with Glass Bowl in Front

There are other reasons why people add vinegar to eggs besides preventing leakage when boiling. For instance, we have pickled eggs, a recipe that requires hard-boiled eggs to be marinated for days in a combination of water, vinegar, and spices.

Another version of the pickled eggs is the red beet pickled egg. The preparation is very similar, but there’s an additional ingredient: beets. By adding beets to this method, the egg whites will change to a reddish color.

Why Does Vinegar Help Poached Eggs?

The acidity in vinegar helps you to have the perfect poached egg. When you poach eggs, you are looking for a soft yolk covered by egg whites. Vinegar helps you to keep the egg whites together while the egg yolk remains inside without overcooking.

Final Thoughts

If, by any chance, your egg cracks before it is fully cooked, water will get into the eggshell pushing the egg whites to get out. Vinegar helps you to have a more consistent boiled egg. It will kind of seal the crack, preventing spillage.

However, not all eggs will crack in boiling water. Some of the reasons this happens include:

  • You are using old eggs.
  • It could be that the pot you use is too big.
  • You added the eggs once the water was boiling.

There are other alternatives if you don’t want to use vinegar. For instance, you can get an egg boiler machine. These appliances are easy to use; you will open them, add water, place your eggs in the egg tray, close the lid again and press the start button.

If you strongly believe vinegar is a solution to this issue, remember to add two tablespoons of vinegar per cup of water.

Thanks for stoppin’ by!

For more, don’t miss Do Eggs Really Need to Be Refrigerated? | Storage Guide.

Anne James

Hi, I'm Anne but my grandchildren call me Jelly Grandma. I have over 50 years of experience as a Southern cook and am a retired librarian. I love sharing what I have learned. You can find me on YouTube as well! Just click the link at the bottom of your page. I hope your visit here has been a sweet one.

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