Yes, you read correctly. Eggshells.
Why Add Eggshells in Your Coffee
This old trick dates the to early 1900s and it’s meant to get rid of the bitter taste of coffee. Such taste is usually attributed to over-extraction of the coffee ground, or to the use of cheap beans. Either way, using an eggshell can really help settle the grounds of the coffee and improve the overall taste.
I love coffee, but I’m very picky. I know exactly what I like and wouldn’t settle for anything less. While I was adamant to satisfy my taste buds, I missed out on many excellent cups of coffee:
- Coffees rich in aroma often didn’t taste as great as they smelled.
- Coffee at a campsite seemed inviting on a cold day, but the cheap coffee grounds we used ruined the taste for me.
- The coffee I forgot on the stove that brewed too long usually had to be thrown away.
What put me off? The bitterness. Some may call it an acquired taste, but no matter how long I drank coffee, it never attracted me.
And then, luckily, a barista taught me about eggshells.
How it Works
When you taste that bitterness in your mouth, you’re actually tasting the coffee’s acidity. What do you need to counter that? An alkaline substance.
Eggshells are alkaline because they’re made of calcium carbonate. They’re also practical because you can easily mix them with coffee grounds. During the brewing process, the substances will have chemical reactions. The alkaline substances absorb some of the acids, leaving you with a better brew.
Ready to take your cup of coffee to the next level?
What to Do
Of course, what you don’t want is coffee that tastes like eggs. So let’s get this process right.
Get the Shells
Unfortunately, you cannot boil the eggs to easily shell them. When the egg cooks it sparks another chemical reaction with sulfur as a result. Believe me, that’s one flavor you don’t want in your coffee.
So you need to crack open raw ones and tip out the eggs.
Clean the Shells
I list this as a specific task because you don’t want egg flavoring in your coffee. Wash the shells thoroughly to ensure there aren’t any dried egg or dirt on them.
Break Them Up
Now you can grind them up. Breaking them up into small pieces allows for more chemical reactions to take place.
But don’t go overboard. You don’t want them so small that they filter through and end up in your cup.
Add them to Your Grounds and Brew
No matter what process you use, simply add the shells where you add the grounds. If you use a coffee maker the filter will block the shells. If you’re brewing grounds at the bottom of a kettle the shells will actually prevent the grounds from floating to the top, so it’s easier to pour your next cup.
Throw Them Away
It’s not advisable to reuse the shells. Firstly it will be tricky picking them from the used coffee grounds. Secondly, you need new shells if you want the same kind of chemical reaction.
Now pour your cup, take a sip and enjoy the acid-free taste.
How Many Eggs do You Need?
In general, one egg’s shell is enough for four or fewer cups of coffee.
Try and Try Again
If you’re as picky as I am, you’ll need to experiment. Adjust the number of shells you use until you get the perfect coffee to shells ratio.
I’m glad I could be of assistance. Enjoy.
Anthony is a professional barista in the city of Chicago. He has written for many online publications on various topics related to coffee.
Do eggshells really reduce the acidity in coffee?
The short answer is yes. Eggshells are essentially calcium carbonate which dissolves in acids.
Another way to reduce the acidity is by adding salt in your coffee.