Cup of coffee on a small plate with cream biscuits
You Can Actually Fix Bitter Coffee With Eggshells

NEWS

By MATTHEW LEE
Eggshells next to ground eggshells in a pestle and mortar
Letting crushed eggshells sit in a bitter cup of coffee for a few minutes before straining the drink can counter its bitterness like magic, and there’s a scientific reason why.
Cup of coffee next to coffee beans
Coffee is harsh and bitter due to a range of acids called chlorogenic acid lactones. A primary chemical is needed to "soak up" that acidity and lower the coffee's pH.
A pile of eggshells
Eggshells are primarily made of calcium carbonate, which is alkaline and can absorb all bitter, acidic compounds to transform the brew back to its smooth, mellow taste.
Coffee beans and a cup of coffee
However, per America's Test Kitchen, this hack can sacrifice the complexity of the coffee's flavor, so it's better suited for cheap coffee grounds than specialty ones.
Hand feeling hard boiled egg
The shells of boiled eggs are preferred as most of their impurities are eliminated in the water. Shells from raw eggs sanitized with a soak in vinegar and water will work, too.
Had boiled egg peeled halfway
Eggshells can be crushed using a pestle and mortar. One egg yields enough shell bits for about four cups (a pot), so sprinkle your java accordingly.