Unless you carry around your own beans everywhere you go — and I know people that do — chances are you will one day find yourself in a situation where only cheap, bitter coffee is available. Luckily, there is an easy way to turn bitter coffee into a rich, smooth brew. You just need an egg.
According to Eater, egg coffee has actually been around for a while, and it’s made by mixing a beaten egg into coffee grounds, boiling the mixture and letting it all steep for 10 minutes. There’s no need to strain, as the egg and grounds will congeal together on top, forming a kind of plug. When a coffee-cup’s worth of cold water is added to the mix, the plug is pushed down to the bottom of the pot, taking the grounds and bitterness with it. To understand how this works, you have to understand the egg:
Egg whites, or albumen, are a powerful clarifying agent utilised in both making consommé and pulling sediments out of red wine. When egg whites are subjected to high temperatures — as in boiling — their proteins break apart. Those newly separated proteins then bind to other macromolecules that might be present in the liquid — like tannins (in wine), cellular material (in consommé), or other impurities that can cause bitterness.
The result is a lush, light-coloured cup of coffee with a “round richness completely devoid of bitterness”. Bonus: You don’t need any fancy equipment, which means you can have smooth, tasty coffee pretty much anywhere, even camping.