Coffee maker, eggs, a cup of coffee, and coffee beans
The Reason Swedish Egg Coffee Is Brewed With The Shell
In Swedish egg coffee, a.k.a. Scandinavian egg coffee, "church basement coffee," or Nordic egg coffee, eggs and eggshells don't add flavor or texture, but act as a natural filter.
Swedish egg coffee isn't from Sweden. While some claim it originated on American soil, others say it was developed on the way from Sweden to America in the late 19th century.
It’s possible that the coffee grounds and water back then weren't up to par, as eggs were added to clarify this coffee in a manner similar to crystal clear consommé.
In the case of Swedish egg coffee, the eggs filter and cling to any solids and impurities, making it noticeably smoother and less bitter than a standard cup of joe.
To make Swedish egg coffee, bring some water to a boil and mix coffee grounds with a cracked egg in a bowl. Crush the eggshell up a bit, add it to the bowl, and mix everything.
Once the water starts boiling, add the coffee-egg mixture and lower the heat until it simmers. Turn off the heat after a few minutes and let it sit before adding in cold water.
Once the solids sink to the pot’s bottom, strain the coffee and toss the solids. While the eggs remove impurities, the eggshells’ calcium dilutes and reduces the coffee’s acidity.