Kortum was born as Erika Bendfeldt in Neustadt, Schleswig-Holstein, Germany on 7 January 1912. She grew up on a farm, and worked in the fields throughout her childhood. Her mother became very ill, and she recalled her community always being there for the family.

Kortum’s husband was wounded during World War II, and later succumbed to his injuries. She had vivid memories of the 3 May 1945 SS Cap Arcona bombing, taking in survivors of the destroyed ship.

Kortum was vaccinated against COVID-19 shortly after her 109th birthday, being one of the oldest people to receive the vaccine. She died on 10 February 2022 at the age of 110 years, 34 days. She is among the top 10 oldest people to have died in Schleswig-Holstein.