Helmut Coffee Roasters is a cafe in the residential streets of Sadang-dong, a five-minute walk from Sadang Station, where coffee is roasted and brewed on site. Its signature Mafia Einspänner comes in warm or cold versions, alongside Bambino flat white, Levain cookies and cake. On the second floor there is a table by the window suited to using a laptop, and an indoor restroom is available. Around 9:30 to 10 p.m., the sound of the roasting machine being cleaned becomes loud and makes conversation difficult.