A method provides a rubber-elastic sealing member onto a capsule intended for producing a beverage in a beverage production device. The capsule has a body portion having a side wall and a flange-like rim portion. The rim portion extends from the side wall of the body portion. The method includes the steps of applying an uncured sealing composition in a liquid or viscous state onto the rim portion of the capsule, heating said applied sealing composition such that the sealing composition at least partially migrates towards the side wall until the sealing composition reaches the side wall, and curing the sealing composition after the migration towards the side wall.