There is described a beverage preparation machine comprising a centrifugal brewing unit (2) for preparing a beverage by centrifugation of an ingredient contained in a capsule and mixed with a carrier liquid, the centrifugal brewing unit (2) comprising a centrifugal cell (3) for receiving such a capsule (2A, 2B, 2C); driving means (5) for rotating the centrifugal cell (3); a regulator for regulating a rotation speed of the centrifugal cell (3) by controlling the driving means (5) based on a feedback signal representative of a difference between a desired rotation speed and a measured rotation speed of a capsule (2A, 2B, 2C) rotated in the centrifugal cell (3); the machine further comprising: liquid supply means (6, 4) for supplying carrier liquid to the centrifugal brewing unit (2); an optical reading arrangement (100) for reading a code on a periphery of a capsule (2A, 2B, 2C) while the capsule (2A, 2B, 2C) is rotated relative to the optical reading arrangement (100) in the centrifugal cell (3) and generating an output signal representative of the code; wherein the beverage preparation machine is 15 configured to compute the feedback signal using an output signal of the optical reading arrangement (100) representative of at least part of a code of a capsule (2A, 2B, 2C) read by the optical reading arrangement (100).