Beverage preparation machine comprising: - a centrifugal brewing unit for preparing a beverage by centrifugation of an ingredient contained in a capsule and mixed with a carrier liquid, said centrifugal brewing unit comprising: - a centrifugal cell for receiving such a capsule ; - driving means for rotating said centrifugal cell ; - a regulator for regulating a rotation speed of said centrifugal cell by controlling said driving means based on a feedback signal representative of a difference between a desired rotation speed and a measured rotation speed of a capsule rotated in said centrifugal cell ; the beverage preparation machine further comprising: - liquid supply means for supplying carrier liquid to the centrifugal brewing unit ; - an optical reading arrangement for reading a code on a periphery of a capsule while said capsule is rotated in said centrifugal cell relative to said optical reading arrangement and generating an output signal representative of said code; wherein said beverage preparation machine is configured to compute said feedback signal using an output signal of said optical reading arrangement representative of at least part of a code of a capsule read by said optical reading arrangement , characterised in that said beverage preparation machine is configured to determine, from said output signal of said optical reading arrangement representative of at least part of a code of a capsule read by said optical reading arrangement , a value representative of said measured rotation speed on the basis of a bit period of a single bit of said code. - a centrifugal brewing unit for preparing a beverage by centrifugation of an ingredient contained in a capsule and mixed with a carrier liquid, said centrifugal brewing unit comprising: - a centrifugal cell for receiving such a capsule ; - driving means for rotating said centrifugal cell ; - a regulator for regulating a rotation speed of said centrifugal cell by controlling said driving means based on a feedback signal representative of a difference between a desired rotation speed and a measured rotation speed of a capsule rotated in said centrifugal cell ; - a centrifugal cell for receiving such a capsule ; - driving means for rotating said centrifugal cell ; - a regulator for regulating a rotation speed of said centrifugal cell by controlling said driving means based on a feedback signal representative of a difference between a desired rotation speed and a measured rotation speed of a capsule rotated in said centrifugal cell ; the beverage preparation machine further comprising: - liquid supply means for supplying carrier liquid to the centrifugal brewing unit ; - an optical reading arrangement for reading a code on a periphery of a capsule while said capsule is rotated in said centrifugal cell relative to said optical reading arrangement and generating an output signal representative of said code; - liquid supply means for supplying carrier liquid to the centrifugal brewing unit ; - an optical reading arrangement for reading a code on a periphery of a capsule while said capsule is rotated in said centrifugal cell relative to said optical reading arrangement and generating an output signal representative of said code; wherein said beverage preparation machine is configured to compute said feedback signal using an output signal of said optical reading arrangement representative of at least part of a code of a capsule read by said optical reading arrangement , characterised in that said beverage preparation machine is configured to determine, from said output signal of said optical reading arrangement representative of at least part of a code of a capsule read by said optical reading arrangement , a value representative of said measured rotation speed on the basis of a bit period of a single bit of said code. <EOS>