A beverage preparation apparatus for preparation of a beverage from a capsule in a clamp assembly (30). The clamp assembly has a first clamp member (31) and a second clamp member, where the inner surfaces of the first clamp member and the second clamp member form a clamp chamber (33) for substantially enclosing and supporting a capsule (10) during beverage preparation. The second clamp member comprises a rigid peripheral frame (32) having a central void and a resilient layer (37) extending across said central void. There is a piston (36) positioned in the central void and resiliently coupled to the peripheral frame (32) to allow limited resilient movement of the rigid peripheral frame (32) relative to the piston (36).