The invention relates to a device for hydrating with a liquid sample, the device comprising a container (4) for receiving at least one liquid sample, and a lid (5) possessing a bottom face (51) having at least one hydrating support (3) fastened thereto to present an absorption face (31) for absorbing a liquid sample. According to the invention, the container (4) presents, by means of at least one well (6), a calibrated volume for receiving a liquid sample, the at least said well presenting a hydrating calibrated open section for hydrating a hydrating support (3) defined by the top edge (8) of at least said well (6), the hydrating calibrated open section possessing an area that is less than the area of the absorption face of the hydrating support (3) in order to control the absorption by capillarity of the liquid sample by the hydrating support.