A device for preserving a product for beverage preparation comprises a first container (4,4′) having a first constant of oxygen permeability (K1PO2) wherein said product is sealed, that is housed in a second sealed package (5,5′) having a second constant of oxygen permeability (K2PO2), the first constant of oxygen permeability (K1PO2) being greater than the second constant of oxygen permeability (K2PO2), moreover, an oxygen absorbing material (6) is housed in second container (5,5′) together with the first container to remove oxygen from the first and second container (4,4′).