A device for preserving a product for beverage preparation comprises a first package (4,4') having a first constant of oxygen permeability (K 1 PO 2 ) wherein said product is sealed, that is housed in a second sealed package (5,5') having a second constant of oxygen permeability (K 2 PO 2 ), the first constant of oxygen permeability (K 1 PO 2 ) being greater than the second constant of oxygen permeability (K 2 PO 2 ), moreover, an oxygen absorbing material (6) is housed in second package (5,5') together with the first package to remove oxygen from the first and second package (4,4').