The certification of artisanal productions is included in the National Certification System for Traditional Craft Productions published in the Decree Law 121/2015 of June 30th.

At the request of the Municipalities of Gondomar and Póvoa de Lanhoso, the process began with the preparation of a specification book, created by the Associação Portugal à Mão, approved by the Commission led by the I.E.F.P. (Institute of Employment and Vocational Training). A Geographical Indication registration was then made at INPI (National Institute of Industrial Property). Certification is carried out by an impartial entity, A.CERTIFICA, a certification body (O.C.) accredited by IPAC (Portuguese Accreditation Institute). All Craft Production Units (UPA's) that are candidates for having their production certified are visited by a Technical Commission made up of two O.C. Control Agents. (a quality technician and another specialist in the art).

Each UPA is assigned labels, numbered and with a hologram, to be placed on each certified piece. The hallmark directly on the piece is carried out by the INCM (Imprensa Nacional Casa da Moeda) - Assay Office, which guarantees to the consumer that it is a unique piece, produced by hand.