Purpose The purpose of this paper is to offer an insight into the fundamental changes taking place in Port wine production value chains. Specifically, the authors examine two distinct production regimes: when Port is aged and sold in the Greater Oporto and, alternatively, when it is produced, aged and sold in Douro. Design/methodology/approach The authors apply a tri-regional input–output model (Douro, Greater Oporto and rest of the country) for Portugal’s economy. This framework comprises a significant level of detail, with 431 products and 136 industries, the corresponding supply and demand for the products, by industry (for intermediate consumption) and final demand. Findings This study shows that the two regimes generate noteworthy, but quite heterogeneous, regional impacts. In both cases, the distribution of value added generates international and interregional trade flows. Moreover, the study reveals a greater capacity to capture national value added by getting the supply chain more intensive in localised services and by using state-of-the-art production techniques. Originality/value Using detailed regional data, the authors use disaggregated information, both for industries as well for territories, overcoming a common limitation in similar works that are grounded in international databases. Additionally, the approach integrates the trade interactions among industries and regions, which proves essential to uncovering spillovers resulting from the (direct and indirect) use of inputs from other regions and other countries.