None of the numerous food products that comprise the Italian food tradition can boast of business revitalisation as much as that which involved the wine industry in Italy and in the rest of the world in the last decade. This is not the appropriate moment to consider the reasons for this change, nor is it the right place to compare the industrial situations of that time with those present today. Rapidly covering the field of the extensive history of the wine business, it is sufficient to cite certain simplified facts in order to show how the end user of the product -the consumer -has dramatically changed his consumption history, which initiated the process of regeneration of the business, a process never before seen, in the world of agricultural industries. The companies in the vine-growing and wine-making business have been both the driving force and the beneficiaries of this state of affairs. Indeed, to have a clearer picture, a hypothetical external person, observing the wine business panorama today, would notice clear features and company models, that are unrelated to the historical past of the industry.

Purpose of the paper: The aim of this paper is to investigate how firms develop the transition from closed to open innovation and how this process occurs throughout R&D project networks.Methodology: The work carries out a multiple case study analysis of 8 Tuscan companies that have developed R&D projects in inter-organizational networks during the period under analysis. It investigates the opening of the innovation process starting from the firms' ego-networks over a period of several years.Findings: Results show that small and medium firms are not lagging behind large firms in the adoption of open innovation practices and that the industry where firms operate is not a discriminating factor for opening up of firms' innovation process. Besides, the technological complexity of the production process that companies adopt is one of the main determinants in the implementation of open innovation practices.Research limits: The study deals with temporary project networks, which represent the tip of the iceberg of the relational innovation processes of the analyzed firms.Practical implications: The study underlines the importance of opening an innovation process outside of the boundaries of the firms through the privileged tools of temporary R&D networks that are financed by public policies. Managers and entrepreneurs should carefully dedicate resources and competences to this process, in accordance with the increasing relevance of the open innovation paradigm.Originality of the paper: Three network configurations of the opening of the innovation process within R&D networks are described in order to contribute to our knowledge on the transition from closed to open innovation in small and large firms.