The concept of a circular economy has arisen in response to the problems related to the limits of the dominant linear economic system in contemporary societies and of the finite resources of our planet. The transition from waste status to a raw material by reusing it makes it possible to modify its value for future users and thus to redistribute this value. This article focuses on the case of spent grain to illustrate the role of the circular economy in food transition. Bases on a series of interviews, the paper discusses business modeling to operationalize sustainable development in the food sector and presents a discussion and conclusion on the advantages and limitations of the deployment of the circular economy in the brewing industry, taking into account and understanding the interests and constraints of various stakeholders.