Pasteur and the entry of wine into scientific modernity Among the imposing bulk of Louis Pasteur’s work, his Studies on Wine are the least known and commented. However, in these Studies, collected in 1874, he displayed all the facets of his versatile genius, as a citizen, as a teacher, and as a scientist. As a chemist, he analyzed the steps of vinification and the mechanisms of fermentation. As a citizen, he aimed at the improvement of an industry key to the French prosperity. He was also a man rooted in his terroir; aware of the know-how of wine makers, and a teacher working hard with his students. This article explores the circumstances and results of his work and assesses the so- called pasteurization of wine, that, contrary to the epic narrative, was not later established for wine, as it was for other natural beverages. Lastly, the article raises the question of the role of the Studies on Wine on the emergence of the Pasteurian microbial theory of human illnesses.