Scaffolding is one of the critical features in a problem-based learning environment to address challenges associated with problem solving. While transfer of responsibility is considered as an ultimate goal in scaffolding that is adaptive and contingent, it is rarely studied and practiced. Thus, the purpose of this study was to inform a deeper understanding of one middle school teacher's manner of soft scaffolding, which refers to just-in-time and contingent support, through teacher-student interaction to examine how transfer of responsibility was achieved. We investigated one middle school teacher's forms of scaffolding during a problem of food systems and supply chains related multiple aspects of sustainability and social justice issues. Using conversation analysis, three discursive patterns in scaffolding emerged: (1) shifting patterns of turn-taking organization; (2) leaving room for the students to take responsibility by giving extended wait time; and (3) extending the discussion with different examples. The paper concludes with implications for PBL teachers and researchers.