In this paper we focus on classroom interaction between teacher and students in desk interactions, and on how attitudes towards knowing and learning are demonstrated in so called epistemic stances. The aim is to explore how the teacher’s epistemic stance changes through a series of desk interactions with different students and how this can be understood as learning in a situated activity. The analysis is grounded in empirical data consisting of video recordings where one teacher assists five different groups of students with the same question during a geography lesson. In the analysis we highlight how the teacher orients to the learning activity, and how his participation in this activity changes in the situationally unfolding contingency of interaction. In the studied example, the construal of a list with three examples becomes an interactional resource for the organization of both participation and content. Through changes in epistemic stance, a learning trajectory evolves as the teacher tries out a routine. These subsequent changes can be understood as professional learning in on-going teaching. In the studied classroom, the main feature of this learning can be described as routinization.