In recent years, the significance of small talk in institutional context has been receiving considerable attention in the field of sociolinguistics and communication studies. While scholars seem to agree on its social functions that facilitate the accomplishment of the institutional goal of the encounter by “oiling interpersonal wheels”, the wide range of interpersonal relationships enacted in small talk in institutional encounter has not been subject to rigorous research attention yet. By applying Conversation Analysis (CA), this study compares small talk in an on-campus coffee shop within two different interpersonal relationship groups: new customer-barista and regular customer-barista. Data were drawn from 35 video recordings of service encounters interaction involving both native and non-native English-speaking customers at a college-sponsored café. The findings show that small talk with a new customer strictly adhered to coffee-related topics and tended to be quickly curtailed by one or both interlocutors, as suggested by the alignment of their institutional roles of barista-customer. In contrast, small talk between a regular customer and a barista consisted of exchanges on a wide variety of topics. This finding suggests that the topic of conversation is a potential indicator of relationship through a shift of alignment to the interactional roles of ‘friend-friend’.