Brettanomyces (Brett) is an awkward, a yeast subject to much debate in the wine world. Brett changes taste profiles, but not in any simple or stable way. In doing this, Brett is an active agent in the making of wine, the social construction of taste/quality and the social experience of wine drinking/expertise. This article draws on ongoing ethnographic and auto‐ethnographic research to argue that Brett's entanglement in social relations with humans is geographically and socially varied. Brett has different relations in natural wines for example. Coming to know Brett is therefore inherently relational, a sensorial and cultural experience as much as a matter of science.