Abstract: For more than two decades there has been a growing niche for ethically sourced coffees, at the same time as a revitalisation and development of sourcing models focused on indicators of coffee quality and measures of taste. Small independent and multinational buyers and roasters have become progressively interested in sourcing coffee in a way that privileges sustainable and/or high quality indicators, and are increasingly engaged in debates about solidarity versus mainstreaming, quantity versus quality, and provider of caffeine versus taste. Research on one coffee producing country, Guatemala, suggests how these debates have affected the historical evolution of the coffee market. This ethnographic study traces the qualifications of Guatemalan coffee and argues that responses to both the enactment of the technologies, as well as the perceived limitations of sourcing models have produced new articulations of ethics and taste. Producers and small entrepreneurs located in Guatemala reconfigure the practices of cultivation, processing, and selling/buying in relation to circulating market indicators. They create locally situated attachments to the coffee through skill transfer and knowledge exchange and in this way they imitate and also transform international valuations of taste, ethics and quality. This thesis works to make visible the range and diversity of processes and agencies involved in the production of markets for ethical coffee and considers coffee as vital and mobile; an active producer of public effects rather than a passive object moved through a commodity network. This view enables a more open, relational and mobile account of both coffee and of ethics, one which is capable of making clear the important and emerging role of taste. This thesis extends the qualifications of coffee to the daily enactments of cultivation and the skills and techniques that work to reveal taste. On this view, taste mediates the agency of the materials in both high quality and sustainable coffees and this expands and extends ethics to interpersonal, material and bodily relations that link producers and consumers in multiple ways.