A growing body of research and analysis identifies that fair trade practices create opportunities for developing world producers in a manner best described as providing ‘shaped advantage’, as access to Northern markets is reconfigured to operate under preferable conditions for some producers, but is not necessarily universally expanded and improved. From this point of view, impact potential is first and foremost delineated through the conditions of access to fair trade supply networks. In order to unpack this perspective, the article analyses barriers to entry embedded in the most significant avenue through which producers become involved in fair trade: certification by Fairtrade International. Here it is found that in addition to arguably justifiable restrictions on participation, structured around producer capacity to viably engage in trade, more arbitrary geographical restrictions embedded in the Fairtrade system are also an ongoing and significant barrier to widening impact. This article illustrates the reality of these technical limitations by presenting the mixed experiences of the National Smallholder Farmers' Association of Malawi, and their efforts to use Fairtrade certification as a market development tool.