Résumé : Echoing a transformative perspective of agroecological transitions, alternative breadsupply chains (ABSCs) experiment with technical and social innovations to overcome the limitationsof industrial baking through artisanal knowledge. Yet, ABSCs in Wallonia, Belgium, face specificchallenges as the heritage wheat varieties they use, while adapted to local conditions, do not meetindustry-defined "baking value" standards and are thus deemed unsuitable for bread-making. This studydemonstrates that artisanal bakers can effectively use these flours, challenging traditional notions offlour “quality” in terms of nutrition and flavor versus workability. In this study, nine types of flour wereanalyzed using measures from industrial standards: protein content, water content, α-amylase activity,and baking strength. These flours were sourced from six heritage wheat varieties, two variety mixes(one field-based, one post-harvest), and one modern variety bred for organic agriculture, all grown onthe same field and milled under the same conditions. These varieties are used by farmers in WalloniaABSCs, showing their relevance to the local conditions. Their poor industrial ratings were then put tothe test by three artisanal bakers, who baked and assessed each flour using sensory-based evaluationtables before, during, and after baking. Semi-structured interviews provided insight into bakers'strategies for handling these flours and went further in the understanding of why artisanal bakers couldeven prefer allegedly unsuitable flours from heritage varieties than standard flours, easier to bake.Findings reveal that ABSCs bakers employ complex craft techniques, drawing on sensory awarenessand intuitive adaptation to address the variability of heritage flours. This artisanal perspective - viewingraw materials as “living matter” - and its set of related skills should thus be promoted in apprenticeshipas they are seen essential for a wider agroecological transition of food systems. These practicescontributing to processes of scaling deep sustainability initiatives, that aim to reshape values andnarratives of the broader system. Such perspectives would indeed contribute to reshaping values andnarratives, a dynamic that is crucial to support for amplifying the broader transformative potential ofABSC.