The 'Du Sud' cuvée takes its name from its geographical location at the southern border of Saône-et-Loire. The grapes come from a 1-hectare parcel planted in 2016 at the limit of the Clos des Rontets, perched on the hilltop south of the village of Fuissé, in the Mâcon-Village appellation but right at the edge of Pouilly-Fuissé. The soil structure is similar to that of the estate's historic Clos: hard limestone bedrock at 120-150 cm depth, a mid-layer of flat stones, and a superficial horizon of clay and silt 15 to 20 cm thick. The plot has a slight eastward-facing slope, surrounded on three sides by nearby forest that provides shade and coolness from the afternoon onwards, creating a significant temperature range that allows progressive ripening whilst preserving natural acidity.

Claire Gazeau and Fabio Montrasi farm the entire Château des Rontets vineyard under certified organic viticulture (Ecocert since 2005). Harvest is carried out manually in small crates to preserve berry integrity. Alcoholic fermentations take place exclusively with indigenous yeasts, in 228- and 400-litre barrels as well as 30-hectolitre foudres, without any addition of sugar, acid or enzymes. Ageing continues on lees, without bâtonnage, in vessels without new oak — the estate's philosophy being to reveal terroir without masking it with wood. Bottling is done without fining or filtration, after a final rest in stainless steel tanks allowing natural clarification.