To the north of Ampuis, on the Côte Brune, the parent rock consists of shale with proportions of dark and light mica, which give the soil its namesake dark brown colour. To the south, the slate contains gneiss and weathers with it to a lighter grey, to which the vineyards owe the name Côte Blonde.
The wines are correspondingly different: those from the north are generally more powerful and robust, those from the south more delicate, charming and supple - although there are of course also cuvées from both zones. The most charming wines, however, often owe their character to the addition of Viogner, i.e. white wine grapes, a maximum of 20% of which is permitted here. However, such a high proportion is rare, and especially in the Côte Brune, the wines usually consist entirely of Syrah. Other varieties are not permitted.