The density of planting required is at least 4,500 vines per hectare. The distance between rows should be 2.50 metres at most, and the distance between individual vines within the row should be at least 0.85 metres. Pruning of vines should take place annually, before the first leaves have fully developed. Single and Double Guyot, Cordon de Royat (unilateral cordon), Eventail (Fan) and Gobelet (Goblet) are the permitted pruning methods. The number of buds (that will eventually bear clusters) is limited to a maximum of 12. Once suckering and green harvesting have been completed, the maximum number of clusters allowed per vine is 14. Plots that have been abandoned can no longer be considered part of the AOC area. Wine-growers must mow or use herbicides to prevent weeds from growing up around the vines, otherwise they could create a humid micro-climate below the leaves that would encourage the development of cryptogamic diseases. They must also carry out treatments to keep the occurrence of diseases such as
mildew and
oidium below the permitted quality thresholds. The proportion of dead or missing vines may not exceed 20% of the total number. If this percentage is exceeded, the final yield must be cut down proportionately.
Harvesting Harvesting is carried out when the grapes are fully ripe. The degree of ripeness is ascertained by the presence of noble rot or signs of over-maturity, i.e. grapes have begun to dry out on the vine and have become shrivelled, golden-coloured berries. It can also be assessed by measuring the sugar content. Before harvesting can begin, it must be shown that the grapes contain at least 255 grams of sugar per litre. Harvesting is carried out manually over multiple successive pickings, combined with sorting of the grapes. The grape-pickers are ordered to pick only those clusters or part-clusters which are either fully ripe or have heightened sugar content brought about by noble rot. This automatically precludes the use of harvesting machines. ==Winemaking==