According to many winemakers, over-cropping is the ultimate sin of grapegrowers. In France, the Cotes du Rhone trade association recently hired vineyard inspectors to check that grape yields didn't exceed the authorized limit of 2.5 tons per acre. The move is part of a crackdown to enforce the regulations governing Appellations d'Origine (AOCs). Where yields exceed the limit, the resulting wine may be downgraded to vin du pays.
Brommie remember 1 ha= 2.47 Acre thus in France they limit themselves to just over six tons per ha. In RSA where the climate is warmer you easily get good quality from 8 tons per one ha. Are you going to plant?
Are you running a profitability analysis of wine making vs trading - or is this just a hypathetical "Is it actually possible" study. I'm not a wine maker - I would still bet that yield is going to fluctuate annually based on rainfall, soil nutrition, staff issues, etc. And some years will probably give you better quality cab than others.
Saash: Mother nature will determine quatity and quality.With pruning,water ect. you can also manipulte quantity and quality.Profitabilty of wine making versus trading. Only thing I can say that at least you can drink for free at wine making.
In the Northern Cape under irrigation it is possible to get 8 ton per ha, highest was 14 tons /ha with Cabernet sauvignon. Colombard's (a white cultivar) yield is from 25 to 50 tons /ha under irrigation.
This might be hipothetical but I am considering the oppertunity to buy (I think it might be reasonably priced) 17 ha of which 9ha is existing Cabernet vineyard. The rest is described as "mixed grapes".