Of all the factors such as soil, climate, viticulture, and detailed winemaking techniques which have an effect on wine quality, vine variety is probably the easiest to detect in a blind tasting. The colour of the grapes’ skin determines what colour of wine can be produced: red wine can be produced only from dark-skinned grapes. Only grape varieties which ripen readily and/or are prone to noble rot are likely to produce good sweet wines, while only those with high levels of natural acidity are likely to produce good brandy or sparkling wines. But, even more important in identification, individual grape varieties tend to produce wines with identifiably different flavours. Indeed, in very general terms, it is a mark of quality in a vine variety that it is capable of producing wines with distinguished and distinctive flavours, even if those flavours are heavily influenced by weather, terroir and, vineyard practice. Lesser vine varieties tend to produce wines that are neutral and undistinguished, however promising the vineyard site.