Cluster and berry selection is widely accepted as an important process before fermentation for the production of premium-quality wine. However, little is known about the quality variation of the berries within and between different clusters. In the present study, four clusters of ‘Cabernet Sauvignon’ (Vitis vinifera L. cv.) grapes with different size and compactness were analyzed at normal harvest date. Each cluster was assessed for compactness, weight, berry number, and each berry was assessed for seed weight and count, seed color, soluble solid concentration (SSC) and skin color. Based on this survey, the cluster and berry selection was simulated. Correlating the data with the light exposure of the berries failed to give useful correlations with SSC, but showed that skin pigmentation was significantly affected. Additionally, cluster compactness markedly impacted on the berry pigmentation and seed maturation. There was a weak correlation between the SSC of each berry and the berry’s weight, showing a slight decline with increasing weight. Cluster and berry examination could evaluate the proportion of the medium size berries (0.76–1.50 g) and reduce the proportion of one-seeded berries thereby, increasing the seed weight per unit of berry weight. This also reduced the coefficient of the variation (CV) of the berry weight, which had virtually no influence on the mean and standard deviation of the SSC for the whole berry population. Therefore, the potential quality of grape clusters for winemaking was a function of cluster compactness, berry size and extent of seed maturation. In order to make the premium-quality wine, initially clusters should be selected to eliminate those that are very tight, and then select berries on the basis of berry sizes.