Our examination was carried out in the 103 ha apple orchard of the Kasz-Coop Ltd.. The plantation works with modern varieties standing on M9 root stock, planted in a tree density of 2500 tree/ha and treated with professional integrated technology. The date of harvest is defined by a combination of several ripening analyses methods. The orchard has its own ULO-system warehouse. Used in the experiment were four apple varieties: ’Idared’, ’Golden Reinders’, ’Jonagold’ and ’Braeburn’. While under ULO-storage, we took 20-25 piece samples 6 times regarding the four varieties, from which 5-5 pieces were kept under three weeks’ shelf life, measured on a weekly bases. In our research, we analysed the dynamics of the flesh firmness and the refractometric value under ULO-storage and three weeks’ shelf life, and the standard deviation dynamics of the refractometric value under ULO-storage. Analyses were based on the following measurements: flesh firmness, refractometric value and number of mature seeds. We looked for morphological and morphological-quality correlations. Through these we described the dynamics of the flesh firmness and the refractometric value under ULO-storage and three weeks’ shelf life for each variety. We referred to the stability of these attributes and to the dynamics of their change. Later, with the help of these, and also considering our practical experience related to the measurements, we characterised the four varieties. We found a positive correlation between the seed number and the flesh firmness in the case of the ‘Idared’, ‘Jonagold’ and ‘Braeburn’ varieties, but no correlation was found in the case of ‘Golden Reinders’ in this concern. We visualized the standard deviation dynamics of the refractometric values under ULO-storage. This allowed us to categorise the varieties.