What are the factors that could affect the quality of cherries?

• Maturity. Fruit maturity is one of the key factors determining overall fruit quality. Cherries should be harvested at the end of the maturation stage when they are fully ripe to ensure good eating quality. Although the harvest timing varies based on the cherry cultivars, there is a harvest window of less than 5 days for harvesting fruit of optimal quality. The harvest season for cherries is short and labor-intensive. The ripe fruit is prone to mechanical damage, and cooling directly after harvest is important.
• Color, firmness, and water loss. Cherry fruit quality traits related to consumer purchase decisions are based on external quality attributes such as color, fruit size, stem freshness, absence of defects, and stem length. Aroma, flavor, sourness, sweetness, and texture are also essential attributes. Fruit color is, however, the main quality trait. Color development has been studied as a function of cultivar, ripeness stage, and storage conditions. In general, consumers prefer cherries fully ripe based on their dark skin color.
• Taste. Cherry fruit taste attributes, sweetness, and sourness are important for consumer acceptance. Sweetness can be expressed as soluble solids content, sourness as titratable acidity.

Source: 

Factors Affecting Quality and Health Promoting Compounds during Growth and Postharvest Life of Sweet Cherry (Prunus avium L.)