Comparative Analysis of Phenolic Accumulation Throughout Maturation in Five New White Wine Grape Varieties Under Temperate Monsoon Climate Conditions in Yantai

While phenolics determine wine’s sensory and functional properties, white grape varieties remain less studied than red grape varieties in terms of phenolic profiling. Five white grape varieties and Chardonnay (control) were analyzed from veraison to bottling for phenolics and physicochemical properties to identify suitable cultivars for temperate monsoon climate conditions. The berries of M1 had a relatively low sugar content (181.6–192.3 g/L in 2022; 160.1–165.4 g/L in 2023), making them suitable for the production of low‐alcohol wine. The berries of L1 and R3 showed the most desirable sugar‐to‐acid balance (29.85–33.86 in L1; 30.38–34.96 in R3) for winemaking in 2022, while Chardonnay (CK) exhibited the optimal ratio (31.13–33.27) in 2023. The wine made from R3 was characterized by high acidity. During the 2 years, phenolic content in the skins of all six varieties generally decreased during their growth and development, reaching the lowest value at harvest time. The content of phenolic substances in the berries and wines of L1 was significantly higher than that of other varieties. R2 berries contained the highest resveratrol content (> 95 μg/g, DW) among all cultivars. R1 berries contained a relatively high content of kaempferol (> 34 μg/g, DW). The specific enrichment of these monomeric phenols marks varietal differences in antioxidant capacity and reveals inherent photoprotection mechanisms, which provides a foundation for targeted breeding and healthy wine development. Taken together, the new white grape varieties exhibited distinct phenolic profiles and physicochemical characteristics, expanding viticultural options for Yantai and similar regions.