Abstract: This study aimed to clarify the effects of different water qualities on the flavor profile of raw and ripe Pu-erh tea from Jingmai Mountain. Eight typical water samples were used to brew the tea, and methods such as an electronic nose, electronic tongue, sensory evaluation, and color difference analysis were employed to systematically compare the aroma, taste, color, and physicochemical composition of the resulting tea infusions. The electronic nose results showed that the raw Pu-erh tea infusions brewed with BSS and NFSQ had the most distinct aroma profiles among the eight water types, mainly perceived by sensors W1W, W1S and W5S, and the aroma profiles were correlated with water mineralization and ionic strength; the tea infusion brewed with QCS was clustered close to multiple sensors, exhibiting a diverse aroma profile. The ripe Pu-erh tea infusions made with BSS and PESQ were separated most clearly from other samples, their aromas were mainly associated with the response of sensors W1W, W2W, and W2S and were correlated with changes in anion contents of brewing water. The QCS and NFSQ samples were clustered near the origin, indicating more balanced aroma composition. The tea infusions brewed with low-mineral soft and natural water such as QCS and NFSQ yielded higher sensory scores, with mellow taste, balanced aroma and bright color. In contrast, the tea infusion brewed with high-hardness tap water exhibited increased bitterness and astringency and darker color. Color analysis showed that high-hardness water decreased the brightness value of tea infusions and increased the redness and yellowness values, thereby enhancing the reddish-yellow hue. Higher Ca2+ and total dissolved solids levels were associated with restricted aroma release and increased extraction of tea polyphenols and caffeine, leading to enhanced bitterness and astringency. Low-mineral soft water promoted the extraction of volatile and taste-active compounds and enhanced the freshness and sweetness as well as overall flavor. Overall, raw Pu-erh tea is more sensitive to brewing water quality, with its infusions exhibiting greater changes in flavor and color compared with ripe Pu-erh tea. Low-mineral soft water (such as QCS and NFSQ) is suitable for brewing both raw and ripe Pu-erh tea from Jingmai Mountain, producing infusions with well-balanced aroma, taste and color, whereas high-hardness water results in poor infusion quality. These findings highlight that brewing water plays a decisive role in the quality of Pu-erh tea infusion, providing a scientific basis for the selection of suitable brewing water for Pu-erh tea. This study recommends using soft or softened water for brewing Pu-erh tea to fully highlight its flavor characteristics.

Key words: Pu-erh tea; Jingmai Mountain; brewing water quality; flavor compounds; electronic nose; electronic tongue; sensory quality; physicochemical properties