Effects of Bicarbonate Ions in Tea Brewing Water on Sensory Properties and Substances of Different Teas

This study investigated the effect of formula water based on soda water and HCO₃^- on the sensory evaluation and substances of different teas. Highly fermented teas showed better sensory quality with a higher soda water ratio in the formula, while low-fermented teas improved with a small amount of soda water. Low HCO₃^- (≤21.97 mg/L) enhanced aroma and reduced bitterness, whereas high HCO₃^- (≥40.27 mg/L) can dim the brightness of tea infusion, dull the aroma, and reduce refreshing taste. High HCO₃^- is unfavorable to green tea's substance stability but somewhat beneficial to that of black tea. When brewing tea with TBW (tea brewing water), a longer brewing time yields more substances dissolved by HCO₃^-. Compared to four waters, TBW was better for green and black teas. In short, multiple brews with TBW were best. This study provides a reference for the optimization of the quality of tea brewing water.