紅茶水色に対する金属塩類および水の硬度の影響
1993 年 26 巻 3 号 p. 225-229
詳細
1993 年 26 巻 3 号 p. 225-229
The effects of metallic salts and the hardness of water on the color of black tea infusion were examined.
Water with the hardness of 70°-80° of calcium and the concentration of about 30 ppm of calcium ion produced the strongest redness. The addition of calcium ionmore than 60 ppm to the water caused the cream down.
Water with the hardness of magnesium more than 400°and the concentration of magnesium ion more than 97 ppm had an effect on the color of black tea infusion.
It is clarified that magnesium dose not practically affect the color of black tea infusion and from the sensory test, various factors such as the balance of redness and yellowness, value, chroma and transparency interact in the color of black tea infusion.
The soft water with the hardness lower than 75° and the concentration of calcium ion less than 25ppm, is preferable for producing the beautiful color of black tea infusion.
