-Research team @ 茶水部 LittoTea, 澄萃茶藝.
The purpose of the tea roast
There are two purposes of the tea roast, keep tea dry and improve the quality of tea. First, keeping tea dry and reducing tea moisture content below 5% help extend the retention period and maintain the good quality of tea[1-2].
The scent appears with the temperature increasing. The roast can activate amino acids, catechins, carbohydrate or pectin in tea to have chemical changes, which would help increase the scent and roasted aroma. The degree of the scent varies with the degree of the roast, fresh scent, ripe fruit scent, caramel aroma, and even a fire burning smell in order. Meanwhile, the roast can change the color of tea as well. Tea color mainly comes from chlorophyll. The emerald color turns to brown, red-brown, or even black-brown with the different degree of the roast[2-3].
Furthermore, the increase of polyphenols, theaflavins and thearubigins in the process of the roast makes tea color look yellow or red. The color becomes darker with the roasting increasing. Meanwhile, caffeine and tannic acid decrease a bit, which makes tea taste softer. The roast helps increase the scent. However, tea that has the floral scent can’t be processed with the roast. Otherwise, the scent would be damaged seriously[2-3].
The initiative purpose of the roast focus on the result that tea tastes softer and the scent appears. The temperature of the roast is not allowed too high, usually below 110 degrees Celsius. There is a risk of burning if the temperature is over 130 degrees Celsius. The fiber of tea and the quality of tea would be damaged as well if the roast time takes too long. Generally, it is believed that old tea takes more time to roast, and also need higher temperature to remove savor. In contrast, fresh tea takes fewer time to roast, and need lower temperature. Tea usually has a burning smell after the roast. The smell would subside a bit around after few days, and the quality of tea becomes stable after a week. It takes more time to make the quality of tea stable with the heavier degree of the roast[3-4]
The roast can remove savor, improve the scent and the taste of tea, and increase the quality. However, the degree of the roast doesn’t equal the better quality of tea. Tea may lose its original flavor with the roast increasing. Original tea is still good, right?
-Research team @茶水部 LittoTea, 澄萃茶藝.