The ancients were very particular about the temperature of tea. Cai Xiang, a Song Dynasty poet, said in the Book of Tea: "It is the most difficult to wait for soup (that is, to cook soup and tea-the author's note). Unfamiliar words will foam and float; If it is overcooked, it will sink the tea. It used to be called crab eyes, and the soup was overcooked. Cooking with a sink bottle is hard to tell, and waiting for soup is the most difficult. " Xu Cishu in the Ming Dynasty put it more specifically in Tea Sparse: "When water enters the pot, it needs to be boiled urgently. When there is a loose sound, the lid should be uncovered to show that it is old and tender. After the crab eyes pass, the water is slightly turbulent, which is too late; The big waves boil and turn to silence, which is out of place; If the soup is too old, it will never be used. " As mentioned above, when making tea and boiling water, you must have a big fire, not a slow fire. It is advisable to just boil and foam. Make tea with this water, and the tea soup is delicious. If the water is boiled for too long, it is what the ancients called "old water". At this time, the carbon dioxide dissolved in water is evaporated, and the fresh and refreshing feeling of tea is greatly inferior. The boiled water was called "tender" by the ancients and was not suitable for making tea. Because of the low water temperature, the effective components in tea are not easy to leach, which makes the fragrance low and light, and the tea leaves float on the water, which is inconvenient to drink. The control of tea temperature mainly depends on what kind of tea to drink. High-grade green tea, especially all kinds of famous tea with delicate buds and leaves (famous tea), cannot be brewed with boiling water at 100℃, and it is generally appropriate to brew at about 80℃. The more tender and greener the tea leaves are, the lower the brewing water temperature will be, so that the tea soup will be light green and bright, the taste will be fresh and refreshing, and the vitamin C in the tea will be less damaged. At high temperature, tea soup is easy to turn yellow, bitter in taste (caffeine in tea is easy to leach out), and vitamin C is destroyed a lot. As usual, the high water temperature will "burn" the tea. All kinds of scented tea, black tea and low-grade green tea should be brewed with boiling water at 100℃. If the water temperature is low and the permeability is poor, the effective components in tea will be less leached and the tea taste will be light. Oolong tea, Pu 'er tea and scented tea are all brewed with boiling water at 100℃, because the amount of tea used is large and the tea leaves are very old. Sometimes in order to maintain and improve the water temperature, it is necessary to heat the tea set with boiling water before brewing, and pour the boiling water out of the pot after brewing. Ethnic minorities need higher water temperature to drink brick tea. Break the brick tea and put it in a pot to boil. Generally speaking, the water temperature of making tea is positively correlated with the solubility of effective substances in tea. The higher the water temperature, the greater the solubility and the stronger the tea soup. On the contrary, the lower the water temperature, the smaller the solubility and the lighter the tea soup. Generally, the leaching amount of warm water at 60℃ is only 45-65% of that of boiling water at 100℃. It must be explained here that, as mentioned above, high-grade green tea is suitable for brewing with water at 80℃, which usually means that water is boiled (the water temperature reaches 100℃) and then cooled to the required temperature; If it is raw water without bacteria, it only needs to be burned to the required temperature. People in China have always liked tea. Everyone seems to know how to make tea, but not everyone can make tea well. Good tea also needs good water. The standard of good water is judged from five aspects: water quality: clear, lively and light, and water taste: bitter. According to modern scientific analysis, ionized calcium containing more than 8 mg of magnesium per liter of water is called hard water, and vice versa. Soft water makes tea color, aroma and taste good, while hard water makes tea easy to change color, which will greatly affect color, aroma and taste. The weight of water also includes the number of mineral components contained in water, as well as acidity and alkalinity. When you make tea with water containing more iron and alkaline substances, the tea soup will float with a layer of "rust oil" and be turbid and precipitated. When the acidity of water is high, the tea color will become dark or even black. Therefore, it is suggested to make tea with soft water (such as natural mineral water of Kunlun Mountain in Qinghai, Bali Natural Mineral Water of Taihang Mountain in Henan and Laoshan Natural Mineral Water in Qingdao). At present, tap water is usually used to boil tea. If possible, let the tap water stand for about 20 hours, and it is better to use it after the disinfection smell in the water volatilizes. If the water quality is not good, you can cook for a period of time to precipitate impurities and eliminate odor. Pure water is good for making tea, and pollution-free natural mineral water is also good. It is also good for making tea away from densely populated rivers, lakes and seas. Snow water and rain water, which were highly praised by the ancients, are not good water in most areas because of pollution. There are many descriptions about the relationship among tea, water and utensils in China ancient books. For example, Amin Xu Cishu said in Tea Sparse that good tea is fragrant and made of water. Without water, tea is impossible. It is also said that tea must be born in water, and eight-point tea meets very water, and tea is also very good; Eight servings of water, try ten servings of tea and eight servings of tea. Lu Yu's drinking principles in The Book of Tea are: above mountains and rivers, within rivers, under wells, above gravel milk springs, above Ikenoe, and above flowers. The ancients also summed up the best combination of tea and water, such as "Longjing tea, tiger running water", "water in the heart of the Yangtze River, tea at the top of Mengshan Mountain" (1). Most mountain springs come from Shan Ye where rocks overlap. The mountain is lush with vegetation, and the mountain spring gathered from the trickle of rock faults is rich in carbon dioxide and various trace elements beneficial to human body; The spring water filtered by sand and gravel is clean and clear, and contains almost no chlorine, iron and other compounds. Using this spring water to make tea can keep the color, fragrance and shape of tea to the maximum extent. But not all mountain springs can be used to make tea, such as sulfur mineral water. On the other hand, mountain spring water is not available everywhere, so for most tea drinkers, they can only choose suitable tea products according to conditions and possibilities. (2) Rivers and lakes belong to surface water, containing more impurities and higher turbidity. Generally speaking, it is difficult to achieve good results in making tea. However, they are far away from human habitation, with lush vegetation and less pollutants. Such rivers and lakes are still good water for making tea. For example, Fuchun River in Tonglu, Zhejiang, Qiandao Lake in Chun 'an and Jianhu Lake in Shaoxing are all examples. In the Tang Dynasty, Lu Yu said in the Book of Tea: "Its rivers take away those who are far away." That's what I'm saying. Bai Juyi in the Tang Dynasty said in his poem: "The water in Shu was surprised when it arrived, and the water in Wei was precious when it was first fried." He thinks Wei Shui fried tea is very good. In the Tang Dynasty, Li Qunyu said, "Wu Ou is fragrant with water and green flowers", and it is not bad to make tea with water. Xu Cishu in the Ming Dynasty further said in Tea Sparse: "The water of the Yellow River falls from the sky. Turbid soil, clear and clean, fragrant and spontaneous. " It is said that even the turbid Yellow River water can make tea soup mellow as long as it is clarified. This situation is the same in ancient times and modern times. (3) Snow water and falling water were called "Tian Quan" by the ancients, especially snow water, which was highly respected by the ancients. Bai Juyi's Sweeping Snow and Cooking Sweet Tea in Tang Dynasty, Xin Qiji's Writing Tea Classics and Cooking Tea Snow in Song Dynasty, Xie Zongke's Sweeping Cold Night and Cooking Green Dust in Yuan Dynasty, and Cao Xueqin's Sweeping Snow and Cooking Fresh Snow and Timely Tea in Qing Dynasty all praised making tea with snow water. As for rain, generally speaking, it varies from time to time: autumn rain, the sky is crisp, there is almost no dust in the air, and the water is "cool", which is the top grade of rain; Meiyu, the weather is dull and rainy, and the water tastes "sweet and slippery" and inferior; In summer, it rains, thunderstorms, flying sand and stones, the taste of water is "out of shape" and the water quality is not clean. But whether it is snow water or rain water, as long as the air is not polluted, it is always cleaner than rivers, lakes and seas, and it is a good water for making tea. Unfortunately, in modern times, many areas, especially industrial areas, were polluted by industrial smoke and odor, which made snow water and falling water worse and deformed. (4) Well water belongs to groundwater, with low suspended solids content and high transparency. However, most of them are shallow groundwater, especially urban well water, which is easily polluted by the surrounding environment and is harmful to the taste of tea. So, if you can draw water from the well of life to make tea, you can also make a good cup of tea. That's what Lu Yu said in the Tea Classic in the Tang Dynasty, and Lu Shusheng said in the Seven Kinds of Fried Tea in the Ming Dynasty, "There are many people who take wells and many people who draw water." Jiao Hong's Yutang Yu Cong in the Ming Dynasty, and Dou Guangnai and Zhu Jun's Wen Kao in the Qing Dynasty all mentioned Dongdong Well in Jinghua Temple, which was once the drinking water source of the imperial palaces in the Ming and Qing Dynasties. Guanyin well in Nan 'an, Fujian, used to be the water of tea fighting in Song Dynasty, and it still exists today. 5] Tap water contains chlorine for disinfection, etc. If it stays in the water pipe for a long time, it also contains more iron. When the content of iron ion in water exceeds five ten thousandths, the tea soup will be brown, and chloride will react with polyphenols in tea, forming a layer of "rust oil" on the surface of tea soup, which tastes bitter. Therefore, it is best to use tap water to make tea in a pollution-free container, store it for one day first, then boil it after releasing chlorine gas, or purify the water with a water purifier, so as to become a better water for making tea. (6) With the progress of modern pure water science, using multi-layer filtration, ultrafiltration and reverse osmosis technology, ordinary drinking water can be turned into pure water without any impurities, and the pH value of water can be neutral. Making tea with this kind of water is not only because of its good clarity and high transparency, but also because of its pure aroma and taste, fresh and refreshing. There are many brands of pure water on the market, most of which are suitable for making tea. Besides pure water, mineral water with good quality is also good water for making tea.