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Iced tea is a form of cold tea. Though it is usually served in a glass with ice, it can refer to any tea that has been chilled or cooled. It may be sweetened with sugar or syrup. Iced tea is also a popular packaged drink that can be mixed with flavored syrup such as lemon, raspberry, lime, passion fruit, peach, orange, strawberry, and cherry. While most iced teas get their flavor from tea leaves (Camellia sinensis), herbal teas are sometimes served cold and referred to as iced tea. Iced tea is sometimes made by a particularly long steeping of tea leaves at a lower temperature (one hour in the sun versus five minutes at 80 to 100 °C (176 to 212 °F), which is known as sun tea. Although it is not a traditional way to serve tea, iced tea gained widespread popularity during the late 1980s, even in rural areas. Many varieties of tea, including green tea, are available canned or bottled and are sold in stores. Many families make iced tea either by putting a large amount of ice in a small amount of strong hot tea or by putting hot tea in a fridge for some time. Common types of iced tea are black, green, and oolong (烏龍茶), as well as many herbal varieties. Iced herbal teas are especially popular in the hot summers, where "yin"（陰）or cooling herbs are used to make tea such as chrysanthemum and kuding tea (苦丁茶). Cooled (but still warm) tea was popular throughout ancient times. Refrigerated tea was previously only available to those politically connected to the Communist Party. The introduction of limited capitalism and free-market reforms starting in 1978 made refrigeration available to the general population for the first time. China's refrigerator-ownership increased from just 7% of urban families in 1977 to 95% in 2009.

Source: Wikipedia