Darjeeling tea is known for its warming properties. These warm thermal properties of second flush Darjeeling are due to a variety of factors. Most of the warmth develops as the green tea leaf is oxidized. Oxidization induces warm thermal energy. The once green, cool properties of the plucked leaf undergo a process where heat is generated as the leaf oxidizes. The result is a dry leaf that is dark often with a reddish tinge to them, a liquor that is red-brown, and wet leaves that are coppery brown. All of these colours contain the colour spectrum of a dark red. Red is the colour of summer. Early Summer, late spring is when these leaves are picked. As a result they contain in them the heat of summer. Red is the colour of the Heart, therefore this tea is especially good for preventing heart conditions (see here and here and here). Because these leaves grow slowly at such high altitudes often among the high misty mountain tops they generate more heat, more yang. These leaves also contain in them dark colours. Darker colours indicate depth, like the depth of space or that of a deep ocean. In this way the qi of Darjeeling second flush is warm and deep, qualities that are often sought to balance the cold depths of Winter, or simply when we feel cold.
The taste of Darjeeling Second Flush also is an indication of its qi. Hong cha is sometimes known for its rather bitter taste, especially when production dictates heavy oxidization. Bitter tastes are descending in nature and have a special relationship with heat in the body as it is often associated with the communicating transfer of heat from the upper (yang) parts of the body to the lower (yin) parts of the body and conversely from the lower parts of the body to the upper parts of the body. This is especially true with second flush as it contains both the colour red, warmth, and darker colours that represent depth. Bitter tastes also descend deep in the body.
However if it was a strong bitter taste, its properties would be too harsh and would simply have a draining effect on the body, thereby depleting our qi. This is not the case because there is balance between Taste and Smell. The deep bitter taste anchors the warm qi downward and the light smell of florals and fruits lift it up. There is good movement of energy, a communication between upper and lower imparting heat there.
The bitter descending taste is also moderated by a fruity, often muscatel, sweetness. Sweet tastes strengthen and ascend, remedying much of the harsher effects of the bitter taste while circulating the warm thermal energy.
Second flush Darjeeling is processed in a way that a large surface area of the leaf and the enzymes released in production are quickly exposed when steeped in hot water. The release of its energy is quick and often dramatic and powerful, usually resulting in fewer more powerful infusions.
The nature of Darjeeling second flush is such that Middle Way is therefore maintained as Yin (descending, deep, dark, more taste, and bitter) is masterfully balanced in the cup by Yang (ascending, light, red, floral odour, and sweetness). The balance and harmony of this tea along with its characteristic cha qi is why Darjeeling Second Flush is even prized by the teamasters of Asia, least those with an open mind.