I. The Roots of the “Four Natures” Classification for Foods and Tea

In the wisdom of Traditional Chinese Medicine (TCM), foods are categorized into cold, cool, warm, and hot “four natures.” Tea, as one of many foods, follows this classification system, which is deeply grounded in its effects on the body and the inherent properties of the food itself.

Just as certain foods suitable for those with a hot constitution or condition are classified as cool or cold, such as watermelon, which can effectively alleviate symptoms like fever, thirst, and irritability. Similarly, pears can help with coughing, chest pain, and excessive phlegm, and are also considered to be of a cold nature. This categorization is based on how these foods regulate symptoms, with cool or cold foods helping to mitigate hot conditions and restore thermal balance within the body.

Warm or hot foods, on the other hand, have properties opposite to cool or cold foods. Foods that are good for regulating cold constitutions and conditions are classified as warm or hot. For example, ginger, scallions, and coriander can effectively treat symptoms such as colds, fever, chills, runny nose, and headaches. They are of a warm nature. When someone has abdominal pain, vomiting, or a preference for hot drinks, dry ginger and Black Tea can provide warmth and relief. Spicy foods and alcohol can improve symptoms like cold limbs, aversion to cold, and rheumatic joint pain, and they are also of a warm nature. This classification provides important guidance for understanding the properties of foods and selecting appropriate ones based on one's physical condition.

II. Distinguishing Cold from Hot Foods

(a) The Mystery of Taste

From the perspective of taste, sweet and pungent foods, such as garlic and pomegranates, which receive more sunlight, are hot in nature. These foods absorb a lot of solar energy during their growth, and the sweetness and pungency in their taste are related to their hot properties. Foods that are bitter or sour, such as bitter melon, bitter greens, taro, plums, and papaya, tend to be cold. The bitterness and sourness in these foods are often associated with certain chemical components that give them a cold nature, reflecting the subtle relationship between food properties and their growing environment.

(b) The Hint of Color

From the color perspective, green plants, which grow close to the ground and absorb moisture, tend to be cold in nature, such as mung beans and green vegetables. They grow near the ground and are easily influenced by the moisture in the soil, which gives them a cold nature. Red-colored plants, such as chili peppers, black pepper, dates, and pomegranates, although they grow close to the ground, their fruits can absorb a lot of sunlight, so they tend to be hot. The red color often symbolizes warmth and vitality, and these plant fruits absorb ample sunlight, giving them hot properties, reflecting the influence of light on plant properties in nature.

(c) The Influence of Growing Environment

From the growing environment perspective, aquatic plants tend to be cold, such as lotus roots, seaweed, and laver. The characteristics of an aquatic environment make these plants cold in nature. Some land-grown foods, such as peanuts, potatoes, yams, and ginger, which are buried in the soil for a long time, are heat-resistant and contain less water, so they are hot in nature. The differences in land-based growing environments and the adaptation mechanisms of plants lead to their different properties, providing clues for distinguishing between cold and hot foods.

(d) The Association with Geographic Location

From the geographic location perspective, foods that grow in shaded, north-facing areas absorb more moisture and see little sunlight, so they tend to be cold, such as mushrooms and wood ear fungus. Their geographic location determines the amount of sunlight they receive and the moisture content, resulting in a cold nature. Foods that grow high up or in southeast-facing locations, such as sunflowers and chestnuts, receive ample light and heat, so they tend to be hot. Different geographic locations result in varying amounts of sunlight and heat absorption, leading to differences in the cold and hot properties of foods.

(e) Factors Related to Growing Season

The cold or hot nature of foods is also related to the growing season. Foods that grow in winter, when there is heavy cold, tend to be cold, such as Chinese cabbage, shiitake mushrooms, white radishes, and winter melons. The cold climate of winter gives these foods a cold nature. Foods that grow in summer, receiving abundant rain, tend to be cold, such as watermelon, cucumber, pear, and pomelo. The rainy and warmer environment of summer influences the nature of these foods, making them cold. By understanding the relationship between the growing season and the cold and hot nature of foods, we can gain a more comprehensive understanding of their properties.

III. The Categorization and Characteristics of Tea Based on Cold and Hot Properties

(a) Cool Teas

Green Tea and Tie Guan Yin Oolong Tea, due to their low fermentation degree, are considered cool teas. Green tea is loved for its fresh taste and rich nutritional content. Its simple production process retains more natural components, which makes it cool in nature. Tie Guan Yin, a type of Oolong tea, also has a relatively low fermentation degree and exhibits cool properties. Cool teas are suitable for people with a relatively hot constitution, helping to clear heat and reduce internal fire, alleviating the feeling of heat in the body.

(b) Warm Teas

Pu'er tea is a warm tea. Pu'er tea has unique flavors and benefits. It undergoes a certain fermentation process, which changes the composition of the tea leaves, giving it warm properties. Warm Pu'er tea is beneficial for the digestive system and is suitable for people with a relatively cold stomach. It provides warmth and helps with digestion and absorption.

(c) Hot Teas

Black tea, being fully fermented, is stimulating but mild and hot in nature. Dark teas (such as Fu brick and Liu Bao tea) are post-fermented fully fermented teas and are also hot in nature. Black tea and dark teas undergo full fermentation, significantly altering the composition of the tea leaves and producing beneficial substances while also giving them hot properties. These hot teas are suitable for people with a cold constitution, helping to dispel cold and keep warm, enhancing the body's resistance.

IV. Selecting Suitable Teas Based on Physical Characteristics

(a) Choices for Hot Constitutions

For those who smoke, drink alcohol, and are prone to internal heat and obesity, belonging to a hot constitution, it is recommended to drink cool teas. For such individuals, cool green tea and Tie Guan Yin can effectively alleviate symptoms of internal heat and clear the heat. Smoking and drinking can cause heat in the body, and cool teas can help regulate the body's balance, reducing the symptoms of internal heat. Additionally, they may also help with weight control.

(b) Choices for Cold Constitutions

For those with a weak stomach and intestines, who feel bloated after eating watermelon, this indicates a weak and cold constitution. It is recommended to drink neutral or warm teas. For those with a cold stomach and intestines, warm Pu'er tea or neutral teas are more suitable. These teas can warm the stomach and intestines, promote digestion, and alleviate symptoms like bloating. Neutral and warm teas are relatively mild and do not stimulate a cold stomach and intestines, helping to protect digestive health.

(c) Choices for Seniors

For seniors, it is recommended to drink black tea or Pu'er tea. As seniors' physical functions gradually decline and their digestive systems become weaker, the warm and hot properties of black tea and Pu'er tea can nourish their bodies. The fully fermented process of black tea makes it less stimulating and suitable for seniors. Pu'er tea can help with digestion and absorption, enhancing the body's resistance and improving quality of life.

(d) Choices for Urban Syndrome Sufferers

For those suffering from sub-health conditions common in urban environments, it is recommended to drink Dahongpao, black tea, and Pu'er tea, especially during the autumn and winter seasons. Urban syndrome sufferers often face