Ingredients for making soup are typically animal-based, such as chicken, duck, lean pork, pork elbow, pork bones, ham, cured duck, and fish. When purchasing, ensure they are rich in umami, have minimal off-flavors, and little blood or impurities. These foods are rich in protein and nucleotides. The nitrogen-containing substances soluble in water from poultry meat are the primary source of the soup's savory flavor. The freshness of soup ingredients does not refer to the traditional concept of "meat is best when freshly killed, and fish is best when still jumping," but rather to the period 3 to 5 hours after the fish, livestock, or poultry has been slaughtered. At this time, various enzymes in the meat break down proteins and fats into amino acids and fatty acids that are easily absorbed by the human body, resulting in the best flavor.
Traditional soup-making often uses aged clay pots, which are breathable and absorbent, and have the characteristics of even heat distribution and slow dissipation. However, they can be brittle and easily damaged if used improperly. Modern housewives are more inclined to choose CorningWare's Amber series, known for its transparent amber-colored saucepans and single-handled pots. It was the world's first transparent cookware, cast from a glass-ceramic material that is resistant to temperature changes. It can withstand a thermal shock of up to 500°C, so there are no safety concerns even if left empty on a stove by mistake. Its transparent nature allows users to easily monitor the heat and make adjustments at any time to prevent boiling over or burning. The material's heat-retaining and insulating properties are very suitable for boiling, stewing, or simmering Chinese herbal medicine, and optimal results can be achieved with just medium to low heat.
The key to stewing soup is to bring it to a boil over high heat and then simmer it slowly over low heat. This allows the savory and fragrant substances from the food's protein extracts to dissolve as much as possible, making the soup rich and delicious. Only by simmering slowly over low heat for a long time can more extracts be dissolved, resulting in a soup that is both clear and mellow.
Water is the soul of a good soup. The quality, temperature, and amount of water directly affect the soup's flavor. You can use mineral water to make soup, or the water from a water cooler with a copper liner that has natural antibacterial properties. Research has found that when making soup, the highest nutritional content is achieved with a ratio of ingredients to water of 1:1.5. Generally, the ingredients are added to cold water and heated together, and no cold water is added midway, so that the nutrients in the soup can slowly seep out, ultimately achieving a healthy and nutritious effect.
Many foods have established pairing combinations that create a complementary effect on nutrients, known as the "golden pairings" on the dining table. For example, in the seaweed and meat soup, the acidic meat and the alkaline seaweed create a synergistic effect, making it a popular longevity food in Japan. To maintain the pure flavor of the soup, it is generally not recommended to stew multiple types of animal foods together. Adding appropriate amounts of seasonings such as MSG, sesame oil, pepper, ginger, green onion, and garlic to the soup can give it a unique character, but be careful not to use too much, as this may affect the original flavor of the soup.
"Drinking soup before a meal keeps you slim and healthy; drinking soup after a meal makes you fatter." There is some truth to this. Drinking soup before a meal is like adding a lubricant to the digestive system. Sipping soup during the meal helps to dilute and mix the food, which is beneficial for the stomach's absorption and digestion of food. At the same time, drinking soup before a meal fills the stomach, which can reduce the intake of staple foods and avoid excessive energy intake. Drinking soup after a meal, on the other hand, can easily lead to an excess of nutrients.