There are generally two types of thickening. One is a mixture of starch sauce and seasonings, commonly known as "pairing sauce," and is often used for dishes cooked with high heat and quick methods such as stir-frying and quick-frying. The other is a simple starch sauce, also called "wet starch," and is often used for general stir-fries. Pouring sauce is also a form of thickening, also known as thin glaze or琉璃芡 (liuli芡), and is often used for simmered, braised, and stewed dishes as well as soups. Depending on the cooking method and the characteristics of the dish, there are roughly the following several ways to use thickening sauces.
1. Coating Glaze: Generally used for dishes cooked by stir-frying. The starch paste is the thickest, with the purpose of completely coating the ingredients. For example, dishes like Yuxiang Rou Si (Fish-flavored Shredded Pork) and Chao Yao Hua (Stir-fried Pork Kidney) use this method, leaving almost no sauce in the plate after the dish is finished.
2. Thickening Glaze: Generally used for dishes cooked by methods such as stir-frying with gravy, quick-frying, braising, and stewing. The starch paste is thinner than the coating glaze. Its purpose is to thicken the dish's sauce into a paste-like consistency, achieving a fusion of the sauce and the dish with a smooth and tender texture, such as in Sweet and Sour Spare Ribs.
3. Flowing Glaze: The starch paste is relatively thin and is generally used for large or whole dishes. Its function is to enhance the flavor and sheen of the dish. Typically, after the dish is plated, the remaining sauce in the wok is heated and thickened, then poured over the dish. Part of it sticks to the food, and part remains in a glossy state, with some sauce left in the plate after eating.
4. Broth Glaze: This is the thinnest type of sauce, also known as thin glaze. It is generally used for stewed and braised dishes, such as Mala Tofu (Spicy Tofu) and Shrimp with Crispy Rice. The purpose is to slightly thicken the dish's sauce to achieve the requirements of rich color and fresh flavor.
To thicken a sauce well, several key points must be mastered:
1. Master the timing of thickening. It should generally be done when the dish is about 90% cooked. Thickening too early will cause the sauce to scorch, while thickening too late will cause the dish to be heated for too long, losing its crisp and tender texture.
2. The dish to be thickened should not have too much oil. Otherwise, the sauce will not adhere well to the ingredients, failing to achieve the goal of enhancing flavor and improving appearance.
3. The amount of sauce in the dish should be appropriate. Too much or too little sauce will result in the thickening being too thin or too thick, thereby affecting the quality of the dish.
4. When using a simple starch paste for thickening, the flavor and color of the dish must be adjusted first before pouring in the wet starch to thicken. This ensures the dish is flavorful and beautifully colored.
Starch is highly hygroscopic and can absorb odors, so attention should be paid to its storage. It should be protected from moisture, mold, and odors. The ideal conditions are room temperature at 15°C and humidity below 70%.
In cooking, there is also the requirement of "bright oil glaze." This means that after the dish is cooked and the sauce is thickened, various flavored oils are drizzled in, allowing them to blend into the glaze or adhere to its surface. This serves to enhance aroma, brighten color, and add freshness. When using this method, the two must be combined well. Different colored edible oils should be drizzled according to the flavor and color requirements of the dish, such as chicken oil (yellow), chili oil (red), tomato oil, sesame oil, and Sichuan peppercorn oil.
When drizzling oil, it must be done after the glaze is cooked to achieve a glossy and bright finish. Do not add too much oil at once or too quickly, as this can cause the oil to separate. Due to different cooking methods, the way of adding oil also varies. For dishes like stir-fries and quick-fries, oil is often drizzled in while tossing the wok at the end of cooking. For dishes cooked by dry braising, after the dish is removed from the wok, the remaining sauce in the wok is mixed with oil and then poured over the dish. After adding the bright oil to the glaze, the stirring and tossing should not be too fast to avoid the separation of oil and glaze.