Many people pay attention to ingredients and seasonings when cooking but overlook the crucial factor of oil temperature. In fact, temperature has a significant impact on the texture and nutrition of a dish, and different dishes have different requirements for oil temperature. Generally speaking, cooking oil temperature can be divided into three types: hot pot hot oil, hot pot cold oil, and cold pot cold oil. Among these, hot pot hot oil includes warm oil, high heat oil, and blazing oil.
Warm oil. Commonly known as "five or six成热" (50-60% of maximum heat), it is about 140°C~180°C. At this temperature, the oil surface ripples and churns, with light blue smoke rising. When ingredients are added, numerous bubbles appear around them, accompanied by a sizzling sound. Warm oil is generally used for dishes like soft-fried shrimp, fried toon, dry-fried hairtail, and dry-fried pork loin. Additionally, when stir-frying vegetables and meat dishes, the oil temperature should be controlled at five or six成热.
Dishes like dry-fried hairtail and dry-fried pork loin require a second frying. This means the dish is fried until cooked, then removed, and fried again after the oil temperature has risen. The second frying requires seven or eight成热 oil temperature to achieve a crispy outside and tender inside. Using warm oil to stir-fry vegetables results in a beautiful color and minimal nutrient loss. If the oil temperature is too high, the ingredients may heat unevenly; if it's too low, the vegetables are prone to releasing water. When stir-frying meat, first stir-fry the meat until it turns pale, then add scallions and ginger to continue stir-frying, and finally add other ingredients.
High heat oil. Commonly known as "seven or eight成热" (70-80% of maximum heat), it is about 190°C~240°C. At this temperature, the churning of the oil surface calms down, with blue smoke appearing, and it makes a sound when stirred with a spoon. When ingredients are added, numerous bubbles appear around them, accompanied by a slight sizzling sound. It is generally suitable for cooking methods like deep-frying, pan-frying, and stir-frying.
If you want a sunny-side-up egg with a crispy golden-brown white and a runny yolk, you need to use seven成热 oil and keep the frying time short. This temperature is also suitable for stir-frying tofu because the tofu is more likely to break if the oil is too low. After adding the ingredients, turn off the heat to set the exterior with the high oil temperature, then use low heat to cook the inside through, and finally increase the heat again to color the ingredients. This method is suitable for making dishes like candied yams and candied sweet potatoes. Additionally, this temperature can be used to make crispy fried chicken, but you should not turn off the heat midway; maintain the temperature with continuous heating to achieve a crispy outside and tender inside.
Blazing oil. "Nine or ten成热" (90-100% of maximum heat), also known as blazing oil, is about 250°C~300°C. At this temperature, there is dense smoke, a scorching hot air, and blue smoke rising and rushing upwards, almost reaching the ignition point. When ingredients are added, large bubbles surge up, accompanied by a popping sound. This oil temperature is only suitable for the final step of steamed dishes and boiled dishes, such as for adding the finishing touch to boiled pork slices or scallion oil fish.
The method is to pour hot oil over chopped scallions, minced garlic, Sichuan peppercorns, and chili flakes. At this point, there will be a sizzling sound, and the hot oil can easily splatter, so be careful.