1, cooking time can't be wrong. Everyone knows that the cooking time of a dish is very important, especially the chef's cooking skills and habits. Every link and step takes a very high time. More or less seconds may affect the taste and color of dishes. If you need to add water, turn on the tap now and turn it off after use. Switching on and off will waste a lot of time, and an carelessness will affect the final presentation of dishes, so many restaurant chefs don't turn off the tap when cooking.
2, to prevent the backlog of heat storage, to avoid burns. Many kitchen faucets are connected to electric water heaters or stoves for heating, so the water temperature will be very high at the moment when the faucets are turned on, and many chefs have experienced burns. Then constantly turning on the faucet during cooking can avoid the accumulation of heat storage, and then avoid the possibility of scalding caused by the high water temperature when it is turned on instantly.
Ensure the water is clean and then ensure the taste and hygiene of the dishes. Everyone knows that if there is water in the pipe, will it be stored? Hide evil and accept evil? Then continuously drain water when cooking, which can clean up the stored water and ensure that the water used for cooking is cleaner, healthier, fresher and the dishes are more delicious.
In a word, it seems like a waste of water for chefs in restaurants to turn on the tap while cooking, but they do it for a reason. Presumably, no one will waste water on purpose, so don't care too much. After all, they do it to make their work smoother and safer, don't you think?