Blanching is to remove blood and impurities from the surface of the ribs to make them cleaner and more hygienic. By placing the ribs in cold water, heating until the water boils and then continuing to boil for 3 minutes, you can effectively remove impurities and improve the taste and quality of the ingredients. More than 3 minutes will result in overcooked ribs and loss of chewiness, while less than 3 minutes will not completely remove impurities, affecting the taste and food safety. 3 minutes is an appropriate time range to ensure the effectiveness and taste of blanching ribs.