First, what is the problem with blending hot liquids? They release copious steam when agitated, and steam is super hot and produces tremendous pressure when confined (think: locomotive weighing 100 tons, moved by steam.) If you put a hot liquid in your blender and put the airtight lid on, it will invariably come blasting off the moment your machine revs up, splattering you and your kitchen with scalding liquid. Big, dangerous mess. Thanks to Carmine for posting this humorous video: