Why can’t the protein shake cup be washed with boiling water?

　　I recently bought a bucket of Optimum protein powder and a Shaker Bottle. There is no indication that hot water can not be used in the instructions for the protein powder. However, I saw such a warning in the Shaker Bottle. The above picture says To be very clear, please do not pour hot water or soda into the Shaker Bottle. The main reason is that the pressure inside the cup will rise. If the pressure difference between the inside and outside reaches a certain level, the lid may pop open and the liquid inside will Spill out. It has nothing to do with what kind of hot water destroys protein activity and affects absorption…Since foreigners generally use Shaker Bottles, they also strictly follow the notice of not using hot water. As a result, it becomes impossible to use hot water. Made protein powder