How to know or identify stainless steel insulated bottle/mug not vacuum any more?
I bought a Stanley coffee mug (20oz) not too long ago, the seal mostly worked and the coffee stayed hot for a few hours, but one day I noticed it started making a noise. Air had begun leaking out of the “vacuum” and was bubbling past some coffee on the side of the cup. After that I noticed the coffee mug would get warm to touch, and I knew the “vacuum” no longer existed. I still sort of used it until it developed a new plasticy funk smell, that ruined the coffee drinking.
As what he described, when your stainless steel vacuum coffee mug/bottle/flask get warm to touch, it means “vacuum” no longer existed due to the vacuum layer can stop heat transport to outer wall to have heat retention function, that’s why it called “vacuum insulated bottel flask”.
The reason why it has this problem, poor manufacturing, poor quality inspection can both cause this problem, except for you drop stainless steel vacuum bottle flask on the floor to damage it, you have right to get a free return due to it is manufacturer issues.