The temp at the mug lip cannot be greater the the temp of the liquid in it what can vary is how fast it heats up. If one has a mug made of material with exceedingly poor heat conduction the lip might never heat up very high as the liquid cools down before that. On the other hand that means that the mug is a heat insulator which means it cools down slowly.
We should have somebody with a thermal camera taking videos of SS and Ti mugs with hot water and see what happens.
We should have somebody with a thermal camera taking videos of SS and Ti mugs with hot water and see what happens.