pvtdirtpusher

pvtdirtpusher t1_irezj2n wrote

As said by others, the opening and closing is the killer. Not only are you exposing the contents of the thermos to air in the short term, you literally taking hot liquid and replacing it with room temperature air. Meaning that the thermos has both less thermal mass ( an subsequently easier to heat up) but now has to equalize in temperature with the room tell air now inside the closed thermos.

Fully primed, filled and left untouched,, I would expect it to last close to full time they specify

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