It keeps the heat for more than 12 hours without worry. I had the opportunity to put the hot tea and it was still super hot 13h later, the above is EXCELLENT I waited a bit before writing my review and I did well, because at the beginning, there was no problem with the tight side of the cap (the one with the button) but after a few uses, n is already the case ... when the thermos is shaken, there are drops which escape ... nothing major will say to me since there was still the second cap ... But I 'm using in hiking, the bottle is shaken constantly and I can not be certain that one day it will not end up dripping down my backpack (this is the big worry for us hikers). So, initially, I recommend to everyone but now I refrain and wait to see if it gets worse.