by Uncle bob » Sun Jan 26, 2020 7:18 pm
i can vouch for stanley flasks ....i've a 1.4 ltr, a 750 ml ....and a 700ml food flask.
the 1.4 ltr is the biggest and heaviest ....but this one keeps my drinks really hot the longest 24hrs is no problem for it .
The 750 , 12 - 15hrs max
The 700ml food flask , 8 - 12hrs max
i would say i have a good few years knowledge of using flasks......worked on the buildings all my working life ...been camping since i was a kid using cork stopper flasks.
but my advice is NEVER buy a flask with push button to pour stopper ....it leaches out the heat ....the stopper is the flasks weakest thermal point ...my 1.4 ltr has the smallest stopper compered to its insulated body thickness...the 750ml has the same size stopper but its body is less thick .....the reason the food flask is so poor heat retention wise, is the really wide stopper......(its a new purchase )....i hope to increase this with the glove in lid
if you want to improve your flask heat retention put a cheap poundland thermal glove in the cup/lid ..screw lid tight and try that.....hope this helps ...ive walked , winter camped....but not above 1,500 - 2000 ft .