Most of the heat escapes a vacuum flask through the lid, placing a sheet of aluminium foil over the sealed lid, secured with rubber band will double the time your tea, coffee or soup stays “stove-hot.” I personally clocked near boiling water stay steaming same temp hot for 2.5 hours, before I opened the lid to end the experiment, more than double the usual insulation time, without the cover.
Hey Grouf...welcome back to Twitter!
thanks for informing me, didn't know
🔥Love it!
https://twitter.com/dgrouf?s=21&t=4F9MNY5ZbX25kYfwpn8RTA
Dr are you back on twtr ?