How should tank insulation be evaluated when buying a lifting noodle cooker?

Insulation quality shows up in three measurements, not in a catalogue figure. Ask for the lagging material and thickness, then test: minutes for an 80°C tank to fall to 60°C once power is cut, outer-skin temperature rise while the basket keeps boiling at full load, and how often the element cycles over an eight-hour noodle service. Where foil vapour barriers or a drainage slope are missing, steam wicks into the cavity, water pools between skins, the shell runs hot and insulation decays; scan the side panels and bottom head with an IR gun at handover.