Does bioethanol fuel evaporate?
If you find that there is still liquid underneath your burner after you turn off your fire, do not worry. There is nothing wrong with it and you will be able to use the fuel at a later date. It is important to note, however, that bioethanol fuel is mostly alcohol so it will evaporate over time.
In order to prevent evaporation it is a good idea to put only as much fuel as you intend to use into the fuel box at any one time.
For example, if you wish to enjoy your ethanol fireplace for three and a half hours, you can pour one litre of fuel into the box (or even less if you intend to keep the box half-open). If you still have fuel left at the end of the session, you should close the lid of the fuel box to minimise evaporation.