Bioethanol should be stored in an airtight container such as one of those we provide and kept away from direct sunlight or heat sources like radiators. Always ensure that the bottle cap has been replaced securely too – if it isn't water vapour will escape meaning less remaining product when you come to use it! It's also important not to overfill your burner with more than 30% EtOH content otherwise there simply won't be room for enough air inside making combustion impossible resulting in a waste of fuel and money.