How long does a 9 kg BBQ gas bottle last?
How to work out how many barbecues you will get from a 9 kg LPG bottle, and how to avoid it running out mid-cook.
It depends on your BBQ
A 9 kg bottle holds roughly 440 MJ of energy (LPG has about 49 MJ per kg). How long that lasts depends on how many burners you use, how high you run them and how long you cook.
How to estimate it
Find your BBQ's total gas rating in MJ per hour on its compliance plate or in the manual. Divide 440 by that number to get the approximate hours of cooking at full power on every burner.
Example only: a BBQ rated at 40 MJ/h on full would get about 11 hours from a full bottle. Most cooks use fewer burners or lower settings, so real use is usually longer.
What makes it run out faster
Higher settings, extra burners and longer cooking times use more gas. Wind or an open hood can increase the time or heat setting needed, but not automatically consumption at a fixed input. Follow the manufacturer’s hood instructions. Cold weather can reduce gas delivery even when liquid remains.
Do not get caught out
Check before guests arrive. If the supplier permits a thermal check, use warm, never boiling, water. For weighing, before moving a portable bottle, turn off the appliance, close the bottle valve and disconnect according to the supplier’s instructions. Keep it upright, use scales rated for its full weight and subtract the tare in matching units, allowing for accessories not included in the tare. Do not lift a connected bottle or attempt to weigh a heavy installed cylinder yourself.
A WiseTank Bluetooth sensor (A$79) sits under a steel bottle and shows the remaining level in the TANK IOT app when your phone is nearby. It does not suit aluminium or composite bottles.