Plain flour has a lot of chemical energy packed into it. When the flour is in a clump or pile it does not ignite although it may blacken. This is because there is not enough flour exposed to the oxygen in the air. Aerosolising the flour exposes it to much more oxygen allowing a self sustaining combustion reaction to occur when an ignition source is nearby. In this article, the author presents a demonstration that can be used to illustrate the effect of increased surface area on chemical reaction rates. Aerosolising the flour vastly increases its surface area and therefore increases the reaction rate spectacularly. It can also be used to demonstrate surface area to volume ratio in biology lessons after the completion of a potato cube and iodine practical. Point out that each bit of flour dust would have a much greater surface area to volume ration than a clump of flour. The flamethrower also demonstrates the massive amount of chemical energy stored in carbohydrates.