Space and Physics
PUBLISHED
Birthdays. We love to celebrate them. Presents, parties, singing, and the cake! The candles! The pomp and ceremony of blowing those babies out. It’s unfortunate when it all ends in your head being briefly engulfed in flames, though.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.That’s the fate of anyone unlucky enough to go Big Bad Wolf on a cake that’s been dusted with powdered sugar. However well intentioned, if it becomes airborne that sweet seasoning can be akin to festive tinder fuel.
Powdered sugar is surprisingly flammable when dispersed into the air like a cloud of dust. Its unique texture makes it vulnerable to igniting easily and burning rapidly, a scenario that has played out to disastrous effect in the sugar industry.
So infamous is powdered sugar that it’s considered an explosion hazard. An example of this unfolded in 2008 at the Imperial Sugar refinery in Georgia, US, where a chain reaction triggered by combustible sugar dust caused “a catastrophic explosion incident,” so says Dust Safety Science.
It begs the question, what is so uniquely hazardous about powdered sugar? It begins with surface area. When you have tiny particulates – like you find in the softer-than-silk texture of powdered sugar – you’re dealing with a material that has a high ratio of surface area to volume.
Compare it to a ball of wood the size of a baseball. A brief spark is unlikely to set that ball aflame. However, expose micron-sized specks of sugar to even the hint of a fire and it’s going to go up.
The same is true of other similarly-textured foodstuffs such as cornflour. It all centers around the five things you need for a dust explosion to occur:
- Fuel (i.e. your powdered sugar)
- Oxygen
- Heat
- Confinement
- Dispersion
In the case of a powdered-sugar birthday cake, you have your sugar for fuel, oxygen in the room (and your breath), heat from the candles, confinement from your dining room, and dispersion from your dedication to blowing out all those candles at once. When you understand the dangers of dust, it quickly becomes clear why you don’t want to huff a load of powdered sugar into a mini fire.
That’s what makes refineries like that run by Imperial Sugar such a site of concern for fire services. It only takes a small spark to set off a tiny speck of dust, but if there’s enough of it spread around, you quickly find yourself in big trouble.
If this has all got you eying your pantry with some suspicion, the good news is that you don’t need to throw out the sweet stuff. Powdered sugar is a perfectly safe – and delicious – addition to an everyday, candle-free cake. Just avoid piling it too high on your dear nephew’s birthday if you still want him to have eyebrows by the end of it.
