Science Questions

Why do you get white blooms on refrigerated chocolate?

Why do you get white blooms on refrigerated chocolate? I was recently given a block of chocolate from a friend and to avoid it melting, as it’s currently summer here in Australia, i put it in the fridge. Finally got round to eating it today. When I unwrapped it I noticed there were white spots all over the place. William Isdale

Kat - I’ve been doing a life time of research into chocolate and yes,  you’re right. Bloom on chocolate this kind of white stuff you see in it is not harmful. You get two types of bloom on chocolate. You get cocoa butter bloom which is when the cocoa butter comes to the surface of the chocolate. You can tell if you’ve got cocoa butter bloom because it kinda feels a bit oily and greasy.  You can get sugar bloom and that’s when sugar crystals come out of your chocolate and that feels kind of granular. What’s causing it? Well, chocolateers think that what causes bloom is when you get temperature changes, big changes in temperature to chocolate. As it’s been hot in Australia and now you’ve put your chocolate that’s been in the fridge to keep it cold you’ve put it through quite a big temperature differential and then got it back out of the fridge again. That’s caused the bloom. It’s probably best to keep your chocolate at a cool, stable temperature – not necessarily in the fridge.

January 2009