If you’ve ever left chocolate lying around, you’d have noticed discoloration when you come back to it later. Why does chocolate turn white?

Often, when things get discolored, we assume that it’s gone bad or moldy – and usually that is the case! But what about chocolate?

The white discoloration we see in chocolate is actually harmless. Called the ‘chocolate bloom’, this whitening is caused by the particles within the chocolate moving through the chocolate to the surface and crystalizing there.

While totally harmless, the coloration definitely doesn’t look very nice. Are there ways to prevent it? Why does it happen to begin with?

We looked into the process from a scientific perspective to understand why this coloration happens and if there are any steps you can take to prevent it.

The Chocolate Bloom

So, we know the chocolate bloom is just because of the movement of particles, but there are actually different kinds of ‘blooms’ that can cause this!

Sugar Bloom

Sugar bloom is caused when there is too much moisture at the surface of the chocolate. Moisture is needed for the sugar in the chocolate to dissolve, but at some temperatures, this moisture will evaporate. When this happens, the sugar in the chocolate remains on the surface as crystals.

The individual crystals are really too small to see at first, but as more of them form, they become very visible. If this process repeats too much, the chocolate can become sticky and even whiter than usual.

Sugar bloom usually happens because the storage space the chocolate is kept in is either too humid, or it can happen if the chocolate is moved quickly from cooler to warmer temperatures with a very large difference. When this happens, the chocolate ‘sweats’ – that is, the moisture on the surface that was originally frozen, starts to melt and evaporate. This causes sugar bloom to happen much faster than it would otherwise.

Fat Bloom

Fat bloom is actually very similar to sugar bloom, with the only difference being – you guessed it – it’s caused by the fat, and not the sugar. Chocolate contains fat in the form of cocoa butter, which is mixed in the chocolate itself. Unlike sugar, which is dissolved in, cocoa butter is an essential and natural component of chocolate.

However, the fat and cocoa solids within the chocolate have different properties, which means that they behave differently at different temperatures. Therefore, at very warm temperatures, the liquefied cocoa butter in the chocolate moves through the pores and tiny spaces towards the surface. Here, it deposits as a white substance.

As time goes by, the liquid fat passing through the chocolate also tends to soften the chocolate as a whole, making it more porous, which results in this movement happening much faster.

Is ‘Whitened’ Chocolate Safe to Eat?

Even though it looks bad, chocolate that’s turned white is actually totally fine to consume. In fact, every year, millions of pounds of chocolate go to waste around the world because people are concerned about the white coloration, assuming it’s some kind of mold or fungus.

This is completely untrue, and has absolutely no effect on the chocolate’s taste, or whether it’s edible. Though it may not look so great, it’s completely fine to eat, and just as delicious.

How to Prevent White Coloration

Because it obviously doesn’t look too good, you’d wonder if there was any way you can prevent these white spots from showing up on your chocolate bars. It’s a lot better to eat Instagram-worthy food than to eat food that doesn’t look quite as appealing, isn’t it?

The answer is simple: storage. All you have to do is make sure you store the chocolate at reasonable temperatures – not too hot or too old – and that you don’t move it from cold to hot temperatures very fast or very suddenly.

On a manufacturer level, another way to prevent this is to make the chocolate less porous, to give the liquid fat very little room to make its way to the surface of the chocolate, but this still doesn’t address the problem of sugar bloom.

But regardless, despite how unattractive a splotchy bar of chocolate looks, it still feels just as good in your tummy.