Have you ever unwrapped your favourite chocolate bar only to find it’s coated in mysterious white film? If so, you’re not alone. I’ve had this happen on several occasions and I know it can be pretty scarry to see it first time, because it looks like a mouldy chocolate! Well, the good news is that the white powdery film is not a mould, but something that’s called chocolate bloom.
My chocolate making courses students often ask me “Why Does Chocolate Turn White?”, so I thought in today’s blog post I’ll dive into the science of chocolate bloom, explain the difference between fat and sugar bloom, and look into how these conditions affect your chocolate’s appearance and texture.
Why does chocolate turn white? The short answer
Chocolate turns white due to a process known as ‘bloom,’ which can occur in two forms: fat bloom and sugar bloom. Fat bloom happens when cocoa butter fats separate from the chocolate and recrystallize on the surface, often due to improper storage conditions, temperature fluctuations, or poor tempering during production.
Sugar bloom occurs when moisture comes into contact with the chocolate, dissolving the sugar, which then recrystallizes on the chocolate’s surface as it dries. Both types of bloom are harmless and do not significantly affect the taste of the chocolate.
What is the difference between fat bloom and sugar bloom in chocolate?
Fat bloom in chocolate is caused by separation and recrystallization of cocoa butter within the chocolate, which can occur due to temperature changes or poor tempering, resulting in a whitish, streaky surface. The cocoa butter is lighter than the cocoa mass and when it melts and separates it travels to the surface of your chocolate, which is why you can see it as a white marks. In case you didn’t know, cocoa butter has off white colour.
Sugar bloom, on the other hand, is the result of moisture coming into contact with the chocolate, dissolving the sugar. When the moisture evaporates, it leaves behind a rough, white residue of sugar crystals on the chocolate’s surface, which is why your chocolate might taste a bit grainy.
The sugar bloom also leaves map and flower like creations, whereas the fat bloom looks usually like white streaks over your chocolate.
When chocolate goes white, is it safe to eat?
Yes, chocolate that has turned white due to bloom is safe to eat. The whitish coating is a result of fat or sugar crystals rising to the surface, and it does not indicate that the chocolate is spoiled. I know people might think that the white powder is mould, but it’s not.
You can test the chocolate bar by running your finger over the affected area and if it doesn’t leave any mark on your finger, it’s just a chocolate bloom, nothing more and you are fine to eat your chocolate. If it was a mould, you would be also able to smell it, as the chocolate would have mouldy smell. Chocolate bloom is odourless.
But to be on a safe side, just double check the chocolate expiry date – although it’s fine to eat expired chocolate, the chocolate still needs to be in a good condition.
How to prevent chocolate from going white
To prevent chocolate from turning white, store it in a cool, dry place at a consistent temperature, ideally between 17 and 20 degrees Celsius. Don’t store your chocolate next to a heat source like a radiator or a cooker to prevent temperature fluctuations that can cause fat bloom.
It is also important to keep chocolate away from moisture, ideally in airtight container to avoid sugar bloom.
Does chocolate turn white if you store in the fridge?
Yes, chocolate can turn white if stored in the fridge due to the humidity and the presence of moisture, which can lead to sugar bloom. On top of that, the cooler temperatures can cause fat bloom if the chocolate experiences temperature fluctuations when taken in and out of the fridge.
I really don’t recommend to store chocolate in the fridge, as it is often too humid and can lead to bloom. I know that some people like to eat cold chocolate, which is why they keep it in the fridge, but don’t be surprised if your chocolate goes white.
Can the white film on chocolate affect its flavour or texture?
Yes, the white film on chocolate, which results from either fat bloom or sugar bloom, can affect its flavour and texture. While the chocolate is still safe to eat, bloom can cause the chocolate to have a grainy or crumbly texture and may dull the flavour, making it less smooth and less enjoyable to eat compared to when it is in its optimal state.
I’ve eaten bloomed chocolate to test it and to be honest, although I can tell the difference, I’m not sure that most people would be able to. The difference can be quite subtle, especially with the fat bloom (where the cocoa butter just separated from the rest of the chocolate) as the chocolate dissolves really quickly in your mouth and the taste is pretty much the same.
It’s slightly different with the sugar bloom, because it also causes the sugar to crystalise, which means that you can taste the small crystals in the chocolate.
Is chocolate going white an indication of poor quality or old chocolate?
Chocolate going white (chocolate bloom) is not necessarily an indication of poor quality or old chocolate. I’ve seen it in both high-quality and lower-quality chocolates and can happen to fresh chocolate as well. Bloom is often a result of how the chocolate is stored or handled rather than its inherent quality or age.
If you get a chocolate bar from a supermarket and it’s turned white, it’s probably the way how the chocolate was stored after it left the chocolate factory. Up to that point, the chocolate tempering process and environment are perfectly controlled, but once the chocolate leaves the factory is susceptible to any changes in temperature and humidity.
If you get a chocolate bar from a smaller chocolate producer, it could also be because the chocolate wasn’t tempered properly. Chocolate tempering is a notoriously difficult part of chocolate making and it’s quite tricky to get right as it also depends on external temperatures and humidity in the room.
Can chocolate with white film (sugar bloom) still be used for baking or cooking?
Yes, bloomed chocolate can still be used for baking or cooking and that’s probably the best use for it. The bloom affects the appearance of the chocolate but not its safety or functionality in recipes.
When melted, the cocoa butter and sugar crystals will recombine, so the bloomed chocolate will perform just as well as non-bloomed chocolate in most baking and cooking recipes, such as in cakes, brownies, cookies, or chocolate sauces, that are prepared with melted chocolate.
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This blog post was originally written on 2 March 2024 and last updated on 2 March 2024
