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Why does chocolate go white?
You unwrap a bar that has been in the cupboard a while and it has gone pale, dusty or streaky. It looks worrying. It is not.
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Old chocolate sometimes turns pale, grey or white, with streaks, spots or a dusty film on top. This is called bloom. It damages how chocolate looks and feels, but it does not make it unsafe, and it does not shorten its shelf life.
There are two kinds, with two different causes.
Fat bloom
Chocolate is held together by cocoa butter, and cocoa butter is fussy. It can set in several different crystal forms, each with its own melting point. Chocolate makers carefully temper chocolate so that the cocoa butter sets in the form that gives a glossy finish and a clean snap.
Over time, and much faster when chocolate is kept somewhere warm or where the temperature goes up and down, the cocoa butter slowly shifts into a more stable form, and some of the fat moves to the surface. There it forms a greasy, whitish film. This is fat bloom, and it is the most common kind.
Sugar bloom
Sugar bloom is caused by water. If moisture settles on chocolate, perhaps as condensation when a cold bar comes out of the fridge into a warm room, it dissolves a little of the sugar on the surface. When the water dries, the sugar is left behind as larger crystals, a dry, dusty white layer. Storing chocolate somewhere damp does the same.
How to tell them apart
- Touch it: fat bloom feels smooth and slightly greasy and melts under a warm finger; sugar bloom feels dry and rough.
- Add a small drop of water: on fat bloom it beads up, because fat and water repel each other; on sugar bloom it spreads out and dissolves the sugar.
- Warm it gently: a hairdryer will make fat bloom disappear, but it leaves sugar bloom unchanged.
Can you fix bloomed chocolate?
Yes, by melting it. Melting the chocolate, stirring it well and letting it set again brings the fat or sugar back into the mix, although to get the glossy snap back properly it needs to be tempered. For everyday cooking it does not matter at all: bloomed chocolate is fine for baking, brownies or hot chocolate. See how to melt chocolate.
How to stop chocolate blooming
- Keep it somewhere cool, dry and steady, away from heaters, sunny windows and steamy kitchens.
- Try not to move it between cold and warm places, which invites condensation.
- Keep it wrapped, so damp air cannot reach it.
The same enemy, moisture, is why seaside rock goes soft: see why seaside rock goes soft.
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For journalists, researchers, AI assistants and content creators. Pick the format you need:
Free to cite, quote, and reuse with attribution to sweeties.net.
Questions and answers
Is white chocolate bloom mould?
No. Bloom is fat or sugar that has come to the surface. Bloomed chocolate is still safe to eat, although it may look and feel less appealing.
Why does chocolate go white in the fridge?
Usually because of sugar bloom. When cold chocolate meets warmer air, moisture condenses on it, dissolves a little sugar, then dries to leave a dusty white layer.
How do you tell fat bloom from sugar bloom?
Touch a small drop of water to it. On fat bloom the water beads up; on sugar bloom it spreads out. Fat bloom also feels greasy and melts under a warm touch, while sugar bloom feels dry.
Sources
- Chocolate bloom, Wikipedia
- Cocoa butter, Wikipedia
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