Fat Bloom vs Sugar Bloom: Why Chocolate Turns White and How to Prevent It
You open a bar you have been saving and find a pale, dusty film across the surface. That is bloom, and it comes in two different forms with different causes. Knowing which one you have tells you how to prevent it next time.
Fat bloom
Fat bloom happens when cocoa butter migrates to the surface and recrystallizes in an unstable form. It looks like a greyish, streaky or swirled film and feels smooth or greasy rather than gritty. Common causes are poor tempering, storage at warm or changing temperatures, and fillings with oils or nut pastes that move into the chocolate over time.
Sugar bloom
Sugar bloom happens when moisture reaches the surface, dissolves some of the sugar, and then evaporates, leaving sugar crystals behind. It looks like a dry, rough, whitish coating that feels gritty. The usual cause is condensation, for example when cold chocolate is brought into a warm, humid room, or when it is stored in a damp place.
How to tell them apart
| Fat bloom | Sugar bloom | |
|---|---|---|
| Look | Greyish, streaked, swirled | White, dusty, speckled |
| Feel | Smooth, greasy, melts on touch | Dry, rough, gritty |
| Main cause | Temperature swings, poor temper | Moisture and condensation |
Is it safe?
Bloom affects appearance and texture, not safety. If the chocolate smells normal and has been stored properly, it can be eaten. The mouthfeel is often less smooth, so many people prefer to use bloomed chocolate in baking.
How to prevent bloom
- Temper properly so the cocoa butter sets in a stable form. See our tempering guide.
- Store at a steady, cool temperature, around 16 to 18 °C, away from sunlight and heat sources.
- Keep it dry and sealed, away from strong odors.
- Avoid the fridge unless the chocolate is tightly wrapped, and let it reach room temperature before unwrapping.
- Mind the filling, because oils from nut pastes can migrate into the shell.
What to do with bloomed chocolate
Chop it and melt it for ganache, brownies, sauces or hot chocolate. You can also re-temper it for coating or molding, which restores gloss and snap.
Key takeaways
- Fat bloom is greasy and grey; sugar bloom is dry and gritty.
- Bloom is not a safety problem.
- Good tempering and stable, dry storage prevent most bloom.
- Bloomed chocolate works well in baking.
Frequently asked questions
Is bloomed chocolate safe to eat?
Yes. Bloom changes appearance and texture, not safety, as long as the chocolate has been stored properly and smells normal.
Can bloomed chocolate be fixed?
You can melt and re-temper it, or use it in ganache, baking or drinks.
Should chocolate be stored in the fridge?
Generally a cool, dry cupboard is better. If you must chill it, wrap it airtight and let it warm up before opening to avoid condensation.