Why Is My Chocolate White? Sugar Bloom And Fat Bloom

That white or grey film is bloom, and there are two kinds. Either cocoa butter has migrated to the surface and recrystallised there, which is fat bloom, or sugar has dissolved in surface moisture and been left behind when the water evaporated, which is sugar bloom. Both are rearrangements of material that was already in the bar. Neither is mould.

Most answers stop at "it is fine, eat it". True, and not very useful. Which of the two you have tells you where the problem happened: your cupboard, the delivery van, or a tempering line months before the bar reached you. Working out which takes ten seconds.

Fat bloom: cocoa butter that moved

Cocoa butter can crystallise into six polymorphic forms, meaning six ways the same fat molecules can pack together. Tempering is the controlled heating and cooling that steers it into form V, the one that gives a bar its gloss and its snap. Form VI is more stable still, and much harder to make on purpose.

Lonchampt and Hartel, reviewing the subject in the European Journal of Lipid Science and Technology in 2004, are blunt about how much remains unsettled. They state that the specific mechanisms of fat bloom still remain largely unknown, and sort bloom into four origins: under-tempering or melting, over-tempering, incompatible fats and fat migration, and storage bloom. Chocolates that bloom in storage have made the transition from form V to form VI, and the bloom crystals are themselves form VI. But a bar can make that transition without ever looking bloomed, and the review says it is not clear why.

Storage temperature is where the review gets usefully specific. Below 18 degrees Celsius storage bloom is inhibited, though it can still appear after more than a year. Between roughly 18 and 30 degrees it increases as the temperature rises. Above about 32 to 34 degrees cocoa butter partly melts and recrystallises into unstable forms, producing rapid bloom with large white spots. Fluctuation makes it worse: cycling shortens the time before bloom appears, which is why laboratories use it to accelerate bloom tests.

One study cited in that review found bloomed chocolate melting at around 34 degrees against about 30 degrees for normal chocolate. Four degrees sounds trivial. It is the difference between a button that goes at body temperature and one that sits there.

Sugar bloom: water that visited

Sugar bloom has nothing to do with crystal forms. Writing in Food Technology for the Institute of Food Technologists in 2004, J. Peter Clark puts the mechanism in one line: moisture on the surface extracts some of the sugar, and when the water evaporates it leaves a white deposit.

His industrial example is a cooling tunnel whose outlet is set too cold, so pieces leave it below the dew point of the packing hall and condensation forms on them at once. The domestic version is a bar taken from the fridge and left on a warm worktop. Identical physics, smaller scale.

Telling them apart in ten seconds

The rub test works because of the melting points above. A fingertip sits close to the range at which bloom crystals soften. A sugar deposit is not fat and has no reason to give way.

Why is my chocolate white after a spell in the fridge?

The fridge is rarely the problem. The journey out of it is. A cold bar meeting warm kitchen air drops the air at its surface below the dew point, water condenses, sugar dissolves into it, the water goes, the sugar stays. That is Clark's cooling tunnel on your worktop. If a heatwave leaves you no choice, seal the chocolate and let it return to room temperature still sealed, so condensation forms on the wrapper. The better default is a cool, dark, dry cupboard held steady below 18 degrees, the figure at which the lipid review says storage bloom is inhibited.

Cocoa butter content is the other half of it, because cocoa butter is what migrates. Under the Cocoa and Chocolate Products (England) Regulations 2003, anything sold in England as "chocolate" must contain not less than 35 per cent total dry cocoa solids, of which at least 18 per cent is cocoa butter. A 77 per cent bar carries a good deal more than that floor, and more fat means more fat available to move. For how the two starting materials differ, see our note on raw cacao and cocoa powder.

What is actually in a Chaski tube

A 600 g tube of 77 per cent dark buttons, made from single-origin Peruvian and Ecuadorian cacao ground at low temperature, sweetened with coconut sugar, with Lion's Mane as a fruiting body extract and Cordyceps sinensis mycelium. No emulsifiers, no seed oils, no palm oil. The Ginkgo Biloba component is being replaced by 200 mg of Tremella fuciformis, a 10:1 fruiting body extract, per daily dose, and tubes are in that transition. Every batch is tested for lead, cadmium and pesticides. Daily dose on the pack is four buttons, and the button shape changed in mid-2026 with the recipe unchanged. The full ingredient list sits on the Chaski Cacao product page, with a separate note on coconut sugar and refined sugar in chocolate and the rest of the writing in the Chaski guides library.

Go and find the bar you were worried about. Press a thumb on the white patch for five seconds. If it smears, it spent time somewhere warm, or somewhere that could not hold a temperature. If it stays gritty, it met condensation. Then move what is left to the coolest steady shelf you have.

Sources

1. Lonchampt P and Hartel R W, European Journal of Lipid Science and Technology, 2004
2. Clark J P, Food Technology (Institute of Food Technologists), 2004
3. The Cocoa and Chocolate Products (England) Regulations 2003, legislation.gov.uk