Fat bloom on chocolate

A bar that has turned greyish-white looks spoiled, but usually is not. The coating is generally "fat bloom": cocoa butter that has migrated to the surface and recrystallized there.

Beutel Kuvertüre 75 % von Chocolat Bonnat

A chocolate bar that has developed a grey-white coating looks spoiled, but it usually isn't. The coating is typically fat bloom: cocoa butter that has migrated to the surface and recrystallized there.

The shock upon unwrapping is understandable nonetheless. The coating is often mistaken for mold, says the Bremen State Laboratory. Because this happens so easily, discolored chocolate often ends up in the trash, where it doesn't belong. This guide explains what happens on the surface of a bar, how to distinguish fat bloom from sugar bloom and actual spoilage, and what you can still do with a discolored bar.

What is actually happening on the bar

Chocolate is softer than it feels. At room temperature, a quarter of its fats are already liquid, explains Svenja Reinke of the Hamburg University of Technology. This liquid fat migrates outward through tiny cavities between the sugar, milk, and cocoa particles. On the surface, it recrystallizes. First, the bar loses its shine; later, a continuous grey to white film covers it.

The reason lies in the cocoa butter itself. It can solidify into six crystal forms that are chemically identical but differ in hardness and melting point. Only Form V has the properties expected of a good bar: shine, a clean snap, and a melt that begins on the tongue. After long-term storage, Form V also transforms into the most stable form, VI. During this process, the volume of the fat crystals increases, some cocoa butter is pushed to the surface, and the bloom forms there. Form VI only melts at 34 to 36 degrees Celsius, a few degrees too high for that delicate melt.

The Bavarian State Office and the Association of the German Confectionery Industry agree on what accelerates this process: heat, strong temperature fluctuations, and a fatty filling that releases its fat into the outer chocolate layer. Chocolate that was cooled uncontrollably during production also forms unstable crystals and develops bloom more easily.

Fat bloom or sugar bloom: how to feel the difference

There is a second white coating that originates quite differently. Sugar bloom is caused by moisture. If a bar moves from a very cold to a very warm environment, condensation settles on it and dissolves the sugar on the surface. When the water evaporates, the sugar remains in coarse, uneven crystals, and the layer looks like mold, though it has nothing to do with it.

You can tell the difference with your fingertip. Fat bloom looks spotty and matte, feels rather smooth, and begins to melt under your finger. Sugar bloom remains dry, rough, and granular and does not melt immediately. It cannot always be determined with absolute certainty at home, admits the Confectionery Association's Chocolate Info Center. It hardly matters what you do with the bar, as both coatings disappear as soon as the chocolate gets warm.

Can you still eat chocolate with fat bloom?

Yes. A white coating on chocolate is generally not spoilage, writes the consumer advice center, but rather cocoa butter that has settled on the surface; the chocolate can be eaten or processed further without any problems. The Lower Saxony State Office says the same about chocolate bunnies and pralines with a white layer. Mold is almost never involved with chocolate, writes ÖKO-TEST, because it consists of high amounts of fat and sugar and contains too little water.

What might suffer is the enjoyment, and experts do not fully agree on this. The Confectionery Association sees no effect on taste. The Bremen State Laboratory often finds that smell and taste remain unaffected, while the Lower Saxony State Office suggests the flavor might have faded slightly. What you see is certain: because appearance and texture are part of the enjoyment value, chocolate with extensive fat bloom is officially considered reduced in quality.

Indeed, this is a recurring topic, and it is a shame that the feedback—that the grey film is truly just a visual defect caused by cocoa butter migrating to the surface and does not reduce the quality of the chocolate—is sometimes misunderstood by customers as a dismissal. But it is the honest answer from a chocolate lover. Especially with products containing nuts, the probability is quite high that nut fat will also appear on the surface.

Manufacturers also state this openly. The Berlin-based manufacturer Sawade, whose pralines contain no chemical preservatives, writes in its notes on praline storage: A grey film is often fat bloom; it indicates temperature fluctuations, during which cocoa butter leaches out of the chocolate, and it is a visual defect.

How do you recognize spoiled chocolate?

The white coating alone is not a reliable indicator of spoilage, so it is worth looking for other signs. The Chocolate Info Center lists them: the chocolate smells pungent, tastes rancid, feels moist, has a visible furry coating or traces of pests, or the packaging was damaged. In that case, it should be discarded. More caution is advised with filled chocolates because fillings can be more sensitive than a plain bar.

Chocolate becomes rancid due to air and light. Both cause the fats to oxidize, which significantly changes the taste and smell, writes the Confectionery Association. A fine white web, on the other hand, is not bloom but the work of moth larvae: the Indianmeal moth and the Mediterranean flour moth also eat chocolate, and according to the German Environment Agency, they are usually introduced with already infested food or in cardboard boxes. Airtight containers keep them away.

The best-before date is the manufacturer's promise that unopened and properly stored goods will maintain their quality until that day. Many foods last significantly longer, and you can check whether they do by using your eyes, nose, fingers, and tongue. According to the Bavarian State Office, if stored correctly, dark chocolate usually lasts at least two years, milk chocolate about a year and a half, and white chocolate about one year.

How to store chocolate so it doesn't bloom

The Confectionery Association's formula fits in four words: cool, dry, dark, odor-free. Added to this is the temperature. The association and the Lower Saxony State Office specify 12 to 18 degrees Celsius, while the Bavarian State Office goes up to 20 degrees. More important than the exact figure is that it remains constant, because every warming, cooling, and re-warming increases the risk of the white coating. White chocolate absorbs odors particularly easily and should not be kept next to cheese, sausage, or fish.

We are fortunate that we decided on a geothermal heat pump with a cooling function 10 years ago. This allows us to store our chocolate at a fairly constant temperature all year round, while also ensuring relatively low humidity. This is a great advantage, especially in the summer months.

The Lower Saxony State Office does not recommend the refrigerator. Chocolate becomes crumbly there and loses its shine, and anyone who takes it out of the cold into a warm kitchen risks condensation and thus sugar bloom. Sawade recommends 15 to 18 degrees for pralines and suggests the red wine compartment of a wine cooler as the best place; an unheated pantry works, too.

It is important that you pack the chocolate airtight so it does not get damp. In general, it is not good to store chocolate in the refrigerator. It is better to keep it in a cool but dry place, but if it is too warm in the apartment, then the refrigerator is the better choice.

At home, I store opened chocolate in an airtight glass bowl. If your home gets very warm in the summer, you can wrap the bars in foil, for example, and place them in the refrigerator door. This is usually the warmest spot in the fridge. The wrapping is important as protection against moisture.

If you take the bar out again, let it reach room temperature in its sealed packaging before unwrapping it. Then no condensation will form, and the surface will remain as it was.

What can I do if chocolate turns white?

Melt it. As soon as the chocolate gets warm, the fat bloom disappears because the cocoa butter becomes liquid again, and sugar bloom also dissolves in the process. A discolored bar that otherwise looks, smells, and tastes normal is therefore well-suited for cake batter or the pot. It is less suitable for shiny coatings, decorations, or pralines, as its surface has already changed.

Anyone who wants the shine back must temper it: heat, cool, and heat slightly again. This sequence ensures that the cocoa butter preferentially solidifies in Form V; in the end, the mass is at about 30 degrees. Couverture runs thinner and more evenly than a broken-up bar because it contains more cocoa butter. According to the Cocoa Ordinance, it must contain at least 31 percent cocoa butter, while ordinary chocolate must contain at least 18 percent.

Which chocolate to use for what in the kitchen

It is a very good way of showing appreciation to turn a discolored bar into chocolate mousse or use it for baking. But honestly, I just enjoy the chocolate pure despite the white film. I often use Bonnat couverture for desserts or chocolate pastries, and I love hot chocolate with the 100% chocolate drops, as the milk already contains enough milk sugar for me. The 65% is good for desserts, the 75% as nibs in pound cake or as a chocolate glaze on muffins.

Chocolat Bonnat in Voiron makes both dark couvertures as small flat discs: the lighter one with 65 percent cocoa and the more robust one with 75 percent. Both consist only of cocoa, cocoa butter, and sugar. The 100% drinking chocolate, on the other hand, is nothing but cocoa and cocoa butter; dissolved in hot milk, it makes a dark, bitter cup that you sweeten yourself, or not.

For what	What	Our choice
Mousse and desserts	dark couverture, 65% cocoa	Bonnat, Couverture 65%
As pieces in pound cake, glaze for muffins	dark couverture, 75% cocoa	Bonnat, Couverture 75%
Hot chocolate, leftovers in batter or mousse	dark drops, 65% cocoa	Bonnat, Drinking Chocolate 65%
Hot chocolate, bitter	drops from cocoa and cocoa butter, 100% cocoa	Bonnat, Drinking Chocolate 100%
Pure, piece by piece	dark chocolate from a single origin, 75% cocoa	Bonnat, Madagascar
Creams, ganache, fresh berries	white chocolate without vanillin	Bonnat, Ivoire

The drinking chocolate drops melt in hot milk, and whatever is left in the bag goes into cake batter or a chocolate mousse. Madagascar comes from the Sambirano Valley in the northwest of Madagascar, with cocoa from this single origin. Ivoire is a white chocolate made from cocoa butter, sugar, and milk powder, without vanillin, and gives creams and ganache a fine, buttery sweetness.

And if a bar in the cupboard has turned grey after all: break it into a pot of hot milk and stir until nothing remains of it. No one will be able to tell from the cup what the bar looked like.

Chocolate for melting, baking, and pure enjoyment

For melting and baking: Couverture 65% and Couverture 75% by Chocolat Bonnat. For the cup: Drinking Chocolate 65% and Drinking Chocolate 100%. Pure and for light creams: Madagascar and Ivoire. You can find all the bars in our assortment under Chocolate Bars.

Sources