Why does chocolate get a white coating? Probably everyone who loves chocolate has asked themselves this question because they have repeatedly encountered such a concept as whitish or “blooming” chocolate.
This strange phenomenon has been a chocolatier’s trick since the world began making sweetened bars in the mid-1800s when British confectioner Joseph Fry discovered that chocolate could harden if melted cocoa butter was added to Dutch cocoa.
In fact, white coating is still “the most common defect in finished chocolate products,” says Michael Laiskonis, pastry chef at the Institute of Culinary Education. Here’s what you need to know before your next trip to the candy aisle.
What is the chocolate coating?
There are two types of chocolate coating: fat and sugar. The fatty coating looks a bit like “the surface of the moon,” says Nick Sharma, a molecular biologist turned cookbook author. Chocolate can appear chalky, with lighter brown and gray streaks, says Christopher Elbow, owner of the eponymous chocolate shop in Kansas City.
Meanwhile, sugar “graying” is usually characterized by speckled white dots or even a dusty appearance, says Suzanne Yoon, founder of Stick With Me Sweets, a New York chocolate shop.
However, it’s not always easy to tell the difference. According to Laiskonis, fat and sugar “graying” can occur simultaneously. “Sometimes the visual effects are minor, and the chocolate just loses its glossy shine.” Despite some external similarities, fat and sugar graying are caused by different factors.
What causes chocolate to bloom?
Fatty “graying” usually occurs during the manufacture or storage of chocolate. When properly tempered-a heating and cooling process that stabilizes and hardens cocoa, cocoa butter, and sugar-chocolate becomes “shiny and crispy and melts just below body temperature,” says flavor scientist Ariel Johnson. But if you let the piece of chocolate get too hot, the fat crystals will melt and “recrystallize into an unstable shape,” says Laiskonis. This is what creates the appearance of “fat streaks on the surface of the chocolate,” adds Yoon.
Sarah Flanders, co-owner of Salt Rock Chocolate Co. sometimes encounters greasy patches when she tempers chocolate to make apricots, Grape-Nuts bars, and cashew nut clusters. “If the molten chocolate is too hot when we process it, the cocoa butter will separate, rise to the surface and harden, leaving a residual white fat,” she says. “This can also happen if the chocolate doesn’t harden quickly enough,” she explains.
According to Laiskonis, various other nasties can cause greasy whitening in chocolate, such as oils migrating outward from the center of chocolate-covered nuts. Although all types of chocolate can develop fatty deposits, “dark chocolate is the most susceptible,” says Laiskonis. “It is generally believed that the small amount of milk fat found in milk and white chocolate may prevent its formation to some extent.”
On the other hand, sugar whitening occurs when chocolate comes into contact with moisture. Sugar is hygroscopic, says Sharma, which means it “absorbs moisture.” If the air is particularly humid, the sugar will absorb the liquid, dissolve, and then turn into larger crystals that will settle back on the surface of the chocolate.
According to Laiskonis, direct contact with water or rapid environmental changes, such as moving the product from cold to warm temperatures, can cause the bar to condense, which also leads to sugar graying.
Chocolate with a white coating: can you eat it?
The chocolate coating may look unappetizing, but it is absolutely safe to eat. However, this does not mean that you will want to eat it, as the taste and texture may vary.
“The bloom usually robs chocolate of some of its most enjoyable qualities,” says Laiskonis. According to Elbow, chocolate with a fatty coating can be too similar to cocoa butter. The texture is somewhat “waxy or crumbly compared to properly tempered and stored chocolate,” Johnson adds. According to Laiskonis, chocolate with a sugar coating is likely to have a “grainy” mouthfeel.
White coating on chocolate – how to remove it?
It is not always possible to avoid chocolate “graying,” but proper storage certainly helps. “To protect your bars from both types of blooming, make sure they are well wrapped and store them in a cool, dry place,” says Johnson. This rules out the refrigerator, “which is too humid.” If you live in a place so hot that the refrigerator is your only option, he suggests covering the chocolate tightly with plastic wrap and putting the bars in a zip-top bag to prevent moisture from seeping through.
What to do if chocolate turns white?
Chocolate discoloration doesn’t mean the end of your treats. “Chocolate is still great for melting, baking, or cooking,” says Elbow. Sharma suggests melting the blooming chocolate to make a filling, or cutting it up and using it in baked goods like cookies. When the problem of sugar whitening arises, Laiskonis uses it to make a mousse or ganache, “where the larger sugar crystals will dissolve,” he says. But you can also just eat it.