Why Does Chocolate Turn White? Unraveling the Sweet Mystery

Chocolate turns white due to a phenomenon called "chocolate bloom," which is the formation of white or grayish streaks or spots on the surface of the candy. There are two main types of bloom — sugar and fat — and they have different causes.

Sugar Bloom

Sugar bloom is normally caused by surface moisture. The moisture causes the sugar in the chocolate to melt. Once the moisture evaporates, larger sugar crystals form, creating a white, powdery coating on the surface of the chocolate.

This type of bloom can make the chocolate look dull and matte, and the texture may feel slightly gritty when touched. If this process is repeated, the surface can become sticky and even more discolored.

Sugar bloom is most often the result of overly humid storage, but it can happen when the chocolate has been stored at a relatively cool temperature and is then moved too quickly into much warmer surroundings. When this happens, the chocolate sweats, producing surface moisture.

Fat Bloom

On the other hand, fat bloom is caused by the crystallization of fats, typically cocoa butter, within the chocolate.

This reaction occurs when cocoa butter fats migrate to the surface due to temperature fluctuations, and these fats crystallize in an unstable form, resulting in a whitish or grayish appearance on the chocolate's surface and an altered texture. The chocolate may be slightly greasy when touched.

Luckily for chocolate lovers, sugar and fat bloom are cosmetic issues rather than signs of spoilage. Although it might look a little less appetizing than a lustrous, rich chocolatey-brown piece of candy, bloomed chocolate is still okay to eat.

However, you may find the texture of sugar-bloomed chocolate to be a bit grainy on the outside, but it should still taste good. To prevent this from happening to your chocolate, simply use proper storage methods. More on that later.

Retempering bloomed chocolate is a process that involves melting and then carefully cooling the chocolate to restore its proper crystalline structure and appearance. This method is especially effective for chocolate that has experienced fat bloom (when cocoa butter separates from the cocoa solids).

Here's what you'll need:

Now you're ready to retemper that chocolate:

1. Chop the Chocolate

Begin by chopping the bloomed chocolate into small, even-sized pieces. This helps it melt evenly and facilitates the tempering process.

2. Melt the Chocolate

If using a microwave, place the chopped chocolate in a microwave-safe bowl. Microwave in short, 15- to 20-second bursts at a medium-low power setting (50 percent power) to avoid overheating. Stir between each burst. Continue microwaving and stirring until the chocolate is almost fully melted.

If using a double boiler, fill a pot with water and bring it to a simmer. Place the chopped chocolate in a heatproof bowl and set it over the simmering water, making sure the bowl doesn't touch the water. Stir the chocolate gently until it melts completely.

3. Check the Temperature

Use a food thermometer to monitor the temperature of the melted chocolate. The temperature varies depending on the type of chocolate.

4. Seed the Chocolate

To encourage the proper crystallization of cocoa butter, add a small amount (about 10–20 percent) of unmelted chocolate pieces to the melted chocolate. Stir continuously until these pieces melt and the mixture reaches the target temperature.

Once you've reached the correct temperature, remove any remaining unmelted chocolate pieces from the mixture.

5. Cool and Test the Temper

Continue stirring the chocolate gently until it becomes smooth and glossy, which indicates that it has been properly tempered. To verify that the chocolate is properly tempered, dip a knife or spatula into the chocolate and let it cool at room temperature. It should harden with a glossy finish.

You can now use the tempered chocolate as needed in your recipe or for dipping and molding. If you're not using it immediately, keep it in a dry airtight container.

Sugar bloom is typically irreversible once it occurs because it involves the recrystallization of sugar on the chocolate's surface due to moisture exposure. However, you can still try to improve the appearance of the chocolate by gently brushing off the loose sugar crystals with a dry, soft brush or a clean cloth.

Keep in mind that this won't completely restore the chocolate to its original texture, but it can make it more visually appealing. To prevent sugar bloom in the first place, store chocolate in a cool, dry place, away from moisture and temperature fluctuations.

The best way to avoid chocolate bloom is to store the candy properly. Since the treat can easily absorb flavors from food or other products situated nearby, chocolate should be tightly wrapped and stored away from pungent odors.

The ideal temperature for storage is somewhere between 65 and 68 degrees Fahrenheit (18 and 20 degrees Celsius), with no more than 50–55 percent relative humidity. If stored properly, you can expect milk chocolate and white chocolate to be good for up to six months.

Dark chocolate with a high cocoa content, typically around 70 percent cocoa or higher, tends to have a longer shelf life than other types of chocolate. Due to its lower sugar content and higher levels of cocoa butter, dark chocolate is less susceptible to sugar and fat bloom and can last up to a year if stored in ideal conditions.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.

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