Why Some Chocolates Bloom and How to Prevent It

Chocolate is treasured for its glossy shine, satisfying snap, and rich melt-in-the-mouth texture. Yet anyone who has stored a bar too long or found an older bag of chocolate chips has probably encountered a chalky white coating across the surface. This phenomenon, called chocolate bloom, is one of the most common quality issues that confectioners, bakers, and chocolatiers face.

While bloom does not make chocolate unsafe to eat, it does affect appearance and texture. For bakeries, caterers, and foodservice professionals who rely on attractive presentation, understanding the causes and prevention of bloom is essential. At Baker’s Authority, where bulk and wholesale chocolate is supplied to commercial kitchens across the country, we know the importance of keeping ingredients fresh, stable, and ready to perform.

This article explains why chocolate blooms, the differences between fat bloom and sugar bloom, and the practical steps that professionals and home bakers alike can take to prevent it.

Chocolate bloom refers to the whitish or grayish coating that sometimes appears on the surface of chocolate. Though it may look like mold, it is not. Instead, it is either cocoa butter crystals (fat bloom) or sugar crystals (sugar bloom) that have risen to the surface due to changes in temperature or humidity.

Bloom affects only the look and mouthfeel of chocolate. The product remains safe to consume, but the visual quality and smooth texture that bakers want may be compromised.

There are two main types of bloom:

• Fat bloom – caused by the movement and recrystallization of cocoa butter.
  
  

• Sugar bloom – caused by moisture dissolving and recrystallizing sugar on the surface.

Understanding the difference between these types helps identify the cause and apply the right prevention methods.

Fat bloom occurs when cocoa butter separates from the cocoa solids in chocolate and migrates to the surface. Once there, it re-solidifies, leaving a dull white or gray film.

1. Temperature fluctuations: If chocolate is exposed to heat and then cooled, the cocoa butter can melt and re-solidify in unstable crystalline forms. For example, chocolate left in a warm delivery truck and later stored in a cool pantry may exhibit fat bloom.
   
   

2. Improper tempering: During production, chocolate must be tempered to form stable crystals of cocoa butter. If tempering is rushed or skipped, unstable crystals form, which later rearrange and rise to the surface.
   
   

3. Extended storage: Over time, even well-tempered chocolate can develop bloom if subjected to fluctuating conditions.

Fat bloom generally looks streaky and feels smooth to the touch. Rub a small piece with your finger: if the coating melts away, it is fat bloom.

Sugar bloom is different in both cause and texture. It appears as a grainy, dusty coating on chocolate, often with speckled or blotchy patches.

1. Humidity exposure: Sugar is hygroscopic, meaning it absorbs moisture from the air. In humid conditions, moisture dissolves sugar on the chocolate surface. As it evaporates, the sugar recrystallizes into larger crystals that scatter light and create a dull white film.
   
   

2. Condensation: Moving chocolate from a cold environment, like a refrigerator, into a warmer room causes condensation. The moisture triggers sugar bloom as it interacts with the sugar in the chocolate.
   
   

3. Refrigeration storage: Although refrigeration may seem like a way to prolong shelf life, the high humidity inside fridges almost always leads to sugar bloom.

Unlike fat bloom, sugar bloom feels rough to the touch. When rubbed, it does not melt.

Yes. Both fat bloom and sugar bloom are harmless. The main changes are aesthetic and textural. The flavor is usually unaffected, though bloomed chocolate may feel dry, crumbly, or grainy in the mouth.

For professional bakers, the appearance of bloom can impact customer perception. Bloomed chocolate can still be repurposed for baking applications like brownies, cakes, or fillings where appearance is not an issue.

Cocoa butter is polymorphic, meaning it can crystallize into six different forms, known as Forms I through VI. Forms I through IV are unstable, soft, and melt too easily, which leaves chocolate with a dull or uneven appearance. Form V is the structure that chocolatiers aim for when tempering because it produces a glossy finish, a crisp snap, and a smooth melt on the tongue. Over time, even properly tempered chocolate can gradually transform into Form VI. This form is very stable but develops slowly, often over months, and it gives chocolate a streaky look with a crumbly texture. This shift toward Form VI is one of the main reasons fat bloom occurs during storage.

Maintaining chocolate in a stable state requires careful temperature control and proper tempering. This scientific foundation explains why even slight fluctuations in storage conditions can have visible results.

Preventing bloom is more effective than trying to fix it. While melted and re-tempered chocolate can be restored, for professional kitchens it is best to avoid bloom altogether. Here are proven methods:

Keep chocolate in a cool, dry environment between 60–68°F (16–20°C). Relative humidity should remain below 55 percent. This stable range keeps cocoa butter crystals from shifting and prevents moisture from interacting with sugar.

Moving chocolate quickly from hot to cold or cold to hot environments encourages both fat bloom and sugar bloom. Chocolate should be stored in spaces with consistent temperatures and handled carefully during transport.

Sealing chocolate in airtight packaging or containers prevents it from absorbing ambient moisture and odors. Cocoa butter is sensitive to surrounding aromas, so airtight storage not only prevents bloom but also preserves flavor integrity.

The refrigerator is cold and humid, creating ideal conditions for sugar bloom. Only refrigerate chocolate when absolutely necessary. If refrigeration cannot be avoided, wrap the chocolate tightly and allow it to return to room temperature while still sealed before opening. This prevents condensation from forming on the surface.

For manufacturers, chocolatiers, or bakers melting chocolate for products, tempering is essential. Proper tempering creates the stable crystalline structure that resists bloom. If chocolate is untempered, bloom can form almost immediately after setting.

Moisture is the primary cause of sugar bloom. Work in kitchens where humidity is kept below 55 percent. Air conditioning, dehumidifiers, or climate-controlled storage can all help reduce the risk.

Bloom cannot be reversed once it appears, but chocolate can often be restored for functional use. Melting and re-tempering will reincorporate cocoa butter into a stable crystalline structure. However, if the bloom is due to sugar crystallization, melting may cause the chocolate to seize. In these cases, bloomed chocolate is best used for baking applications where texture is less noticeable.

• Rotate stock: Use older chocolate first to minimize storage time.
  
  

• Ship carefully: If receiving chocolate shipments in warm weather, make sure deliveries are temperature controlled.
  
  

• Handle with dry tools: Any water that touches chocolate can cause seizing or bloom. Always keep utensils completely dry.
  
  

• Repurpose wisely: Bloomed chocolate works perfectly in ganache, sauces, or baked goods. Do not discard usable chocolate.

At Baker’s Authority, bulk and wholesale chocolate is stored under carefully controlled conditions to help prevent bloom before it reaches your kitchen. Our goal is to deliver chocolate with consistent performance for professional applications.

For bakeries, cafes, and restaurants, presentation matters as much as taste. A customer presented with truffles or pastries streaked with bloom may assume the product is old or inferior, even though it is safe and flavorful. Preventing bloom is therefore not just about science; it is about maintaining customer trust and brand reputation.

For wholesale buyers, knowing that chocolate is handled and stored correctly from supplier to kitchen makes all the difference. Baker’s Authority maintains quality controls to help professionals receive chocolate that looks and performs as intended.

Does chocolate bloom mean it has gone bad?

No. Bloom is a visual defect, not spoilage. The chocolate is still safe to consume.

Is bloomed chocolate mold?

No. Mold is fuzzy and often has an odor, while bloom is simply fat or sugar crystals.

Does bloom affect taste?

Usually no, though it may affect texture. Sugar bloom can create a grainy mouthfeel, while fat bloom can feel waxy.

Can bloom be prevented entirely?

While prevention is very effective, it requires careful control of temperature and humidity. Proper storage reduces bloom risk significantly.

Can bloomed chocolate still be used in baking?

Yes. Bloomed chocolate works well in recipes where it will be melted or combined with other ingredients.

Chocolate bloom is one of the most common issues professionals face when working with chocolate. Though it does not affect safety, it does impact appearance and texture, which makes prevention essential for commercial use.

By understanding the causes of fat bloom and sugar bloom, and applying best practices in storage, tempering, and handling, bakers and foodservice professionals can keep their chocolate glossy, smooth, and customer ready.

At Baker’s Authority, our bulk and wholesale chocolate offerings are carefully stored and shipped to maintain quality and performance. By starting with ingredients handled under the right conditions and applying proper techniques in your own kitchen, you can keep bloom at bay and deliver chocolate products that look as good as they taste.