• Fat bloom can be initiated by dirty mould from the residue left by previously deposited chocolate which serves as seed or site of crystal nucleation for the subsequent deposited chocolate.
• Surface bloom is then formed by the newly deposited chocolate. Hence, proper cleaning of moulds is essential.

Figure 1.1 The mould is dirty and contain residual chocolate

• Tempering chocolate can be in the form of the heating, stirring, and cooling steps that stabilise the cocoa butter (fat) crystals which assure the chocolate to dry shiny and hard and breaks with a snap instead of giving grey or streaky appearances with a soft cakey texture (Medrich & Lamotte, 2015).
• Untempered chocolate will bloom after a short period of time because the cocoa butter has crystallised into less stable polymorphic forms which will recrystallize into more stable polymorphs. During the process, fat migrates to the surface and crystallises as a fine haze which lightens the chocolate colour and may also appear as visible, white or pale specks (Talbot, 2009).
• Under-tempered chocolate: dull and blotchy, lacking its desired gloss (Talbot, 2009).
• Over-tempered chocolate: poor gloss, since it often has fewer larger crystals and thus give rise to coarser structure in the chocolate, with the resulting dullness (Talbot, 2009).
• The glossy nature of well-tempered chocolate is due to the fine crystals produced during cooling after tempering, when the cocoa butter is in the correct polymorph (Talbot, 2009).

Figure 1.2 Improper temper leads to formation of multiple layers in cross-sectional view due to crystallization of chocolate deposited into the mold

• Cooling capacity and temper prior to moulding are essential.

Figure 1.3 Fat bloom found right after the cooling tunnel or on retail shelves due to improper cooling

• After preclude all the possible environmental and production factors, formulation can be the reason causing extensive fat bloom.
• There may be an inherit formulation issue that is causing the chocolate to bloom at a quicker rate when exposed to high heat temperatures. This type of bloom forms within 2 to 4 weeks after depositing and is caused by a mixture of incompatible fats.

Figure 1.4 Extensive fat bloom

• Fat bloom will also take place when cocoa butter interacts with incompatible oils, such as peanut oil.
• These liquid oils will migrate into the chocolate shell by dissolving cocoa butter liquid fractions, then migrate to the surface and form bloom.

Figure 1.5 Fat bloom when cocoa butter meets with incompatible oils

• This is caused during transportation or distribution, e.g., the shipping truck is at temperatures of 5° to 10° above the melting point of chocolate.

Figure 1.6 Appearance of chocolate when environmental handling conditions were not ideal

• Practically, every chocolate mass, each production line, and each chocolate product have their own optimal temper, specific tempering conditions for different combinations of milk fat and cocoa butter must be determined, to a larger extent, by trial and error (Garti & Widlak, 2012).
• A great test to check temper is using the temper meter instrument. It is a quick method for operators to use on the line. The easy readouts are translated into a number indicating good, great or need to retemper.

• Other fats compound in the final formulation must be considered and evaluates the risk of imcompatibility.
• For instance, combination of cocoa butter and lauric fat such as palm oil or coconut oil will promote blooming and exhibit softer texture due to their eutectic effect.
• Creating a barrier between the two incompatible fats is another fundamental idea to consider, e.g. candy bar products, where sugar caramels build up a barrier between the nuts and the enrobed chocolate layer.
• On the other hand, milk fat is a common ingredient added to chocolate product as it regulates the hardness of cocoa butter through its effect on phase behaviour and aids to prevent fat bloom during storage (Garti & Widlak, 2012).

• Proper storage, whether it be postproduction, warehouse, distribution, customer end or retail shelving, is essential to prevent bloom from occurring before the shelf life expires.
• At this point, chocolate is most susceptible to temperature fluctuations. The best conditions for chocolate storage are a controlled environment at room temperature and 40-60% relative humidity.