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Fat bloom is a common occurrencewhen working with chocolate products.

It is a physical defect that appears duringstorage of chocolate and is characterized asa whitish layer on the outer surface (Fig-ure 1). Chocolate with fat bloom is not onlyvisually unappealing, but also impacts theflavor and textural qualities, which are im-portant determinants of consumer prefer-ence. The phenomenon is not fully under-stood, but research suggests there are manyfactors which may contribute to fat bloomformation such as poor tempering, mixtureof incompatible fats, disrupted coolingmethods, temperature fluctuations, storageconditions and abrasion or finger marking.

Fat bloom impacts all of us: manufactur-ers, suppliers and customers alike. It is im-portant to understand when and why it isoccurring to hone in on the problem andimplement a corrective action. Overall, fatbloom is inevitable, but once you under-stand the fundamentals you can prevent itfrom occurring prior to the end of shelf life.

CHOCOLATE STRUCTURE

Chocolate has a complex flavor profile andcompositional matrix consisting of sugar, co-coa particles and emulsifiers dispersed in acontinuous phase of cocoa butter (Figure 2).Cocoa butter is a polymorphic fat composedof three main triglycerides (tags). These

tags are the building blocks of a strong foun-dation. A tag molecule is composed of aglycerol backbone with three fatty acid chainslinked by ester bonds. This molecule is mostcommonly illustrated in a chair-like or tuning-fork formation. These tags can crystallize insix different polymorph formations (Forms I-VI), which have specific melting points. Poly-morph Form V is the ideal form to achievewhen working with chocolate. When cocoabutter is in this form, chocolate achievesmany favorable attributes such as a smooth,even melting, clean snap and nice gloss. Thiscan be accomplished by tempering.

Chocolate Fat BloomFat bloom is inevitable, but once you understand the fundamentals you can prevent it from occurring prior to the end of shelf life.

Melissa TisoncikBlommer Chocolate Company

Melissa Tisoncik isthe research and devel-opment manager –product developmentat Blommer Chocolatein the company’sChicago R&D team.Previously, she workedat the USDA labs.

The Manufacturing Confectioner • April 2013 65

Figure 1

Chocolate Fat Bloom

Figure 2

Molecular Chocolate Matrix

Envision that all the tag molecules areindividual and mobile when cocoa butteris in its liquid state at 120°F. As the massbegins to cool, crystals begin to form andeventually a crystalline lattice is created(Figure 3). If the tag molecules create adisorderly nonuniform stacking, fat bloomformation can occur in the finished choco-late product. This can be initiated by tem-perature fluctuations, improper applica-tion techniques, improper handling orprocessing failures when working withchocolate.

INVESTIGATING FAT BLOOM

It is important to ask the following ques-tions when investigating cause of bloom:

• How does fat bloom affect our product?• Where is it seen on the production line?• When do we see it occurring?• What is the cause?• What challenges do we experience while

working with chocolate prior to pro-duction, during production or postpro-duction?

Fat bloom can appear in many differentways, but the following case studies willgive you general guidelines to help deter-mine the root cause and answer the ques-tions posed above.

TYPES AND CAUSES OF FAT BLOOM

Extreme temperature fluctuations (postap-plication) The image in Figure 4 shows thatenvironmental handling conditions werenot ideal. In this case study, bloom has im-pacted the structural integrity of the choco-late product and completely deformed it.This is caused during transportation or dis-tribution, e.g., the shipping truck sitting attemperatures 5° to 10° above the meltingpoint of chocolate.

Dirty moulds (during application) Dirtymoulds can initiate fat bloom due to aresidue chocolate layer being left on the

mould that acts as seed or site of crystalnucleation for subsequent depositedchocolate. This newly deposited chocolatewill form surface bloom. Proper cleaningof moulds is essential.

Temper (during application) Figure 5 is agreat representation of improper temperthat caused fat bloom. Can you see thelayers formed? This indicates that in eachlayer the chocolate was already crystaliz-ing as it was deposited into the mould. It isimportant to note that the cross-sectionalview of a chocolate product can give in-sight to your bloom investigation as well.

Cooling (postapplication) Figure 6 revealsa common case of fat bloom found rightafter the cooling tunnel or on retail

Chocolate Fat Bloom

Dirty moulds caninitiate fat bloomdue to a residuechocolate layer

being left on themould that acts

as seed or site ofcrystal nucleation

for subsequentdepositedchocolate.

66 April 2013 • The Manufacturing Confectioner

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Figure 3

Cocoa Butter Solidifying Schematic

Figure 4

Extreme Temperature Fluctuations

Figure 5

Poor Tempering

shelves. This is due to improper cooling.

Chocolate is more susceptible to this type

of bloom if you have poor temper as well.

You must look at the cooling capacity andcheck the temper prior to moulding.

Temper/depositing (during application)This is a unique case of fat bloom (Fig-ure 7) which needs to be investigated fur-ther. At first glance, it appears to look likea milk/dark drops mixture; however, tak-ing a closer look, you can see the streakingin the individual drops. You can perform aquick visual and sensory analysis to testfor fat bloom. Looking at the cross- section(Figure 8), one can see that the dark dropon the bottom is very uniform whereasthe light drop on the top is very speckledand crumbly looking. The taste is also verydry, void of flavor and crumbly in themouth. When you melt down the drops,the color slide indicates the same colorchocolate. These tests helped draw theconclusion that this was not a mixture ofmilk and dark drops, but it was fat bloom.

Formulation (prior to application) If yousee extensive bloom (Figure 9) and youhave ruled out all environmental factorsand production as a factor that may causebloom, you need to look at the formula.There may be an inherit formulation issuethat caused the chocolate to bloom at aquicker rate when exposed to high heattemperatures. This type of bloom formswithin 2 to 4 weeks after depositing and iscaused by a mixture of incompatible fats.

Interaction with inclusions (postapplica-tion) Figure 10 reveals fat bloom forma-tion due to cocoa butter interacting withincompatible oils, such as peanut oil. Theseliquid oils will migrate into the chocolateshell by dissolving cocoa butter liquid frac-tions, then migrate to the surface and formbloom. It helps to create a thicker choco-late shell around the center to prevent in-vasive migration and bloom on the surfacefrom occurring too rapidly.

Fat bloom can develop at many differ-

Chocolate Fat Bloom

It helps to create athicker chocolateshell around thecenter to preventinvasive migrationand bloom on thesurface fromoccurring toorapidly.

The Manufacturing Confectioner • April 2013 67

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Figure 6

Insufficient Cooling

Figure 7

Poor Tempering/Depositing Problems

Figure 8

Visual/SensoryAnalysis of Bloom

Wet slide test

Flavor/texture test

Figure 9

Formulation Issue

Figure 10

Interaction with Inclusions

ent stages. The timeline in Figure 11 is anexcellent gauge to help identify the rootcause of bloom based on when it appearsthroughout production. Once identified,a corrective action can be taken, but thereare also various preventive methods youcan utilize to inhibit fat bloom formation.

PREVENTATIVE METHODS

Tempering

It is essential to understand that the subtle -ties in this time/temperature process canimpact your product further down the line.If chocolate is not properly tempered, theincorrect crystalline structure is formed,which in turn can lead to bloom. A greattest to check temper is using the Tricor tem-permeter instrument. It is a quick methodfor operators to use on the line. The easyreadouts are translated into a number in-dicating good, great or need to retemper.

Knowledgeable Formulation

During formulation it is important to thinkabout the end application and how thechocolate will function. You must considerthe other fats in the final formulation andweigh the risk of incompatibility. Com-bining cocoa butter and a lauric fat such aspalm oil or coconut oil will promoteblooming and result in a soft texture dueto their eutectic effect. A good rule ofthumb: a maximum of 5 percent cocoabutter or lauric oil on a total fat basis can

be added to a lauric oil-based or a cocoabutter-based product respectively. Otherproducts used in final formulations withchocolate are nut oils (enrobed nuts), co-conut oil (meltaways) and soybean oil (liq-uid chips). Creating a barrier between thetwo incompatible fats is another key ideato consider. A great example of strategiclayering is seen in candy bar products,where sugar caramels create a barrier be-tween the nuts and the enrobed chocolatelayer. Also, a common ingredient added toinhibit bloom (within the standard of iden-tity for chocolate) is milk fat. The mediumchain fatty acids in milk fat can interactwith cocoa butter structure to prevent mi-gration and bloom.

Proper Storage

This is something we can try to controlwhile transporting chocolate. Proper stor-age, whether it be postproduction, ware-house, distribution, customer end or retailshelving, is essential to prevent bloom fromoccurring before the shelf life expires. Atthis point, chocolate is most susceptible totemperature fluctuations. The best condi-tions for chocolate storage are a controlledenvironment at room temperature and 40to 60 percent relative humidity.

CONCLUSION

Currently, there is ongoing research in in-dustry and academia which aims to un-derstand fat bloom phenomenon in choco-late. Some studies suggest that ingredientssuch as emulsifiers, seeding agents or evenfruit juices can help inhibit bloom. Fatbloom will naturally occur after a long pe-riod of time (~2 years), but if we aim totruly understand and investigate how itmay occur, we can minimize or prevent it,thus producing the best possible choco-late product. n

Chocolate Fat Bloom

Combining cocoabutter and a lauric

fat such as palm oilor coconut oil willpromote bloomingand result in a softtexture due to their

eutectic effect.

68 April 2013 • The Manufacturing Confectioner

Bloom can occur at different times and for differ-ent reasons prior to, during or postapplication.1. Immediate: within 12-28 hours2. Intermediate: 1-2 weeks3. Long term: 3-8 weeks

Figure 11

Timeline Gauge for Bloomed Product

Presented at the AACT National Technical Seminar