Milk Chocolate Applications — Maintaining Quality and Solving Problems

William Dyer Blommer Chocolate Company

“quality” and “problem” as they apply to hocolate, to some consumers, is the Dyer joined Blommer Creward. It’s the ultimate indul- enjoying and using chocolate.As we’ll see, Chocolate Company in gence — truly a feel-good pacifier and it depends on whom you ask. 1996. He provides tech- In regard to quality, when you ask con- nical support in the use part, as some chocoholics claim, of an of chocolate, com- important food group. sumers, they’ll tell you their criteria are pounds and alkalized What’s not to love about chocolate? It appearance of the product, wonderful cocoa powders in a has a wonderful fragrance, delicious taste rich flavor, good eating quality, mouthfeel variety of applications. and smooth mouthfeel. But as appealing as and value. Dyer worked at Gill and Duffus Products, then chocolate is, it brings special quality and A candy manufacturer will cite all of the joined Durkee Indus- manufacturing challenges for producers of above and add a few others.These include trial Foods; through confections and baked goods. Why? the suitability of the chocolate in a partic- acquisition, Dyer was Because chocolate has some unique behav- ular application, the nature of ingredients transferred to Loders Croklaan. While there iors that need to be understood and man- to be combined and the cost and avail- he developed technical aged in order to produce the best prod- ability of the ingredients. Last, but not presentations to provide ucts possible. least, there’s shelf life and stability of the education about ingre- In this paper we’ll review some of the finished product. dient applications. challenges of chocolate issues from the per- The chocolate manufacturer must be spective of the “real world,” rather than from able to meet all of the candy manufactur- academic experiences and experiments.We ers’ needs and expectations, and duplicate will look at special considerations in select- them consistently batch after batch. Both ing and using chocolate.We’ll see how prob- the manufacturer of the chocolate and the lems occur when we incorrectly identify candy producer view these considerations process problems and their solutions. And, of quality in practical terms. we’ll evaluate some storage issues. Of course, some criteria are common to But first, we need to define the words the consumer, candy manufacturers and William Dyer

52nd P.M.C.A. Production Conference, 1998 137 Milk Chocolate Applications

We must chocolate producers.These are the appear- in the chocolate recipe result in chocolates understand the ance, rich flavor and the structural integri- with richer flavor, but the chocolate user must interaction of a ty of the confection. In this business, of keep in mind that high milk content in the chocolate course, we translate these attributes into chocolate will result in a higher percentage of coating with the our own, more familiar terms. milk fat in the total fat phase. The emphasis confection’s • Where the consumer says “appearance,” here is on percentage of milk fat because we center during we may say “initial gloss,” “gloss reten- know that trace amounts of milk fat in choco- tion” and “bloom stability.” manufacturing, late prevent bloom in finished products, but • Rich flavor becomes the “flavor release shipping and higher levels of milk fat will result in limiting of the product.” shelf life. functional attributes of chocolate. • And, structural integrity means the touch Cocoa butter’s sensitivity to high levels of stability of the product, as well as its milk fat results in slow crystallization dur- hardness and heat resistance during dis- tribution to points-of-sale. ing tempering and produces softer choco- Now that we have defined the attributes of lates. Part of this incompatibility stems from quality, the definition of problems related to the differences in melting characteristics. chocolate application is easier. When we Milk fat is a liquid and cocoa butter is a see any of the above quality criteria out of solid at room temperature (70ºF). synch, or even starting to drift from the We can get a perspective on tempera- norm, we know there’s a problem. ture response of the mixtures of cocoa butter and milk fat from the Jensen cool- KEY FACTORS FOR SUCCESS ing curves (Figure 1). Notice as the milk In producing confections there are four fat increases, the crystal-initiating tem- specific areas where problems occur. The perature decreases and the crystallization first is the selection of the type of choco- rate decreases. late. This is often the primary source of This has important consequences for the difficulties. Here, the level of milk fat in the candy producer, because mixtures that con- chocolate is important. tain both will crystallize at a much slower The second critical issue is chocolate rate. The higher the milk fat content, the application, including storage and handling. longer the tempering time. These mixtures This includes temperature concerns. The also require lower tempering temperatures. third is understanding oil migration, its A slow crystallization rate also means that negative effects and how to avoid or min- the product needs a longer dwell time in imize them.We must understand the inter- the cooling tunnel. action of a chocolate coating with the con- There is another concern regarding the fection’s center during manufacturing, use of milk chocolate in a product which shipping and shelf life. And, finally, there may have nut oil or another type of oil in the are issues associated with the storage of center. The stress on the cocoa butter from finished products. We’ll discuss each in the milk fat, coupled with the interaction some detail. with other fats in the center, will drastically limit the shelf life. The solution? Start with CHOCOLATE SELECTION a lower milk fat milk chocolate. CONSIDERATIONS Current standards allow chocolate suppliers Form to produce milk chocolate with a minimum As I’ve just noted, the type of chocolate is of 10 percent chocolate liquor, 3.39 percent important. But its form is, too. Chocolate milk fat and 12 percent milk solids. is available from the manufacturer in three Higher levels of milk powder and crumb different forms:

138 52nd P.M.C.A. Production Conference, 1998 Milk Chocolate Applications

ity. (Chocolate melters require 15 rpm.) The critical Cooling Curves of Cocoa Butter and Butter Fat Once most of the chocolate melts, we factor in using recommend holding the temperature at any chocolate 88ºF or 90ºF, depending on the type of 1 that is already 3 chocolate. Dark chocolates can be used at tempered is 2 90ºF, but milk chocolates, because of the milk fat, should be used at 88ºF. converting the 5 This approach allows for some beta crys- solid chocolate 4 tals to be left intact. This is important into liquid because beta crystals replicate during the without losing 6 cooling process — a coating response that the temper state. is essential in order to achieve a stable

∆t crystalline form in the chocolate.

Temperature 1. 100% CB 4. 90% CB 10% BF 2. 100% Softer CB 5. 85% CB 15% BF The temperature of stored bulk liquid 3. 95% CB 5% BF 6. 80% CB 20% BF chocolate is critical, especially for milk Figure 1 chocolate. Its ideal storage temperature is

• Liquid, which requires tempering 115º–120ºF. • Tempered and molded 10 lb blocks Exposure to higher temperatures for an • Tempered wafer discs extended period of time will cause the milk Each requires special handling and stor- proteins in chocolate to denature. This age from the time the chocolate is delivered results in grainy texture, off-flavors and by the supplier until it is incorporated into higher viscosity. Thus, monitoring and finished goods. maintaining constant temperatures in the Liquid Chocolate. Liquid chocolate should right range is very important. be stored in vertical or horizontal tanks Obviously, the heat source and the con- with agitation. The agitators should be set sistency of heat distribution is also important. on a timer, so that the chocolate is stirred For example, tanks in hot rooms tend to dis- intermittently — at least 10 to 15 minutes tribute heat more evenly than individually every hour. Keep in mind that when the heated tanks. Jacketed tanks do have their chocolate is being used, the agitator must merits, provided the jackets are designed to be on at all times.The agitation rate for ver- distribute heat evenly and consistently.The tical mixers is 17–18 rpm. Horizontal mix- source of heat, such as hot water in the jack- ers require 13–14 rpm. These are all tank et, must be carefully monitored to guaran- manufacturers’ guidelines. tee that proper amount of heat is transmit- Solid Chocolate. The critical factor in using ted to the stored chocolate at all times. any chocolate that is already tempered is Allowing cold drafts to blow on ther- converting the solid chocolate into liquid mostats or other heat-regulating sensors without losing the temper state. This is can create problems, because this can trig- achieved by warming solid chunks of tem- ger the heating in the hot room or heating pered chocolate or tempered chocolate medium in a jacketed vessel. The result is wafer disks to 90ºF, so that 85–90 percent that more heat than needed reaches a of the cocoa butter melts. Gentle agitation product that is heat sensitive. is needed during melting and cooling to Excess heat applied very briefly may not maintain a uniform temperature profile result in the degradation of the chocolate, and to help to achieve a workable viscos- but excess heat, even by a few degrees, can

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Allowing cold stress the tempering machine, resulting in of the history and current status of tem- drafts to blow on poorly tempered chocolate outputs. This peratures in all production phases from the thermostats or is especially true if the heat exchanger for holding tank to the enrober. the tempering unit is already running at This data can be achieved by — other heat- maximum capacity and can’t cope with the • conducting hourly checks at key points regulating increased heat load. in the process, and sensors can It should come as no surprise that heat • installing temperature sensors in the create problems. issues can have a major impact on quality line, including return loops, with cir- and on the bottom line, even if excessive cular charts to show the status (past and present) of hot rooms and of heat- heat occurs for just a matter of minutes. In ing devices for jacketed tanks. This three to five minutes, a continuous tem- approach means that plant personnel pering unit, depending on its size, can tem- can easily monitor temperature trends, per from 50 pounds to more than 300 so the maintenance crew can quickly pounds of chocolate.At 25 percent choco- identify the source of the problem. late pickup at the enrober, that translates The bottom line is that the more tem- to 200–1,200 pounds of finished goods, or perature information we can generate at roughly half a pallet of finished goods for key locations on an hourly basis, the bet- a line with higher throughput rates. If the ter control we can have of the status of quality of the chocolate has been com- the process. Having accumulated histor- promised, that can prove expensive. Pro- ical temperature data helps the mainte- duction line personnel find the problem nance or process engineers answer two tough to diagnose because the system may key questions: be back to normal by the time the product • Is the heat source delivering the required reaches the end of the production line and heat consistently within a reasonable is clearly off-spec. range of fluctuation? Here’s a common scenario. Let’s sup- • Is the cooling source removing the heat consistently within a reasonable range of pose that the chocolate in the enrober fluctuation? overheated briefly, but the system is now This same information can be helpful over back to normal.The enrober operator gets the course of the entire year, because it a complaint from the packaging operator, reveals seasonal trends. For instance, plant who reports that the bars are not shiny. personnel can spot the overload of water The finished product looks dull. tower cooling capacities in the hot sum- The problem with excess heat occurred mer months. Obviously, this offers tremen- some 15 minutes earlier. It lasted just three dous advantages when demand from var- to five minutes. By this time, the temper- ious cooling systems is high and heat ing and enrober operating parameters do exchanger systems for the tempering unit not need any adjustments. They are oper- and cooling tunnel are all consolidated into ating normally again. But, the enrober one common system. operator forges ahead and tries to fine- We suggest monitoring the following: tune them.The result? A constant jockey- • The temperature and feed rate of untem- ing that greatly affects quality over the pered chocolate feeding the tempering course of the production for this entire machine batch of chocolate. • The temperature profiles of the choco- How do you prevent this from happen- late in the tempering machine ing? Rather than leaving process temper- • The status of the cooling media for the ature decisions up to the operator, we sug- tempering machine gest having available a thorough knowledge • The dwell time in the cooling tunnel

140 52nd P.M.C.A. Production Conference, 1998 Milk Chocolate Applications

• The cooling tunnel temperature profile, They suggest that the quality of these prod- Products coming including the amount of air and loca- ucts depends on how well they are cooled, out of the tions where air is blown not just on how long they are cooled. A cooling tunnel • The tunnel temperature when the tunnel good understanding of the capability and are not really is running at full capacity the limitations of your tunnel’s perfor- This information allows process personnel mance is critical. Chocolate users must rec- finished for at to make quick decisions to prevent pro- ognize this before they release products least another 24 duction problems or at least to minimize for distribution. Otherwise, they may run hours. their occurrence. into problems with products that have lack OTHER PROCESS ISSUES of gloss or poor touch stability. Eventual- ly this results in bloom. There are other production issues that we We suggest that you talk to your tunnel must also keep in mind. These involve suppliers for technical help to determine enrobers and cooling tunnels. the exact temperature at specific tunnel Enrobers locations. Sollich, a cooling tunnel manu- Enrobers can be a source of product qual- facturer for the confectionery industry, ity problems, because they trap crumbs, uses a temperature-sensing device (Figure nut pieces and high-moisture-containing 2) called Scorpion Sensor to monitor tem- tails from centers. These can wreak havoc peratures at specific locations of the tun- in chocolate. If they are left in contact with nel. This instrument works as a diagnos- chocolate for an extended period of time, tic tool and it is designed to measure they lead to softening of the chocolate and tunnel performance. This offers a wealth can have adverse effects on its flow prop- of useful data. erties, so they must be screened and OIL MIGRATION removed quickly. Now let’s look at the next critical factor— Some of you are probably saying, “Our the interaction between chocolate and fat- process is okay. We have crumb- and tail- based centers or other types of centers that screening devices designed in the chocolate promote oil migration during shelf life. return systems.” But if these are positioned Oil migration problems have been with after the detempering stage, you may still us ever since we began incorporating have a problem, because, by the time the nuts and nut oils in the centers of our chocolate reaches the screen, it has already candies and confections. We have devel- traveled through a pump where the crumb and tailpieces break into smaller pieces Cooling Tunnel Sensor and are further homogenized into the SENSOR BAR chocolate. So we recommend screening before the chocolate is subjected to a high sheer mixing or pumping stage. DATA LOGGER

Enrober manufacturers must take this Scorpion PERSONAL COMPUTER issue into consideration in designing new generation enrobers. THERMAL WALL BARRIER BRACKET PLOTTER OR PRINTER The Cooling Tunnel Previously published studies and presen- tations clearly indicate that products com- ing out of the cooling tunnel are not real- ly finished for at least another 24 hours. Figure 2

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Fully oped products that have gained great changes in the apparent flow properties of fractionated and consumer appeal. They taste great. But the filling. But, as with so many things, this hydrogenated we still have not developed technology to is just an illusion. keep the oil from migrating from the cen- As an illustration, let’s evaluate what hap- palm kernel oil ter into the coating. pens with pure peanut butter. It has more has been used We know that using fats that are not than 50 percent peanut oil and it is a free- in product compatible with cocoa butter in the centers flowing liquid mass at 85º–90ºF. When we centers with nut contributes to these problems. But, regard- add sugar, nonfat milk components, soy meat or nut oil less of the source of the oil, its behavior can flour and even cereal to the mixture, it with a great be traced to one fact: Fats that are not becomes thick. Its consistency leads us to degree of compatible with each other tend to pre- believe that the peanut oil is tied up nicely vent one another from going into the crys- in all of these nonfat components. Given success. These talline phase. Eventually these incompat- ideal conditions and machines, we might fats also provide ible fats will crystallize, but not into one even say it is extrudable. a sharp melting matrix. They crystallize separately, result- But here’s the reality: these non-fat com- profile. ing in a very poor crystalline matrix that ponents do absorb oil, but they do not hold allows oil migration. the oil.They act as wicking agents just like The loss of gloss during shelf life is one of paper toweling mops up oil spilled on the the early symptoms of oil migration. Even- kitchen counter. Oil is absorbed on one tually, this leads to a severe bloom and dis- end of the substrate and is released to the coloration of the product surface. It doesn’t other nonfat components that it touches. affect taste, but it upsets the consumer due And depending on the temperature to poor appearance and texture. conditions, the oil can travel. The higher Until some modern miracle occurs, we the temperature, the greater the oil need to accept the fact that oil migration migration rate. is inevitable. So what can we do? We can Powdered sugar also tends to give the slow down the rate of migration and help perception that it is preventing the oil from increase shelf life. In essence, we’re simply migrating. What the sugar particles are reducing the consequences of the detri- really doing is using the oil for lubrication mental effects of migration.There are sev- of each particle. This oil will start to move eral ways to do this. at higher temperatures, too. One is to use a chocolate coating that is This phenomenon has been demon- well tempered to provide the best crys- strated very clearly by Wootton and his talline matrix possible. This acts as an oil co-workers from Australia. In their work migration barrier. We will discuss this in (Figures 3 and 4), icing sugar and peanut detail in a moment when we talk about oil mixtures were held next to each other, barrier coatings. enabling the oil to migrate between them. Current industry practice is to add non- One mixture had 33.3 percent peanut oil fat ingredients such as milk solids, sugar, in sugar and the other had 18.8 percent carbohydrates and proteins such as soy peanut oil in sugar. Both were stored at flour, peanut flour and cereal to tie up the 15ºC and 30ºC and the oil content of both oil. But despite these efforts and consid- was determined at intervals of 2 weeks. erable ingenuity, these approaches are just The effect observed in this test was solely stopgap measures that have not effective- due to temperature and not due to differ- ly solved the problem. The non-fat com- ences in solid fat content, since peanut oil ponents mentioned above do not work, contains no solid fat. The tests show that but we think they do, because we see migration takes place more slowly at the

142 52nd P.M.C.A. Production Conference, 1998 Milk Chocolate Applications lower temperature, even though the of success. These fats also provide a sharp The goal is to amount of liquid oil is the same.The graphs melting profile. They have good flavor have 50 percent show that the equilibrium oil content of release and work well at ideal chocolate- of crystallization 26 percent was reached quicker at 30°C. application temperatures. Keep in mind, occur before The conclusion is that we cannot control however, that palm kernel oils are not com- and during — oil migration with a nonfat component that patible with cocoa butter, so their appli- is used as a migration-slowing agent. cation is limited by: the concentration of not after — nut oil; process time; and process temper- depositing. Migration-retarding Fat atures.This system offers limited shelf life Fats and oils are quite stable in a solid because palm kernel oil is highly incom- state. They move from areas of higher to patible with cocoa butter. lower concentrations only when they are Fractionated domestic oils made with in a liquid state. For this reason, oil migra- palm, soybean and cottonseed oils are tion control can be accomplished by using also useful in managing oil migration oils that can stay in crystalline form. The problems. These oils provide the ideal type and size of the crystal and its melting crystalline matrix to hold the oil, because point are critical factors, but using high cocoa butter is more compatible with melting point, fully hydrogenated veg- them than it is with palm kernel oil. The etable oils derived from soybean, cotton- limiting factor here is that these fats do not seed and canola isn’t the answer. These impart a waxy mouthfeel, do not release fla- Fat Migration — Model Studies vor and do not behave as well as other fats at ideal chocolate-application tempera- tures because they become highly viscous.

What Works? 33.3% peanut oil 18.8% peanut oil Fully fractionated and hydrogenated palm in sugar in sugar kernel oil has been used in product centers with nut meat or nut oil with a great degree Figure 3

Effect of Temperature on Fat Migration 15ûC Storage 30ûC Storage % oil % oil 34 34 B B

B 30 30 B B B B B B B B B

26 26 J J J J J J 22 22 J J J J J J 18 18 02468 02468 Weeks Weeks B High Oil Side J Low Oil Side B High Oil Side J Low Oil Side

Wootton et al, Rev. Int. Choc. 26 (1971) 266-271 Figure 4

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The critical release flavor as quickly as fractionated er the nut oil ratio, the longer it will take factor is the set and hydrogenated palm kernel oils. The to induce crystallization. Rapid, controlled point one exception to this is the fractionated cooling of the filling will result in the for- domestic fats that are made with a high- mation of a fat matrix with smaller crystals. temperature of er ratio of cottonseed or palm oils. The This is the same technique used in the the total fat unique fatty acid ratios found in these oils manufacture of bakery shortenings. phase of the tend to provide a better crystalline matrix In addition to precrystallizing, the dis- filling. to hold the liquid oil. tance between the cooling and precrys- tallizing vessel and the depositor hopper Forming the Fat Matrix is important. The matrix formed in the Several other considerations are important filling will be destroyed if the filling is for success in selecting the correct fat to subjected to high sheer mixing, agitation retard fat migration. The melting point or high sheer pumping. So, the longer the and melting profile help us estimate the distance between the vessel and the set point of the fat matrix in which the depositor, the greater the destruction of oil is going to be held. One also needs to the fat matrix. Of course, this completely determine where in the production defeats the purpose of adding the matrix- process to promote the formation of the forming fat, because the oil will no longer fat matrix. This is important because it be bound by the fat matrix and the matrix drives other decisions, too. won’t re-form in a highly desirable small- Here’s an example to help illustrate crystalline structure. some of these complex issues. To avoid this problem, locate the cooling Let’s assume that one is producing a vessel directly above the hopper, so that candy with a center high in oil. A suitable cooled filling can be discharged by gravity matrix-forming fat will be part of the ingre- feed, rather than by pumping. (Figure 5). dients in the filling. Experimental samples It’s also important that the filling in the suggest that the center is stable, which depositor hopper be at the ideal viscosity means longer shelf life. Sensory tests indi- at application temperature. This can be cate that flavor release is acceptable. You accomplished by fine tuning the ratio of want to scale this product up to full pro- fats in the total fat phase of the filling. duction using the depositor in a shell-mold- Finally, plan to use the filling in the ing operation. hopper quickly, especially if there are agi- The filling must be properly cooled and tator paddles in the hopper. As already precrystallized before it is transferred to the noted, excessive agitation in the hopper depositor hopper. The goal is to have 50 can lead to severe destruction of the fat percent of crystallization occur before and matrix in the filling. during — not after — depositing. Precrys- tallization produces small seed crystals that Barrier Coatings assure proper crystallization later in the Oil migration can also be managed by process. This is important because small using barrier coating technology. crystals are ideal for an oil-holding matrix. We create a barrier between the choco- Otherwise, a product with a high concen- late and the oil-rich center. Panning appli- tration of oil in the center would have a cations already use nonfat ingredients as a detrimental effect on the chocolate shell. barrier. Barrier solutions are made with The critical factor is the set point tem- one, or combinations of several, hydrocol- perature of the total fat phase of the fill- loids, such as gum arabic, gum acacia, mod- ing. This is determined by the ratio of the ified starch and dextrin in sugar solutions nut oil to the matrix-forming fat.The high- with specific total solids. Precoating oil-

144 52nd P.M.C.A. Production Conference, 1998 Milk Chocolate Applications rich centers (such as nuts and nutmeat- particles in a sand bed. Let’s say that 10 Oil migration containing centers) with gum solutions pounds of sand will hold 2 pounds of water. can also be made with gum acacia and sugar solutions, If that sand is ground to a finer powder, managed by can help prevent the nut oil from migrat- that same 10 pounds of sand will hold 4 using barrier ing into the chocolate. pounds or more of water, depending on The confectionery industry needs to the size of sand particles and the particle coating explore further to see if we can expand size distribution. Similarly, cocoa butter technology. this technology into other confectionery with the smallest crystals will result in a applications. For example, the use of a non- tighter matrix, producing a fine granular fat barrier system in enrobing operations structure. It holds more oil and can be use- or spraying centers for products that can’t ful as a barrier to minimize oil migration. be panned would be interesting. Perhaps This stronger structural integrity also means the benefits would be similar to those seen that it is more heat stable. in panned goods. Some have had success using a vegetable STORAGE ISSUES fat in a barrier coating. The criteria for fat Storage of finished products offers chal- selection in barrier coating are similar to lenges because of many variables.We must those in the fat matrix approach. The veg- consider the centers and their composi- etable fat used in the barrier coating must tion, the thickness of the chocolate coating be compatible with cocoa butter, must be and the presence of nuts and nutmeats in able to retard fat migration and, of course, the product. must have good eating qualities.These veg- We also handle molded and enrobed etable fat barrier coatings can also be used products differently. Here are some gen- as bottomers where oil migration due to eralized considerations: gravity is a concern. Heat. When products exit the cooling The chocolate coating used as a barrier tunnel, we must recognize that the cocoa to minimize oil migration must be properly butter in the chocolate has not complete- tempered and cooled. One can produce a ly crystallized. In fact, previous work has chocolate with a very fine granular struc- suggested that the amount of cocoa butter ture if one starts with well-tempered chocolate that has not been subjected to Critical Process Considerations: Pre-crystallizing Vessel and Depositor too many heating and cooling cycles prior to and after application. One must also 1 cool it under optimum tunnel conditions. Why? Because well-controlled temper- 2 ing and cooling produces crystallization that yields a large number of very small 3 beta crystals. These crystals form into a tighter crystalline matrix that is hard and has the ability to retard fat migration. 4 Another way to look at this crystalliza- 5 tion behavior is to recognize that many smaller crystals have greater surface area than fewer large crystals, so more liquid 1. Filling Feed Line 4. Depositor Hopper uncrystallized cocoa butter and milk fat 2. Pre-crystallizing Vessel 5. Agitator Paddles 3. Temperature Controls can be entrenched efficiently in the matrix. Here’s how that works. Visualize sand Figure 5

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The use of a Solid Fat Content of Cocoa Butter and Butter Fat Blends nonfat barrier 100% 95% Cocoa 90% Cocoa 85% Cocoa 80% Cocoa 100% Cocoa Butter Butter Butter Butter Butter system in Butter 5% Butter Oil 10% Butter Oil 15% Butter Oil 20% Butter Oil Oil SFC @ enrobing 50°F/10°C 84.2 80.1 75.2 73.8 72.8 35.8 operations or 70°F/21.1°C 70.0 62.5 50.0 37.5 30.4 10.8 80°F/26.7°C 61.7 53.8 42.2 24.8 14.1 8.0 spraying centers 92°F/33.3°C 9.2 7.1 5.8 3.6 2.9 for products that Source: Aarhus Inc. Figure 6 can’t be panned would be not crystallized is 10 percent or more and transfer and don’t shrinkwrap pallets for interesting. it can take 24 hours or more for a complete at least 24 hours, if possible. crystallization.This is more pronounced in Storage temperatures and humidity milk chocolate with higher milk fat content, should be based on the shelf life expected because milk fat depresses the solids pro- from the product. For longer shelf life use file.As seen in the sfc profile, it also delays lower temperature and lower humidity. C.D. the crystallization process (Figure 6). Barnett has detailed guidelines for opti- If crystallization is incomplete and still mum storage conditions for specific types of underway, the heat of crystallization is confectionery products. But even with this going to be released from the product. type of information, one must still use dis- Exposing products to temperatures high- cretion and design a storage protocol based er than 65ºF at this point will result in on experiments with your products. latent heat being trapped in the wrap- Odors. Chocolate can pick up odors, per, leading to disruption of cocoa but- especially when products are in storage ter crystal size and quality on the sur- for six months. This phenomenon occurs face of the product. because odors are more volatile than fla- Two things can happen at this point.The vors and tend to diffuse through packag- first is that the desirable small stable crys- ing materials, even ones that we would not tals that we’ve worked so hard to produce expect them to penetrate. So chocolate will melt.They will recrystallize into unde- products should be stored in warehouses sirable large crystals that yield a dull prod- dedicated to confectionery products only. uct. The beautiful gloss on the product Also, avoid storing non-mint and mint-fla- when it exited the cooling tunnel will no vored products close to one another. Final- longer be there. ly, use dry, odor-free pallets to avoid a pine The second problem is that, depending or woody smell. on the level of the heat stress to which the product is subjected, the quality of CONCLUSION the crystalline matrix will deteriorate to We’ve covered some of the most impor- a less stable beta prime form. This will tant criteria to remember during chocolate result in surface bloom within days of dis- production, chocolate application, stor- tribution. The solution to both problems age and delivery of the product to con- is to hold the products in a staging area for sumers.This is, of course, from a practical, at least 24 hours at 68ºF and 60 percent real world perspective and it is by no humidity to allow the fat matrix crystal- means exhaustive. lization to be complete before products First and foremost, chocolate manufac- are moved to a warehouse located out- turers must clearly understand the needs, side of the manufacturing facility. Addi- production constraints and cost constraints tionally, stack the boxes to promote heat of their customers — the chocolate users.

146 52nd P.M.C.A. Production Conference, 1998 Milk Chocolate Applications

First and Communications foremost, VENDOR USER chocolate TECHNICAL TECHNICAL manufacturers must clearly understand the

SALES AND PURCHASING needs, MARKETING production constraints and TIME

Figure 7 cost constraints of their Not all chocolate users have the same types meet the quality standards needed in the customers — of equipment, production layouts and flex- finished goods. the chocolate ibility to use different forms of chocolate, so We must understand, too, that the shelf users. the chocolate that is delivered must be flex- life of finished products depends not only ible enough to meet chocolate-user capa- on the type of chocolate used but also on bilities and facilities. how it is processed, applied and stored. Communication The overall goal is to slow down the To accomplish the mutual goals of the movement of fats and oils that are sensi- chocolate manufacturer and the chocolate tive to cocoa butter. Oil migration is a fact user, there’s one other recommendation of life. If you use milk chocolate high in that is essential — communication. milk fat in a product that has a high level You need a solid understanding of the of nut oil in the center, you can’t expect it final objectives of the project in order to to be shiny, bloom-free and hard after six optimize quality and cost. The chocolate months, but carefully selected, matrix- user must recognize the technical objectives forming fats can help manage this problem. and balance these with cost objectives to It is critical that we use the selected fat achieve optimum product performance. correctly. We can’t completely stop oil For this reason, solid communication migration, but with suitable matrix-form- among the technical and commercial groups ing fats, proper application parameters and from both the manufacturer and the user process design and procedures, we can slow of chocolate is a prerequisite. Toward that down the rate of migration and, as a result, end, I suggest a two phase/four group com- munication matrix (Figure 7). extend shelf life. The quality and level of communication REFERENCE among these four groups will determine 1Barnett C.D. The Science and Art of Candy how quickly and effectively the project Manufacturing. Magazines for Industry, Inc. objectives can be accomplished. 2Rosenberger H.L. Benefits and Risks Associated As we’ve seen, the chocolate user needs with Public Refrigerated Warehousing of Candy. PMCA Proceedings, 1994. to be aware of the many considerations in 3Minifie B.N. Chocolate, Cocoa, and Confec- storing, handling and processing the incom- tionery. ing chocolate, since not all chocolates are 4Kattenberg H.R. The Effect of Cocoa Butter on Chocolate Tempering and Bloom. PMCA created equal. One size does not fit all.We Proceedings, 1989. must recognize the characteristics of the 5Seguine E.S. Tempering, The Inside Story. incoming chocolate and select one that can PMCA Proceedings, 1991. ■

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