High-tech solutions for cocoa processing

Cocoa powder is the key ingredient in many chocolate-based foodstuffs and beverages that are enjoyed by millions of people around the world. In fact, over 5 million tons of cocoa beans are used globally to make cocoa powder each year. The process of producing cocoa powder and associated end products is a complex one, ranging from the pre-cleaning, pressing and alkalisation of cocoa nibs to the micronising, lecithinising and instant agglomeration of cocoa powder. The Hosokawa Group – leading experts in powder processing technology – offer comprehensive know-how and high-tech solutions to support customers every step of the way.

All chocolate-based products, whether chocolate bars, drinks, spreads or pralines, are made using cocoa powder that has been produced from cocoa beans grown in areas around the equator. Some of the main producing countries are Ivory Coast, Ghana, Indonesia, Nigeria and Cameroon. After harvesting, the pods are hacked open to expose the beans. The pulp and seeds are then left to dry in the sun. As the pulp ferments, it liquifies and trickles away leaving just the beans behind. After further treatment, the dried beans are shipped to processors and manufacturers worldwide to be turned into cocoa powder and chocolate-based products. A typical pod contains 30 to 40 beans, and up to 600 dried beans are needed to make 1 kg of chocolate.

From cocoa beans to end products

After being pre-cleaned and roasted, the beans are cracked and then undergo a process called 'winnowing' to separate the pieces of beans (called 'nibs') from the shells. The Hosokawa Group offers a full range of high-performance machines and systems for use in the subsequent steps of the process to produce cocoa powder and associated end products.

Starting with the nibs

First of all, it is necessary to pre-clean the cacao nibs. This can be done using the ZigZag classifier from Hosokawa Alpine. Next, batches of cacao nibs or 'broken nibs' are sterilised and homogenised ready for further processing. Hosokawa Micron's Conical Paddle Mixer (CPM) is a high-quality and efficient atmospheric vertical paddle mixer that is very popular for sterilisation and homogenisation in the traditionally no-nonsense, cost-conscious cocoa industry.

Conical Paddle Mixer (CPM) for sterilisation and homogenisation of cocoa nibs

Next, the cacao nibs are alkalised to give them a better colour and milder taste in line with the end product requirements. For this process, Hosokawa Micron has designed the robust Conical Paddle Dryer (CPD) to achieve gentle yet accurate mixing even under the harsh conditions of an alkalisation process. This is possible thanks to the low friction of the single-shaft paddle rotor, combined with a well-thought-out vessel design which results in a homogeneous temperature and composition profile from top to bottom.

Cocoa press cake

After alkalisation, the nibs are roasted and wet-milled into cocoa liquor: cocoa particles suspended in cocoa butter. The cocoa butter is then pressed, which separates it into two basic components: liquid cocoa butter and cocoa press cake, which is the base component for cocoa powder. The resulting solid discs of cocoa press cake must first be pre-broken before they can be micronised into cocoa powder. Hosokawa Micron has developed a robust, reliable and low-maintenance Prebreaker for the coarse size reduction of cocoa press cake prior to fine-micronising and subsequent processing.

Cocoa powder

Once the cocoa press cake has been pre-broken, there are various options to modify the resulting cocoa powder into different finished qualities for use in end products. When used in chocolate-based confectionery products, for example, the particle size of the cocoa powder affects the so-called 'mouthfeel'. In other words, this has a significant impact on the perceived quality of the product. The Hosokawa Alpine Classifier Mill (ACM) has been optimised for the specific needs of the cocoa powder market and can micronise the pre-broken cocoa cake into ultra-fine particles of 99.5% < 75 microns or finer to achieve the optimal mouthfeel.

ACM-150 Alpine Classifier Mill for micronising cocoa

To smoothly process high-fat cocoa up to 26% fat content, the mill is designed with a straight outlet and a coaxial bearing to maintain an unhindered product outflow and significantly reduce clogging. Furthermore, to maximise the lifetime of the equipment, the ACM contains various wear-protected components for extra protection against the abrasive residues in the cocoa. The ACM can even be used for milling cocoa shells as well as for milling instant beverages and chocolate crumb.

Batch mixing

Batch mixing is often an important process step in the production of all kinds of cocoa-based foodstuffs and beverages. Hosokawa Micron's Nauta® conical screw mixer is well-known in the world of cocoa processing as a robust and versatile mixing solution for low-intensity mixing. It is very well suited for homogenising cocoa powders with a wide variety of product characteristics. The Nauta mixer is a highly efficient, convective mixer. Its mixing screw is suspended from an orbital arm and rotates along the inner vessel wall. This guarantees the highest level of mixing accuracy and process flexibility without product distortion.

Lecithinising

Lecithinising is a key step in the manufacture of end products such as cocoa-based drinks and pastes. In this process, (fatty) cocoa powder particles are coated with lecithin to increases their solubility in aqueous solutions. Hosokawa Micron's Vitomix ribbon screw mixer can be used to lecithinise cocoa powder in a batch operation. The design of the two conical mixing screws creates a fluidised bed in the upper part of the mixer cone that is perfect for adding liquids.

Instant agglomeration

If a continuous process is preferred, the cocoa powder can be lecithinised in Hosokawa Micron's Flexomix. In a process of high-impact continuous agglomeration, the Flexomix mixes the particles with sugar and dairy components to create homogeneous porous agglomerates that are instantly soluble thanks to their narrow particle size distribution.

The Flexomix is a compact vertical high-speed mixer with typical residence times of just a few seconds, and the innovative design comprises a flexible mixing chamber which includes an external roller massage system for self-cleaning. The agglomeration process can be optimised by changing various process parameters such as rotor speed, number and angle of the paddles and/or liquid percentage. This enables the user to adapt the process to the quality required for each application, from consumer products (low density) to vending-machine products (high density).

Flexomix for instant agglomeration of cocoa powder

One-stop shop for cocoa industry processing technology

With 120 years of experience, the Hosokawa Group offers a wide range of innovative powder processing technology and customised solutions from a single source. The group has several research and technology centres across Europe, Japan and the USA.

The test centre located at the Hosokawa Micron manufacturing facility in Doetinchem, the Netherlands, comprises more than 2,000m² and is fitted with 30 machines. The knowledge from the group's technical experts is combined as necessary for each project, allowing customers all over the world to benefit from a one-stop shop and a single point of contact for any issues related to the processing of cocoa powder and cocoa based products.