Publication from the Chocolate Review
by Samantha Madell




How chocolate is manufactured


Here's a challenge: examine the list of ingredients on any bar of fine chocolate. Cocoa solids are listed first, right? (Hint: if sugar is listed first, meaning that sugar is the principal ingredient, then what you've got is a sugary confection, not a fine chocolate).

"But wait!", you say. "The first ingredient listed on my bar of fine chocolate isn't cocoa solids, it's cacao (or cocoa mass, or just cocoa, or cocoa butter)". Well, OK. The point is that the one vital ingredient in all chocolate comes from the seed of the tree called Theobroma cacao, or, more commonly, cocoa. (The word Theobroma means "food of the gods" in Greek, while the word cacao is derived from the ancient Mesoamerican name for cocoa. The common name cocoa is thought to be an Anglicised version of the word cacao). But what exactly are cocoa solids? How are they obtained from the cocoa tree, and how are they transformed into chocolate?

Cocoa butter is solid at room temperature
Cocoa butter is solid at room temperature

The term "cocoa solids" refers to both nonfat cocoa solids, or NFCS (i.e. the brown stuff that gives chocolate its characteristic taste and colour), and cocoa butter (the relatively bland-tasting yellow vegetable fat obtained from cocoa beans). Cocoa butter is solid at room temperature, hence its inclusion in the category of cocoa solids.

Cocoa trees are native to South America, and they have a very long history of cultivation in Central America, but these days cocoa is grown in more than 40 countries located on or near the equator. Most of the countries that grow cocoa are very poor (Australia being one notable exception). Indeed, the poverty of cocoa growers is an important issue, all too often ignored or glossed over by people in the chocolate industry (here at ChocolateReview we're working to expose - and change - some of the more unsavoury aspects of the chocolate industry, but that's another story).

Cocoa beans grow in pods, with 20 to 60 beans per pod. The number of pods produced by each tree depends on several factors such as the variety of cocoa being grown, the skill of the grower, and the amount of chemical inputs that are used. But on average, each tree produces about 75 pods per year. Seventy-five pods will yield approximately 3kg of dried, saleable cocoa beans.

After the cocoa pods are cut from the tree, they are broken open, and the beans are scooped out. At this stage, the beans are encased in a sweet, tangy, white pulp, which tastes somewhat like mango. The beans themselves range in colour from white (as is the case with Criollo), to bright purple (as is the case with Forastero). Fresh out of the pod, the beans are extremely unpalatable: they taste bitter and astringent, have a somewhat cheesy texture, and bear no resemblance to chocolate at all.

The fresh beans must be fermented for up to a week in order to develop so-called "aroma precursors", via a series of chemical reactions. To ferment properly, the beans must be placed in a large enough pile to prevent them from drying out. Sometimes, a fermentation heap is made on the leaf-strewn floor of the plantation, while in larger plantations and co-ops it is common for special wooden fermentation boxes to be used for fermenting the cocoa.

If you'd like to know more about fermentation, please have a look at a page I put together for the Tava website called "Theobroma cacao: from Bud to Bean".

Once the beans have been adequately fermented, they must be dried in order to halt the fermentation process, and remove excess moisture. Proper drying helps prevent the beans from rotting or going mouldy.

Methods of drying cocoa beans vary substantially between countries and plantations. In some places, rainfall is low enough to allow the beans to be sun dried. Usually this means that a single layer of beans is placed on a sheet of plastic, or on a concrete slab, or even (though not desirably) on an asphalt roadway!

Cocoa pods at various stages of ripeness
Cocoa pods at various stages of ripeness

A basic structure used for force-drying cocoa in Vanuatu. Most of the building materials come from the surrounding jungle.
However, because cocoa trees thrive in the wet tropics, many cocoa growing regions are too wet to enable sun drying. In these places, the beans are force-dried. Like sun-drying, methods for force-drying vary from place to place, but the principle remains the same: the beans are placed on a platform beneath a cover (to keep rain off), and above a heat source. The heat is usually generated by a fire, which is typically fueled by wood or gas.

A basic structure used for force-drying cocoa in Vanuatu. Most of the building materials come from the surrounding jungle.
A basic structure used for force-drying cocoa in Vanuatu.
Most of the building materials come from the surrounding jungle.

There is nothing inherently wrong with force-drying cocoa beans, but unfortunately, force-drying methods are often poorly executed, leading to a number of potentially serious defects in the finished product. One of the most common - and serious - defects caused by force-drying is smoke-taint in the beans. Smoke taint occurs when the beans are exposed to smoke from the heat source, leading to an end product that smells and tastes smoky. Occasionally, smokiness in chocolate is promoted by manufacturers as a desirable characteristic, but the reality is that the "smoking" of cocoa beans is an accidental and uncontrolled process (unlike the carefully controlled smoking of products such as ham, cheese, or whisky). Smoky cocoa beans are considered to be defective and unmerchantable under the International Cocoa Standards [1].

When the beans have been fermented and dried, they are packed up in jute sacks. Typically, each sack weighs 60kg. The beans are then shipped to manufacturers, the vast majority of whom are located in Europe and the USA.

Most of the world's cocoa beans are processed into cocoa liquor, cocoa butter, and cocoa powder by a handful of huge multinational companies that sell these pre-processed ingredients to chocolate factories. Hence, you'd be correct in reaching the logical conclusion that most so-called "chocolate makers" don't actually work with raw cocoa beans at all.

But a small - and growing - group of chocolate devotees around the world do make chocolate from raw cocoa beans. As with the fermentation and drying of cocoa beans, there are many different methods of manufacturing chocolate, but the basic principles remain the same:

First, the beans must be cleaned of foreign matter such as dust, jute fibres, sticks and stones.

Unroasted cocoa beans. The beans in this image are about actual size
Unroasted cocoa beans. The beans in this image are about actual size

Next, the beans are roasted to produce the desired chocolatey flavour. Roasting times and temperatures vary depending on the variety of bean being used, and the type of chocolate that is to be made. During roasting, the beans undergo a chemical process called a Maillard reaction, which is a browning reaction. The Maillard reaction in cocoa can produce many desirable (and undesirable) flavour characteristics in chocolate, including caramel, nutty, earthy, malty, and coffee flavours and aromas (as well as sour, musty, and burnt flavours and aromas).

After roasting, the beans are cracked and winnowed. Winnowing is the process of blowing air over the cracked beans to remove the crisp, papery shells from the edible nibs.

The roasted, winnowed cocoa nibs are turned into cocoa liquor by grinding. Cocoa liquor is not alcoholic (the word "liquor" really just means "liquid").

When the desired ingredients (namely cocoa liquor, sugar, and possibly milk powder, vanilla, and an emulsifier) have been combined, the warm chocolate paste is refined in order to produce a small, consistent particle size in the product. A small particle size creates a silky mouthfeel in the finished chocolate. Traditionally, roll refiners have been used for this process (whereby the chocolate passes between closely-spaced rollers). However, many factories these days use other means of refining, such as ball mills (whereby the chocolate ingredients are placed in a vessel which is partly filled with small metal balls. The chocolate and the balls are agitated for a period of time, which causes the balls to crush and break up the chocolate particles).

To make an extra-buttery chocolate, additional cocoa butter is often added. Chocolate made without extra cocoa butter can have a dry and crumbly texture. To obtain cocoa butter, it must be separated from cocoa liquor by placing the liquor under immense pressure. The by-product of pressing cocoa butter - called presscake - is pulverised to make cocoa powder.

The refined chocolate - with cocoa butter added - is then conched. Conching is a process that was stumbled upon by Rudolph Lindt in the 1870s. Conching takes its name from the machine orginally used by Lindt, which he thought resembled a conch sea-shell. The principle of conching is that the warm chocolate is mechanically agitated or kneaded, continuously, for a period of time that can extend to several days. Conching improves the flavour of the chocolate by expelling harsh-tasting volatile acids. In a factory with modern refining machinery, conching does not further refine the particle size of the chocolate, but conching is believed to improve the texture of the chocolate by smoothing the rough edges of each particle, and by evenly coating each particle in cocoa butter.

The final process prior to moulding is tempering. Correct tempering produces a very glossy chocolate, which makes a nice sharp snap when broken. Correctly tempered chocolate will also resist problems associated with temperature fluctuations, such as fat bloom. (Fat bloom is the dull grey film which sometimes forms on chocolate, and can be mistaken for mould).

Most chocolate is about 40% fat. Tempering is the process of producing the most stable form of fat crystal in the cocoa butter. Cocoa butter can crystallize (or solidify) in several different forms, each of which has a different melting point. The most stable cocoa butter crystal is known as the beta (β) form.

During tempering, the beta form of cocoa butter is produced by precisely manipulating the temperature of the melted chocolate. First, the chocolate is heated until all of the crystals in their different forms have melted (45ºC is adequate). Then, the chocolate is cooled to a temperature at which beta crystals can form, but which is still warm enough to prevent the undesirable crystals from forming (the correct temperature is about 29ºC).

The tempered chocolate can then be poured into moulds, cooled to set ... and then enjoyed!


References:
1     The international cocoa standards are set out by the International Standards Organization, in the document ISO 2451



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Copyright © 2008 Chocolate Review
Bibliography

Madell, Samantha. "How chocolate is made." thechocolatereview.com. 8 June 2006. Web. 15 June 2017.

Published 15 June 2017 LR
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