The cacao tree and its fruit
The history of chocolate
How is chocolate made?
Random facts about chocolate
(courtesy of ChocoMuseo)
Ideally, this process must be started within 4 to 6 hours (or at most within 2 days) of harvest. It should last for 3 to 9 days, depending on variety and climate.
The seeds, along with the mucilage, are scooped into boxes and covered with banana leaves. The fermentation starts with an anaerobic phase (yeasts split sugar into alcohol and C02). The next phase is aerobic (alcohol is converted into acetic acid). There, temperature raises up to 50°C (122°F) and kills the germ. Finally, flavour precursors, that will give cacao its chocolate flavour during the roasting, are created. In order to guarantee a homogeneous fermentation, the cacao should be mixed every other day. Fermentation is complete when the seeds turn a deep brown.
The roasting process enables to:
- fully release the rich aromas in the beans
- reduce the remaining moisture to 1.5 to 2%
- remove acids and bitter substances
- eliminate enzymes that cause degradation
- make it easier to remove the shells of the seeds.
Large rotating ovens roast the seeds at temperatures between 100 and 140°C (210-280°F) - which is a lot milder than for coffee - and should follow a precise curve. If the temperature goes too high, starch caramelizes and the beans loose fat content, resulting in a degradation of taste.
Roasting can last anywhere from 20 minutes to 2 hours, depending upon the unique characteristics of the cacao (variety, bean size, moisture, plumpness...).
Winnowing is the process of separating the shells from the bean.
Once the bean has been roasted, the outer shell is loosened and one is able to easily remove it.
Inside a typical winnowing machine, cones (which are serrated like the edges of a knife) crack open (rather than crush) the thin shells to get at the seeds. Fans then blow away these empty husks. Finally, the remaining broken seed bits, called "nibs", pass through a series of sieves, which strain and sort the nibs according to size.
The nibs themselves comprise 50% to 55% of cacao butter and 45% to 50% of pure cacao solids.
In the grinding step, the nibs are milled: crushed by heavy steel or stone discs. This process generates enough friction and heat to liquefy the nibs into a thick paste, called cacao liquor.
Some of the chocolate liquor is placed in a hydraulic press, which squeezes out the cacao butter. This fatty, yellow substance drains away through metallic screens.
Then, it can be added to dark or milk chocolates, used as the basis for white chocolate, or used in cosmetics and medicine.
Once cacao butter is extracted, the remaining solid cacao is pulverized into cacao powder. This very product is used in beverages, cooking and baking.
Refining & conching
After cacao liquor has been mixed with other ingredients (cacao butter, sugar, powder milk, vanilla...), the refining process starts. The mix goes through a series of steel rollers that reduce the particle size down to 20 or 30 microns. A chocolate that is not refined enough (above 50 microns) is coarse and grainy; on the contrary, too much refining (below 15 microns) turns chocolate pasty and gummy.
During the following process, called conching, the chocolate is mixed for several hours or even days (which results in heating as well). At this stage, remaining acidity, bitterness and moisture disappear and little particules get covered with cocoa butter, which gives chocolate a silky texture.
Tempering gives chocolate its glossy sheen and is the reason behind the snapping sound that can be heard while breaking a piece of chocolate. The process also prevents a phenomenon known as 'fat bloom' (when white spots and changes in texture appear).
This process consists in changing the molecular structure of the cacao butter, through temperature variations (cf. diagram).
The first increase in temperature melts all crystals in the chocolate structure. As the temperature decreases, 5 types of crystals are generated, the type V (or 'beta', the target type) being the most abundant if the cooling is slow enough. During the next step, the temperature is raised again and kept at a level that melts all but beta crystals. On the final cooling down, almost only beta crystals are generated around the existing ones.
Finally, in a modern chocolate factory, machines squirt tempered chocolate into several hundred molds per minute. Some devices pour chocolate over flavoured centres (a process called "enrobing"). Others create chocolate shapes that will be filled with liquid before their bottoms are sealed.
Eventually, wrapping and packaging machines box the chocolates at speeds unmatched by human hands.