Once cooled, the chocolate can then be heated again to just below the melting point of form V – this melts forms I-IV, which all have lower melting points, but not the form V crystals. Tempering involves allowing the melted chocolate to cool very slowly, as this increases the amount of form V that is formed in the mixture. Obviously, this isn’t ideal, as forms I-IV have less than desirable properties that impact on the quality of the chocolate. If melted cocoa butter is simply allowed to cool naturally, a mixture of forms I-V will be obtained. Unfortunately, it’s not the most stable of the six, and requires a process called ‘tempering’ in order for it to be the main structure present in manufactured chocolate. This form has a shiny appearance, produces an audible snap when broken, melts in the mouth, and has a smooth texture. The best crystal form for chocolate, in terms of it exhibiting the best appearance and taste, is form V.
![can crystal maker define specific crystalline structures can crystal maker define specific crystalline structures](https://www.researchgate.net/publication/334134606/figure/download/fig2/AS:775833941704712@1561984634954/Primary-polymorphic-crystalline-phases-of-PVDF-Reproduced-with-permission-from-50.png)
These, additionally, can affect the taste and quality of the chocolate, so it’s an important factor to consider for chocolate makers. These crystal structures differ in how the molecules are arranged, which in turn influences their properties, such as appearance, taste, and texture.
![can crystal maker define specific crystalline structures can crystal maker define specific crystalline structures](https://cen.acs.org/content/dam/cen/94/2/09402-notw1-revelatorycxd.jpg)
The more efficiently they are stacked together, the higher the density of the structure formed, and the more stable.Ĭocoa butter has at least six different structures, or ‘crystal forms’ the ability of a substance to display different structures is known as ‘polymorphism’. The molecules themselves don’t change at all in these different structures what does change is how they are arranged or stacked together.
![can crystal maker define specific crystalline structures can crystal maker define specific crystalline structures](https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41467-020-20855-0/MediaObjects/41467_2020_20855_Fig1_HTML.png)
This one examines the different structures of chocolate, why the tempering process is important to produce the highest quality chocolate – and why you shouldn’t leave your Easter chocolate lying around for months before eating it.Ĭocoa butter is the primary ingredient in chocolate it is composed primarily of fat molecules, and how these fat molecules are arranged determines the structure of chocolate. With Easter upcoming, here’s another graphic on chocolate to go with the previous food chemistry graphic which looked at some of the chemicals it contains.