I don’t know whether it is sad or ironic that today I watched “The Great British Menu” while eating a pizza. But anyway one of the chefs was doing “chocolate tempering”, for his dessert. It looked great, the chocolate had a beautiful sheen and he got the highest marks. I want one.

This intrigued me, so I looked up “chocolate tempering” on good old Wikipedia. Interesting science, and apparently vital to making good chocolate. I have blogged on this before.  Chocolate (or perhaps more accurately a large component of it) is crystalline and has 6 different crystal forms, of which V is the good tasting one.

This leaves chocolatiers with a problem. How to get chocolate to crystallise into the good tasting V form not the less tasty I-IV and VI forms? A partial answer is to note that apparently form VI is hard to form and forms I to IV all melt at lower temperatures than the desired form V.

So, you heat up chocolate to a quite high temperature, say 40 C or more to melt all the chocolate and then drop it into the 20s to get crystallisation started before holding it at around 30 C. 30 C is the magic temperature as the undesired crystal forms all melt at 28 C or lower, whereas the tasty form V only melts at 34 C (slightly below body temperature so don’t hold chocolate in your hand). This is tempering.

It relies on understanding how complex chocolate is, and how complex crystallisation can be. Maybe, like me you associate tempering with steel, swords, etc, the tempering of chocolate is similar. Chocolate and steel tempering are related. In both cases the object is to vary temperature to push the chocolate/steel into the crystals of the right type, and the desired size. In chocolate and steel you don’t want them to be too soft, although of course chocolate is a lot softer than steel.

So, although sadly I don’t think I will ever get to taste the dessert, at least I know a little more about chocolate. This is an official University of Surrey blog so I don’t think I can endorse any chocolate, but I think Hotel Chocolate’s chocolate must be the good form V stuff. It is sweet like chocolate.