[jihadjihad]

This is very strange to see on HN this morning...I was bored last night while eating a piece of dark chocolate, and began wondering how exactly they make it.

I learned something fascinating: the primary thing that distinguishes "good" chocolate from "bad" chocolate, apart from taste, is the texture--more specifically, the crystal structure of tempered cocoa butter. There are in fact six different crystal forms of cocoa butter [0], each with its own unique properties. The "goal" when making good chocolate is to allow as many Type V crystals to form as possible, because they have the best properties (great texture, good snap, glossy appearance as opposed to matte, and the melting temp is higher, closer to body temp).

In order to form a majority of Type V crystals, chocolate is first melted at a high temp to wipe the slate clean, so to speak (all six crystal forms are melted). It's then cooled so that Type IV and V crystals can form, then heated again slightly to melt any remaining Type IV crystals, leaving only Type V. Wonderful stuff!

0: https://en.wikipedia.org/wiki/Chocolate#Tempering

[gonehome]

You can see them do this tempering process often when working with chocolate in The Great British Baking Show (in order to get the chocolate to be shiny).

[knuthsat]

Sounds a lot like annealing.

[riffraff]

it's called "tempering", tempering and annealing are somewhat similar processes.

[RangerScience]

Ah, but that's only the case for tempered chocolate! You can find a lot of the older style (stone ground) around, and notably, the Sicilian town of Modica has a 300+ history of it: https://en.wikipedia.org/wiki/Cioccolato_di_Modica

[Xophmeister]

You can also do it by seeding, using chocolate with the right crystalline structure. This method is usually a lot less troublesome than the thermal shocking (tempering) approach.

[wastedhours]

You can also seed with the cocoa butter you add in, seeding with pre-tempered chocolate tends to require more added as far as I remember.