Chocolate snaps and shines only when its fat crystallises in form V
Cocoa butter melts just under body temperature, which is why a bar stays solid on the shelf and dissolves on the tongue. But the fat can crystallise in six different ways, each melting at its own temperature, and only one of them gives chocolate its gloss, smooth texture and clean snap.
The fat is pressed from the cocoa bean. Beans are fermented, dried, roasted and shelled to give nibs, which are roughly 54 to 58 percent cocoa butter. Grinding the nibs yields cocoa mass, also called chocolate liquor, and pressing that separates the pale yellow fat from the dry cocoa solids. Despite the name, there is no dairy involved, so it is vegan, and it carries only traces of the caffeine and theobromine found in the solids. Chemically it is dominated by a few triglycerides built from palmitic, stearic and oleic acids.
Its crystal behaviour is the chocolatier's central problem. Six forms are recognised, labelled I to VI, melting at temperatures ranging from about 17 up to 36 degrees Celsius. Tempering aims to lock the fat into form V, the most stable one that can grow from melted cocoa butter; form VI appears only after long storage or from solvents. A bar that melts in a warm room and resets without tempering forms unstable crystals and develops the whitish film known as fat bloom. Origin matters too: Malaysian and Indonesian butter sets faster and harder than Brazilian, with West African in between.
Early producers simply boiled cocoa mass in water and skimmed off the fat. Hydraulic presses arrived in the 18th century and the more efficient Van Houten press in the later 19th. For a long time the butter was a chocolate-factory by-product sold mainly to cosmetics makers and pharmacists, and only with the rise of confectionery did it become a standard chocolate ingredient. It still suits medicine well: solid at room temperature, harmless, and melting in the body, it makes an ideal base for suppositories, and its natural antioxidants give it a shelf life of two to five years.
Because it is expensive, manufacturers look for stand-ins such as shea butter, palm fractions and mango kernel fat, and adulterated batches can be spotted by their paler colour and weaker glow under ultraviolet light. The rules differ: in the United States chocolate must use cocoa butter as its only fat, while the EU allows other fats up to 5 percent. A recent review notes that climate pressure on cocoa supply is spurring work on engineered yeasts and crops, though matching the butter's exact structure remains hard.
Source: Cocoa butter
