Chocolate in savoury cooking

Sweetened chocolate is the recent form. The Mesoamerican preparations that cacao was used in for the great majority of its history were seasoned rather than sweetened — chilli, achiote, vanilla, flowers and aromatic seeds appear throughout the record, and sugar arrived with Europeans.

So a savoury use of cacao is not a modern novelty or a chef's provocation. It is closer to the older practice, and the surprise people feel at it is a fact about the last few centuries rather than about the ingredient.

The living demonstration is mole, which is a family of Mexican sauces of which some contain cacao, none is sweet, and the cacao is there for bitterness, colour and depth.

Three things, and none of them is chocolate flavour in the dessert sense.

BITTERNESS. Cocoa's polyphenols, theobromine and caffeine give a long bitter backbone. In a rich, fatty, spiced dish that bitterness does what tannin does in wine: it gives everything else something to push against and stops the whole thing being flat.

COLOUR AND BODY. Cocoa solids darken a sauce substantially, and the small amount of fat contributes to its texture. A tablespoon of cocoa in a chilli or a stew is doing visible work.

SHARED ROAST AROMA. Cacao, chillies, spices, nuts, onions and browned meat have all been through Maillard reactions, and all of them carry pyrazines. Cocoa therefore does not sit apart from the other ingredients — it shares aroma with them, which is why a well-judged savoury cocoa reads as depth rather than as chocolate.

That last point is the whole technique. When it works, nobody says "I can taste chocolate"; they say the sauce tastes deeper than they expected.

USE UNSWEETENED COCOA, CACAO NIBS OR 100% MASS. This is the rule that matters. Sugar in a savoury sauce reads as a mistake, and a 70% bar is still roughly a third sugar. Almost every failed savoury chocolate dish is a sweetened chocolate in a dish that had no use for sugar.

USE VERY LITTLE. A tablespoon of cocoa in a large pot of chilli is a normal quantity. The dish should not taste of chocolate.

ADD IT EARLY AND COOK IT. Cocoa needs time and liquid to disperse and to lose its raw dustiness, and a long simmer integrates it. Stirred in at the end it tastes of powder.

PAIR IT WITH FAT AND ACID. Cocoa's bitterness needs both. A dish with fat but no acid becomes heavy; a tomato, a splash of vinegar or a squeeze of citrus fixes it.

AND SALT PROPERLY. Salt suppresses bitterness perception, so an under-salted dish with cocoa in it will taste harsh in a way that is easily mistaken for too much cocoa.

CHILLI AND BEAN STEWS. The most reliable savoury use in an ordinary kitchen, and the one closest to mole's logic — chilli, cumin, tomato and cocoa share roast aromatics.

RICH MEAT AND GAME SAUCES. Venison, hare, oxtail and beef braises all carry enough fat and enough browned character to take cocoa. It appears in several European regional preparations, and Italian dolceforte sauces are a documented precedent.

DRY RUBS. Cocoa in a barbecue rub is now common, and it works: it browns, it contributes bitterness against the rub's sugar, and it darkens the crust.

CACAO NIB CRUSTS AND GARNISHES. Nibs are unsweetened, crunchy and intensely cocoa, and they work scattered over roasted vegetables, on a cheese, or crushed into a crust for a fatty fish or a piece of meat.

WITH ROASTED VEGETABLES, particularly the sweet earthy ones — beetroot, squash, sweet potato, cauliflower — where a little cocoa in the roasting spice mixture adds depth.

AND WHERE IT DOES NOT BELONG: anything delicate. Cocoa is loud, dark and bitter, and a white fish, a light broth or a spring vegetable dish has nothing for it to do.