Choosing chocolate for sauces

Pour at serving temperature, coat what it is poured over, and — for most uses — remain pourable or at least soft when it cools. Cocoa butter works against all three, because it sets firm.

So the useful move is to supply chocolate flavour with less chocolate fat. Cocoa powder plus sugar and liquid gives a sauce that stays fluid; melted chocolate plus cream gives a richer sauce that firms up considerably as it cools.

A cocoa-based sauce — cocoa powder, sugar, water or milk, simmered — is the thinnest, the most stable, and the one that keeps in a fridge and reheats. It is what most commercial pouring sauces are.

A ganache-based sauce — chocolate and cream, thinned further than a coating ganache — is richer and rounder, and it will thicken to a spreadable consistency cold. A dark chocolate around 55 to 70 per cent works; above that you need noticeably more cream.

A hot fudge sauce carries butter and sugar as well and is deliberately thick, setting chewy on cold ice cream. That set is the point of it.

Do not add water directly to melted chocolate — it seizes. If a sauce needs to be thinned, thin it with more of whatever liquid is already emulsified into it, warmed.

A sauce that has split can usually be brought back by warming gently and whisking in a small amount of hot liquid, which re-establishes the emulsion.

And for a sauce that will be poured over something frozen, err thinner than seems right. It thickens sharply on contact with ice cream, and a sauce that was correct in the pan can be unpourable on the plate.