Tempering chocolate

Cocoa butter can set several ways

Cocoa butter is a fat that can crystallise into several different structures. Most of them are soft, dull, unstable and melt too easily. One of them is hard, glossy, stable and melts just below body temperature.

When chocolate is simply melted and left to set, it forms a mixture dominated by the unstable forms. The result is dull, soft, streaky, prone to white bloom, and it melts on the fingers.

Tempering is a sequence of temperature changes that encourages only the good crystal form to seed and grow. Everything about the method — melt fully, cool, warm slightly — exists to select for that one form.

The seeding method, which is the easiest reliable one

It uses already-tempered chocolate to supply the right crystals rather than creating them from scratch.

1. Chop the chocolate finely and set aside about a third of it.
2. Melt the other two thirds gently over barely simmering water, or in short bursts in a microwave, stirring between each.
3. Melt it completely — every crystal must go, or the wrong ones survive and seed the batch.
4. Take it off the heat and add the reserved chopped chocolate, stirring continuously.
5. The unmelted chocolate cools the melted chocolate and supplies stable crystals to seed it. Keep stirring until it has all melted and the mixture has cooled and thickened slightly.
6. Test it: spread a little on a knife or a piece of parchment. Tempered chocolate sets within a few minutes at room temperature, glossy and firm.
7. If it stays soft or dull, it is not tempered. Rewarm slightly and add more seed chocolate.

What goes wrong

Overheated

Chocolate scorches easily and seizes. Gentle heat and short bursts, always.

A drop of water

Seizes chocolate instantly into a stiff grainy mass. Everything must be bone dry.

Not fully melted first

Surviving unstable crystals seed the whole batch wrong.

Too warm when set

Stays soft and dull. It needs to cool while working.

Set in the fridge

Cools too fast and gives the wrong crystals and often a dull surface.

Bloom

The white or grey film on old chocolate. Fat bloom is cocoa butter that has migrated and recrystallised; sugar bloom is moisture. Neither is harmful and both are cosmetic.

Cheap chocolate

Compound chocolate uses vegetable fat rather than cocoa butter and does not need tempering at all.

When you need it and when you do not

• Needed: anything set as chocolate and eaten as chocolate — bars, moulded shapes, coated truffles, dipped fruit, decorations.
• Not needed: chocolate melted into a batter, a ganache, a mousse, a sauce or a cake. Other ingredients change everything.
• Not needed: compound or cake covering, which uses vegetable fat and sets hard regardless.
• Ganache does not temper, and it does not need to — the cream changes the fat structure entirely.
• Seized chocolate can be rescued into a ganache or a sauce by adding more liquid deliberately, though it will never temper.
• A microwave works for tempering if used in short bursts with stirring, and many professionals prefer it.

Common questions