How to Make a Chocolate Drip Cake

The drip ratio sits between a thin, pourable glaze and a firmer soft filling, thick enough to hold its shape partway down the cake rather than pooling at the base. Figures below are for 200 g of chocolate as a working batch size; scale both numbers together for a larger or smaller batch.

1. Chill the cake fully before doing anything else. The cake should be crumb coated, then genuinely cold, either refrigerated for 30 to 60 minutes or chilled in the freezer for 15 to 20 minutes; a trade convention starting point rather than a fixed rule, since a home freezer and refrigerator both vary in how cold they actually run.
2. Weigh the chocolate and cream on a kitchen scale at the ratio for your chocolate type from the table above.
3. Heat the cream until just simmering, then pour it over the chopped chocolate in a heatproof bowl, or melt both together gently over a bain-marie. Let it sit for a minute before stirring, then stir with a heat resistant spatula until fully smooth.
4. Let the ganache cool until it thickens slightly and coats the back of a spoon, still fluid but no longer hot to the touch. Pouring it too hot is the single most common reason a drip runs too far.
5. Test one drip on the back of the cake, or on a chilled test board, before committing to the front. If it runs too far, let the ganache cool a few minutes longer or add a small amount more chocolate. If it barely moves, warm it slightly or add a touch more cream.
6. Transfer the ganache to a piping bag such as an reusable piping bag with the tip snipped small, or a squeeze bottle.
7. Working around a cake turntable, apply drips just over the top edge at varying points around the circumference, letting gravity pull each one down the side to a different length for a natural look, rather than aiming for identical drips.
8. Once the drips have set, fill in the top of the cake with the remaining ganache and add any toppers or decoration.
9. Return the finished cake to the refrigerator to fully set before it travels or is moved, since a drip that has only partially set can smear or slide during transport.

This is almost always one of two causes, and usually both together: the cake was not cold enough when the ganache went on, or the ganache itself was poured too hot and too thin. A cold cake surface causes the ganache to firm up quickly on contact, which is what stops a drip partway down; a cake at room temperature gives the ganache nothing to set against, so it simply keeps flowing under gravity until it runs out of cake or reaches the board. Chilling the cake properly, not just for a few minutes but the full 30 to 60 minutes a crumb-coated cake needs in a refrigerator, along with letting the ganache cool to a coats-the-spoon consistency before pouring, resolves the great majority of runaway drips.

Yes, and it is a simpler process for anyone who does not want to work with cream at all: melted candy melts thinned slightly with a neutral oil behave similarly to ganache for drip purposes, running down a cold cake and setting as they cool, without needing tempering or a chocolate-to-cream ratio at all, since they contain no cocoa butter to manage. The tradeoff is flavor and mouthfeel, since candy melts taste noticeably less like real chocolate than a ganache drip made from couverture, and the color range on candy melts, while wide, is a different product from real white or milk chocolate for anyone trying to match a specific finish.