Cookware

Double Boiler

Gentle indirect heat for melting chocolate and delicate custards

A bowl set over simmering water so the steam — not direct flame — provides gentle, controllable heat. Perfect for melting chocolate, whisking egg-based sauces, and anything prone to scorching or curdling. Keep the bowl from touching the water.

A double boiler is a simple, clever solution to a fragile problem: how to apply heat gently enough that it won't scorch or curdle. A bowl or upper pan sits over (not in) a pot of simmering water, so the food is warmed by steam at a capped temperature rather than by a hot metal surface over a flame. That indirect, controllable heat is exactly what chocolate, egg-based sauces like hollandaise and sabayon, lemon curd, and delicate ganaches need. You can buy a dedicated nesting set, but most cooks improvise one with a heatproof bowl resting on a saucepan — the principle is identical.

Types & varieties

Dedicated nesting set

Matched pot and insert that lock together; tidy but a single-use storage item.

Improvised (bowl over saucepan)

A heatproof bowl on a snug saucepan — what most cooks actually use.

Bain-marie (water bath)

The same gentle-heat idea applied in the oven, with dishes set in a pan of water.

How to set it up

Pour an inch or two of water into the lower pot and bring it to a bare simmer — not a rolling boil. Choose a bowl that fits the pot's rim snugly but not airtight, so excess steam can escape rather than building up and dripping condensation into the bowl, and make sure its bottom sits well above the water. The whole point is that steam, not direct contact, heats the bowl; if the bowl touches the water it overheats and you lose the gentle control.

An inch or two of water at a gentle simmer is plenty
The bowl should fit snugly but not airtight, so excess steam escapes instead of pooling and dripping into the food
Keep the heat low — vigorous steam can splash water into the food

Melting chocolate cleanly

Chop chocolate evenly so it melts at the same rate, set it over the gentle steam, and stir until just melted, then pull it off the heat — chocolate scorches and seizes easily. Crucially, keep all water away from the chocolate: even a drop of steam or splash will make it seize into a grainy clump. For egg sauces, whisk constantly so the eggs thicken into a smooth emulsion instead of scrambling.

Common uses

Melting chocolate for ganache, dipping, and coatingHollandaise, béarnaise, and sabayonLemon curd and other fruit curdsTempering eggs into custards gentlyKeeping sauces warm without breakingSoftening butter and caramel smoothly