How to store chocolate

A steady 15–18°C, relative humidity below about 55%, wrapped or in a sealed container, out of direct light. A cool cupboard away from the oven is usually the best available domestic option. Wine storage conditions are close to ideal if you have them.

Foil is not decorative and it is not nostalgia. It answers three of the four conditions above at once, which is why the convention survived into an era of cheaper materials.

Odour. Cocoa butter is a fat, and fat takes up volatile aromatic compounds readily. Chocolate stored unwrapped beside anything strongly scented will absorb it, and the effect is not subtle. Foil is a far better barrier to volatiles than paper or than most plastic films.

Light and oxygen. Both degrade chocolate over time — fats oxidise, and the result is a stale, faintly cardboard-like note that appears long before anything looks wrong. Foil is opaque and effectively impermeable, which no transparent film is.

Moisture. Sugar bloom happens when moisture reaches the surface, dissolves sugar and leaves it recrystallised as a grey film. A moisture barrier is a shelf-life decision rather than a presentational one.

The paper band that traditionally wraps the foil does a fourth job: it carries printing, which foil takes badly, and it adds a little physical protection. Modern metallised films do most of the same work more cheaply, which is why a wrapper that looks like foil frequently is not one.

Two reasons. Condensation forms on a cold surface when the chocolate is taken out, dissolving surface sugar and leaving sugar bloom when it dries. And a fridge is full of aromatic food — cocoa butter absorbs odours efficiently, so refrigerated chocolate frequently picks up whatever else is in there.

In a hot climate with no cool storage, refrigeration beats melting. Wrap the chocolate airtight first, and when taking it out let it come fully to room temperature before unwrapping, so any condensation forms on the wrapper rather than on the chocolate.

Chocolate stored near coffee, spices, cheese or cleaning products will take on their smell, and it is not reversible. This is why chocolate is wrapped in foil or metallised film rather than paper alone, and it applies at home as much as in a warehouse.

A ganache-filled truffle contains cream and is genuinely perishable — days to a couple of weeks refrigerated. Solid chocolate keeps for months to years. The storage advice above is for solid chocolate; anything with a fresh filling follows the filling's rules, not the chocolate's.