The cheese that rots from inside

Two French cheeses, two directions. A Camembert ripens from the rind inward: the white mould on the surface changes the chemistry of the paste just beneath it, and the softening eats its way toward the centre. A Roquefort ripens from the inside out, because its mould cannot grow without air, and the air has to be let in through holes.

That single constraint — where the oxygen is — explains the shape of both cheeses, the tools used to make them, and in Roquefort's case, why an entire mountain had to be written into the law.

Camembert: the rind is a machine that moves inward

A Camembert begins as a curd that has been ladled into moulds and turned out wet. It is salted, sprayed with Penicillium camemberti, and put somewhere cool and humid. The mould grows as a felt on the outside. What it does there is chemical, and the chemistry is the whole story: the mould consumes lactic acid at the surface, the surface pH rises, and a rise in pH makes the casein proteins loosen their grip on each other.

Loosened protein is soft protein. So a band of soft, pale paste forms directly under the rind — the creamline — and thickens as the weeks pass, moving inward at a fairly predictable rate. A cheese eaten young has a thin creamline and a core that squeaks against the tooth; the French word for that core is crayeux, chalky, and it is a defect in a Camembert de Normandie and a selling point in nothing at all.

This is why "ripe" is a position on a clock, not a property. The same cheese at twenty days and at fifty days is two different foods, and neither is wrong. A Camembert that has gone fully liquid has run past the point most Normans would choose; a Camembert that is uniform and chalky never started.

Roquefort: the mould cannot swim

Penicillium roqueforti has a requirement the white moulds do not: it needs oxygen. A solid block of cheese has none in its interior, so a blue cheese is built to have holes. The curd is cut coarse, drained without pressing, and left with irregular openings between the grains. Then the wheels are pierced with needles — dozens of holes through the flat faces — and the air that enters those holes is what lets the mould vein the paste.

The blue-green colour is a pigment the mould makes only where it is growing in air. This is the detail that makes the two cheeses mirror images: in a Camembert the mould works in the place with the most oxygen (the surface) and the change moves inward; in a Roquefort the surface is the one place the mould is not wanted, so the air is delivered to the interior through a manufactured pore system, and the change moves outward from each needle track.

Why a court had to rule on a cave

Roquefort-sur-Soulzon sits under a cliff of the Combalou, and the rock below the village is not solid. It is a pile of collapsed limestone — scree, in blocks — and through that pile run cracks called fleurines. They behave like chimneys. Air is cooled by the rock walls, sinks through the fissures, and picks up moisture from the groundwater on the way down. The cellars cut into that rubble therefore sit in a moving draught at roughly 10 °C and above 80 per cent humidity, all year, without a compressor.

That draught does two things at once. It keeps the temperature steady, and it keeps the air moving, which is what the mould needs and what a sealed room cannot give. The cellars are stacked — the producers count up to eleven levels underground — and the cheeses stand on edge on oak slats so the air passes over both faces.

In 1961 the tribunal at Millau decided something unusual: the method for making Roquefort could be followed anywhere in the south of France, but only cheese ripened in the caves of the Combalou could carry the name. Not the recipe, not the breed, not the valley — the air. It is the clearest case in French food law where a natural ventilation system is the protected asset.

The herd is in the specification too

The rules reach back past the cave to the field. Roquefort is made from raw whole milk of the Lacaune breed, and the ewes must be kept in the defined area, with at least three quarters of their annual feed coming from it. Grazing is compulsory on every day the weather and grass allow, and permanent indoor housing is banned.

That last clause is the interesting one, because it is a flavour rule disguised as an animal-welfare rule. A ewe on pasture eats a shifting mix of grasses and herbs through the season, and that mix reaches the milk. Confine the flock and the milk gets more uniform, which is good for consistency and bad for the thing the appellation is trying to protect. The law is choosing variability on purpose.

How to taste the direction

Cut a Camembert through the middle and look at the edge of the cut. You should see three zones: rind, a pale runny band, and a firmer centre. The thickness of that middle band tells you how far the ripening has travelled. If there is no band, the cheese is young; if there is no centre, it has finished and is on its way to ammonia.

For a Roquefort, break rather than cut — the paste is crumbly by design, and a knife compresses the veins. Look at where the blue sits: it should follow lines, not be scattered evenly like dye. Lines mean the mould grew along the needle tracks, which means the cheese was made the way the appellation describes. Even dispersion means the mould was mixed into the curd and had nowhere in particular to go.

This is entry 03 of Food in About France. The pillar's argument — a dish is a region, a rule and a technique at once — is set out on the pillar page.