Blue

Every other cheese in this section is trying to knit the curd into a closed body with no air in it, because air is where things you didn’t invite grow.

Blue does the opposite on purpose, and that inversion is the whole family.

The mould needs to breathe

Penicillium roqueforti is added to the milk or the curd, and then it sits there doing nothing — because it needs oxygen, and a well-made cheese hasn’t got any.

So a blue is built to give it some:

The curd is left open. Handled gently, not pressed hard, often stacked rather than compressed, so the finished wheel has a loose, granular, imperfectly-knit structure full of tiny voids. In any other cheese that’s a defect with a name. Here it’s the specification.

And then the wheel is needled. Some weeks in, it’s pierced with long needles — dozens of channels driven through the body. Air reaches the interior, the dormant mould wakes up, and it grows along those channels.

Which is why the veining follows lines rather than being random. Those blue-green streaks are a map of where the needles went.

I find this the most satisfying piece of design in the whole craft. The entire structure of the cheese — the thing that would be a fault anywhere else — exists to deliver oxygen to a fungus.

What the mould does

P. roqueforti is a vigorous proteolytic and lipolytic organism, which is to say it takes apart both protein and fat much faster than ordinary ripening would.

That accounts for the family’s character:

• The texture goes soft and creamy near the veins, because the protein network there is being dismantled.
• The flavour is sharp and peppery, from aggressive lipolysis producing free fatty acids — the same mechanism as provolone’s bite, but further along.
• And the smell is strong, because you have a lot of small volatile compounds being produced fast.

The pairing with something sweet — port, sauternes, honey, pear — isn’t arbitrary. Sweetness balances the salt and the sharp fatty-acid notes, and blues are generally salted heavily, partly to control the mould’s enthusiasm.

The members

Roquefort. Sheep’s milk, the Combalou caves at Roquefort-sur-Soulzon, and the oldest protected name in the story — the 1411 charter protected the right to ripen there, and the modern PDO still says the milk may come from a wide area but the cheese may only be aged in the village. It is also defined as raw milk: pasteurise it and it isn’t Roquefort.

Stilton. Cow’s milk, English, and — as covered — legally impossible to make in the village of Stilton, because the PDO covers Derbyshire, Nottinghamshire and Leicestershire and the village is in Cambridgeshire.

Gorgonzola. Cow’s milk, Italian, and it comes in two quite different forms: dolce, young, soft, sweet and barely blue; and piccante, aged longer, firmer, far more assertive. Ordering “gorgonzola” without specifying gets you whichever the shop stocks, and they are not interchangeable in cooking.

Cabrales. Spanish, from Asturias, traditionally a blend of cow, goat and sheep milk, aged in natural mountain caves. One of the most aggressive cheeses in general circulation.

Bleu d’Auvergne, Fourme d’Ambert, Bleu de Gex. The French cow’s-milk blues — generally rounder and less saline than Roquefort.

Maytag Blue. American, made in Iowa since the 1940s, and a genuine part of the story of US artisan cheese predating the 1980s revival.

Cashel Blue, Lanark Blue, Stichelton. Irish, Scottish and English respectively — the last of these made to the Stilton method with raw milk, which is precisely why it cannot be called Stilton.

Cambozola. A deliberate hybrid: a bloomy rind plus blue veining plus added cream. Not traditional, frequently sneered at, and genuinely good at what it’s for.

Making one at home

I’ve dabbled in blue, and in a couple of other mould-ripened cheeses, and dabbled is the honest word — of all the families on this site it’s the one I’ve explored least. So take what follows as informed rather than authoritative.

Blue is unusual in being technically approachable and logistically annoying.

The make is not difficult — arguably easier than a bloomy rind, because you’re not managing a delicate surface. Gentle curd handling, minimal pressing, generous salting, and then needling at the right time.

The problem is that you have introduced a vigorous mould into your cave.

P. roqueforti produces enormous numbers of spores and they travel. Once blue is aging in a small shared space, expect to find it colonising the rinds of things that were not meant to be blue. The serious answer is a separate space; the practical home answer is to accept it, or to run blue in batches and clean thoroughly afterwards, or to keep blues in their own sealed container within the cave.

It’s worth knowing before you start rather than after, particularly if — like me — you have one cave and a fridge and everything shares.

The thing people get wrong

Blue veins are not “mould on cheese” in the sense that a spoiled cheese has mould on it. They are the cheese working as designed, from an organism deliberately introduced, growing in channels deliberately made for it.

What would worry me in a blue: black mould, pink or orange slime, an ammonia smell, or fuzzy growth on the outside that isn’t the expected rind. The discard rules apply to blues as much as anything — and because blues are relatively high-moisture, they get less benefit of the doubt than a hard wheel.

How to make one: Making blue cheese — the needling, and why blues are dry-salted rather than brined.

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Next: washed rinds — the orange, sticky, magnificently smelly ones.