Story of the blues: Most of us buy Stilton only at Christmas but it's a versatile year-round treat

Claire McDonald finds out what makes the festive favourite so delicious

Huge truckles of stilton balance on market stalls along the cobbled high street of Melton Mowbray. Wedges of the blue cheese, festooned with holly, fill the glass cabinets of Dickensian-looking pie shops. People bustle from shop to shop, laden with bags, as the Christmas lights above them twinkle. It would be difficult to imagine a more festive scene.

Stilton, the "king of English cheeses", is synonymous with Christmas. It is as festive as oranges studded with cloves, cranberry sauce and large tins of Quality Street. So much so that Marks & Spencer makes 70 per cent of all its stilton sales in December.

The reason for this seasonal link is not altogether clear. Stilton production has evolved over so many centuries it is difficult to trace why it is seen as a Christmas luxury. One theory is that for many years cheese was made between April and June, with the first flush of milk. After a harsh winter spring would bring a swell of milk to feed the new calves and the excess was turned into cheese. As stilton took between six and eight months to mature, it was ready in time for Christmas and became a seasonal treat.

"Stilton is perfect at the end of a festive meal, with a glass of Port, to help digestion," says Patricia Michelson, proprietor of famous London cheese shop La Fromagerie. "Port and stilton are a match made in heaven." But she believes stilton shouldn't just be a Christmas luxury and that it should be eaten throughout the year. "I love it in the summer. It goes so well with crisp salad leaves and nuts. With shorter maturing times, these days it is summer stilton which is made with the first of the spring milk, so it has a lovely fresh flavour, different to winter Stilton, which is sweeter."

Apart from shorter maturing times, making stilton hasn't much changed since the factories began producing it in the mid-1700s, although that's not how it feels as I am led through the doors of Tuxford and Tebbutt, in Melton Mowbray, Leicestershire, one of only six stilton producers in the world. There is a strong smell of chlorine and it feels more like the entrance to a swimming pool than a traditional creamery. However, rather than don a swimming costume, I am asked to put on a fetching red hairnet, blue plastic shoe protectors, a white coat and large amounts of antibacterial soap.

Sanitised, I am allowed into an area where vast metal baths are each filled with 10,000 litres of warm milk every day. It sits in creamy swirls and I have to fight an urge to dive in, Cleopatra-style. Well, Cleopatra in a hairnet. Once the bath is full, a cup of culture is poured in, which allows the signature blue veins to grow. This is a fairly modern development. When stilton was first made by farmers' wives hundreds of years ago, the blue veins were invoked by more haphazard methods. The original stilton cheeses were air dried for several months in barns or lofts, alongside saddles and horses' harnesses, which were also stored there. Damp leather often harbours "penicillium roqueforti" (blue mould spores) and sometimes these would get into the cheese and cause it to go blue, allowing the cheese maker to charge a premium for the prized blue veins.

Next, a setting agent is added to the milk and in the olden days they would have shaken a calf's stomach over the milk to get the naturally occurring rennet from it. As I had asked to be involved in the cheese-making process I was pleased to discover that this is no longer the case. Instead a cup of liquid vegetarian rennet is added to the milk, and then it is left for 40 or so minutes before the "cutting" takes place. "This is what tells you if someone is a good cheese maker," says Alan Whiston, factory manager and a blue cheese man, through and through. He's been in the business for 25 or so years and started at the bottom. "You need to be able to know exactly when the moment is right. Too soon and perhaps you should go and put a brew on," he says.

The cutting involves pulling a grid of wires first vertically and then horizontally through the setting cheese. It forms Oxo-sized cubes of curdled milk, which lets in air to start the moulding and allows the liquid whey to run off.

Ninety per cent of the milk is lost in whey during the stilton-making process and it explains why Melton Mowbray is also famous for pork pies. Pigs love whey and in an admirable example of waste not, want not, the cheese makers invited pie makers and their pigs to the area to eat the excess whey. And lo! The Melton Mowbray pork pie was born.

Once cut, the cheese is left in a hot and humid room, where the bacteria are allowed to develop overnight, turning the vat into a huge petri dish. Cheese makers then manually scoop 12kg of the crumbled curd into a tall cylindrical plastic "hoop" and place it on a shelf. The whole process is remarkably unautomated, with very few machines other than a conveyor belt. The men – and it is mainly men in the factory as the work is physically demanding – turn the hoops once each day for six days to prevent the cheese losing its shape.

The hoop is then removed, the cheese keeps its shape and is sealed by hand with a mix of curd and water. This looked like fun, a bit like throwing a pot on a pottery wheel. However, it is trickier than it looks. As I bent to pick up the enormous cylinder of stilton, the cheesemaker told me it was the weight of a baby. I felt confident. I've been picking up a lot of babies recently. What he failed to mention was that this cheese was the weight of a 10kg baby – more a toddler, really. After some comedy staggering, I managed to get the cheese onto the prongs where it rotated, and I scooped up handfuls of glorious gloopy curd and smothered the cheese with it – a strangely soothing process.

During 10 weeks in a cool storeroom, the cheese is frequently graded for smell, taste and appearance, as well as being pricked to allow air in, which lets the mould mature. Finally it is ready.

With modern packaging it is possible to buy small portions of the cheese, but this wasn't always the case. It used to be that stilton was only sold whole and Christmas was when you worked your way through the entire 7.5kg truckle. Now you can even buy mini-truckles, but some cheese experts advise against it. "Smaller truckles mean you get a higher rind to cheese ratio, which means the cheese is slightly dryer," says Huw Mainwaring, food product developer with Marks & Spencer. This is why M&S don't indulge; instead they sell Half Moons, which is 1kg of a large truckle, so the rind/cheese ratio is correct. It also means that this Christmas you can be a "big cheese" – and who can resist that? Buying a large cheese used to be a sign of wealth and status, and this is where the term comes from.

Cheese etiquette

Avoid the wrath of fellow cheese lovers and learn how to slice nicely on the cheeseboard.

Don't cut off the cheese's "nose". Always cut from the centre point, where the flavour is most concentrated, to the rind. This means each slice will have the full range of flavours, starting with the sweetness of the nose progressing to a dryer taste towards the rind.

Cut flat soft cheeses such as brie like a pizza. Cut cylindrical cheeses such as stilton into a wedge, place it on its side and then cut in slices from the thin end up towards the rind.

Warm Stilton, caramelised pear, hazelnut and bacon salad

Serves 2 people as a starter

4 rashers of bacon
2 pears
150g Stilton
1.5tbsp caster sugar
120-160g salad leaves
splash of balsamic vinegar

Cut the bacon into small pieces and fry them in olive oil. While they are frying slice the pears into quarters, remove the core and then dice into 1cm cubes. Once the bacon is crispy, remove from the pan and put the pears in with the bacon fat. Fry for a minute or so. Add caster sugar and toss in the pan using a wooden spoon. Cook for about 5 minutes, until they are caramelised, but take care as this is very hot. Put bacon back in the pan and heat a little. Empty the salad leaves into a large bowl. Add crumbled stilton, nuts, pears and bacon. Toss thoroughly and add a splash of balsamic vinegar.