(GUARDIAN) - For a small nation, the Swiss have made some pretty big contributions to world culture: muesli, Velcro, the Red Cross … and, perhaps the crowning achievement of this ancient federal republic, the fondue.

Originally conceived as a cunning way to turn old ends of cheese and stale bread into a meal (you don't get that rich by accident), it went global in the 1960s, in part, according to author David Sax , "because of the advent of the pill and swinging. Fondue cannot be enjoyed solo."

Worries about cholesterol saw beloved burner sets stashed in the attic, but you can still melt a few hearts with a bit of stringy cheese. And for those without £42 (S$74.43) to spend on a pot at one of Roger Moore's favourite Alpine restaurants this Valentine's Day, it's easy to recreate the magic at home - because nothing says romance like waking up in the middle of the night with heartburn, right?

The Swiss are an eminently sensible people. They do not hold with dunking marshmallows in bowls of liquid chocolate, and neither do I. Call it PTSD after one too many bad hen dos if you will, but the idea repulses me. This article will thus be concerned entirely with the original, and only true fondue: the cheese variety.

Which cheese, however, is contentious. As the culinary chemist Herve This explains: "Connoisseurs of fondue know that the success of the dish has to do particularly with proper cheese selection."

Flavour is important, of course, but the age of the cheese will affect how readily it melts. "Well-ripened cheese are best suited to the preparation of fondues because, in the course of ageing, enzymes called peptidases have broken up the casein and the other proteins into small fragments that are more readily dispersed in the water solution."

The most common version, which originates in the cantons of Vaud and Fribourg -although it's now found throughout Switzerland - is known as a moitié-moitié, or half and half. It's made up of almost equal parts gruyère and a local creamy cheese by the name of freiburger vacherin , which according to Swiss resident Makiko Itoh, of the blog Just Hungry , "has a full, distinctive flavour and does not make the sauce stringy".

Indeed, combination-cheese fondues are more common than single-variety: the Valaisan fondue, on the extremely comprehensive Cheeses From Switzerland site calls for raclette and emmental; both cheeses melt extremely well, but lack the savoury, umami notes of gruyère, which is the mainstay of other recipes.

The master cheesemonger Pierre Gay calls for a veritable Alpine cheeseboard for his recipe: "Comte as a base, l'etivaz for horse power, beaufort to bind and add richness, and abondance for its characteristic gentian flavour," while Patricia Michelson of London's La Fromagerie recommends emmental for its "lovely nutty flavour", beaufort alpage for its "floral richness" and a well-aged rich, caramel-sweet comte d'estive .

Gay's fondue, which lacks a more supple cheese of the emmental variety, is intensely flavoured, but easily split by the novice fonduer (ie me), so I would recommend making life easier by including something more amenable to melting, such as emmental or freiburger vacherin in the mix.

Itoh's Swiss mother-in-law had a secret ingredient up her dirndl sleeve: "One block of the spreadable cheese that comes wrapped in foil triangles in a round cardboard box (eg Laughing Cow). The otherwise icky cheese helps all the cheeses melt together and stay together coherently."

Michelson would not approve, given her firm opinion on the importance of quality cheese: "If you are using Alpine cheeses that have a bit of age on them and are lovely raw milk ones," she writes, "then you have no problem with the flavours and richness coming through. It is only when you skimp on the quality of the cheese that when cooking or melting you will not get the best results."

Yet, thinking along similar lines, she also adds a creamy cheese to her fondue - reblochon may not come in neat little triangles adorned with a jovial cow, but it is indeed rich and wonderfully creamy and it gives her fondue a quite superb consistency.

Her optional extra, blue cheese (for a "a toasty sharp edge"), is less universally popular, however. Testers are split: some feel it simply gives it a shot of savoury flavour, others that it takes over and changes the entire character of the dish. My problem is that for some reason it splits in the pot, too. Perhaps it was too cold when I added it (Michelson recommends the cheese should all be at room temperature), but I'm not risking it again.

If you're not lucky enough to live in the vicinity of a great cheesemonger, then many of these Alpine cheeses will elude you. However, I would recommend going with Michelson's advice: concentrate on quality. Combine one good melting cheese, such as freiburger vacherin (not to be confused with the French vacherin mont d'or) or emmental for texture, with the best member of the gruyère family you can find, whether that be Swiss gruyère or its French relatives beaufort and comté, for flavour, and then add a chunk of creamy reblochon (or raclette, or even taleggio) just before serving to get the perfect texture and flavour.

The other vital ingredient in fondue is wine. Preferably a high-acid Swiss or Savoyarde white of the kind kindly described as "rustic" - not for spurious reasons of authenticity, but because, as This writes in his book Molecular Gastronomy: "Wines that are excessively acidic and, if possible, very fruity … have high concentrations of tartaric, magic and citric acids. Malate, tartrate, and especially citrate ions are very good at chelating (or sequestering) calcium ions. The acidic and fruity wines experts prefer help separate the casein micelles and release their constituent proteins, which stabilise the emulsion by coating the fatty droplets."

In other words, the more acid the wine, the less danger there is of your fondue splitting.

Such wines are available in the UK, but not widely, and like so many Swiss things, they don't tend to come cheap. I would recommend substituting something with high acidity, but not too bold a flavour - picpoul de pinet or Fiona Beckett's suggested muscadet would be better bets than a very herbaceous sauvignon blanc or a rich chardonnay.

Saveur magazine obtained from a Swiss cheesemaker eschews alcohol altogether in favour of double cream. In combination with l'etivaz, "a fruity, floral, raw cow's milk cheese", it's so rich even I can't disgrace myself by eating more than a few mouthfuls.

Wine is definitely not an optional extra here: you need acid to balance the fat of the cheese. If you don't drink (the less strict should note that most of the alcohol will be burned off), or you can only find less acid wines, a squeeze of lemon juice works wonders.

Some recipes call for a pinch of bicarbonate of soda, which is supposed to make the fondue lighter and thus easier to digest. I find it makes it fizz alarmingly - call me old fashioned, but fizzy cheese scares me.

This describes stabilising the fondue with flour "or any other ingredient containing starch, such as potatoes" as a "heretical practice" - but it does considerably reduce the risk of it separating.

Chef Willie Prutsch, whose fondue so impressed food writer David Lebovitz, uses it , as did Itoh's late mother-in-law - even Michelson admits it is useful for ensuring a really smooth finish when catering for a crowd.

You don't need it if you're careful, but if you're wooing a perfectionist this winter and want to cut any risk out of the equation, I would recommend adding 2 tsp to the white wine, as Prutsch does, rather than whisking it in at the end as Itoh does. It's also worth keeping some on hand, whisked into a little cold water, in case your fondue splits.

Traditionally, garlic is wiped around the base of the pan to give the entire dish a subtle hint of its flavour, although Prutsch adds it, finely chopped, to the mixture itself, and the recipe from the Valais cooks it with onion and tomato before adding the cheese. This, in combination with the oregano they also recommend, makes their fondue taste like low-carb pizza.

As I find it easier to make the fondue in a pan and then transfer it to the fondue pot for serving, I'm going to break with custom and add garlic to the cheese itself, so it doesn't get lost in the move, but if you keep it in the same pot, by all means do the wipe around instead.

Michelson adds nutmeg to her mixture, which works wonderfully with cheese, especially if you also go for a slug of kirsch, or morello cherry brandy (NB not the sticky pink cherry brandy; the clear kind you might have hanging around after making black forest gateau , for example).

The testers argue about its merits: it adds a certain nutty sweetness that most like, but some feel, like Lebovitz, "that to be honest, as much as I love kirsch in lots of things, I preferred the fondue without it", so it's very much an optional extra.

Although fondue isn't hard to make, it can be temperamental if you don't show it enough love and attention. Professionals, and native Swiss, may be able to chuck everything in together and end up with perfection, but Michelson's method, stirring the cheeses in gradually, starting with the good-tempered emmental, is much safer for the rest of us. I also like to use a silicone whisk, rather than a wooden spoon for stirring, as I find it covers more ground and leads to a more successful emulsification.

In the case of the Saveur fondue, "chunks of soft white bread are stirred right in, so it's best eaten with spoons, rather than traditional fondue forks", but soggy bread makes me feel queasy, especially when it gets lost at the bottom of the pot, so I prefer the more common practice of dipping your own pieces.

Men who lose a piece are traditionally supposed to buy a round of drinks; women must kiss everyone at the table. Who said old-fashioned romance was dead?

Cheese fondue is usually served with cubes of bread, boiled potatoes, charcuterie and cornichons or other pickles, alongside white wine, kirsch or hot tea to l essen its leaden effect on the stomach . Milk of magnesia is an optional extra.