Slippery rice noodles are first bathed in a slow-simmering broth of laboriously peeled river snails. Then they're topped with odorous bamboo shoots that have been covered in salt and left to ferment for a few weeks, tofu and salty lemon vinegar.

While the snail may stand out as the most unusual ingredient in luosifen, local bamboo shoots are what give soul to the noodle soup. Luosifen's arguably off-putting scent comes from fermented "suan sun" —sour bamboo shoots. Despite being produced in a factory, every bamboo shoot packet sold with luosifen is handmade according to Liuzhou traditions, say manufacturers.

As the bamboo shoots are stored in a pot of mountain spring water for two weeks, they develop a particularly pungent smell during this fermenting process. While the lovers say the pickled bamboo shoot is the soul of the noodle, the haters say it makes the neighbor suspect there is a secret weapon of mass destruction.

What arrived was a colorful, inviting bowl of noodle soup with a reddish-brown, slightly opaque broth filled with a mélange of toppings that provided a symphony of textures and tastes.

Stalks of barely-cooked yu choy added fresh, verdant flavor; salted, skin-on roasted peanuts provided crunch and toasty, umami notes; pickled turnips brought crispness and tangy flavor; wood ear mushrooms had a more subtle al dente texture, with a hint of earthy flavor; tofu skin added delicate flavor and texture; half an egg added heft; and squares of fried tofu soaked up the broth like sponges, bursting with each bite.

The broth was simultaneously spicy, pungent, earthy, sour, and funky, while allowing the flavor of all the toppings to shine through. The silky, slippery round rice noodles, just a little thicker than spaghetti, were a welcome reprieve from the robust flavors while adding another dimension of texture.

The snails are not visible in luosifen. As the snail meat is slowly cooked with pork bones and 13 spices, it melts and becomes part of the soup.

Its distinctive odour, like that of durians, is so strong that it can fill an entire restaurant and the surrounding streets with its smell. However, the smell does not at all affect its popularity among fans whose motto is: "it smells bad, but it tastes delicious".

Just like the notorious durian fruit, this snail-based rice noodle soup dish has created a buzz on Chinese social media thanks to its infamous smell. While some claim the scent is mildly sour, others say it should be classed as a bioweapon.

In 2020, online influencers with tens of millions of followers began blogging about the disgustingly good snack. A combination of online guerilla marketing and word-of-mouth hype has made snail noodles an instant hit. Last year, dozens of snail noodle brands sold 1.1 billion packets of the make-it-at-home version.

Government efforts have led to more research and upgraded technologies in food prep, processing, sterilization and packaging. Nowadays, most luosifen packages on the market have a shelf life of up to six months, which allows people, near or far, to enjoy the same flavors with minimal preparation.

As this year witnessed soaring demand for convenient meals, luosifen became the top stay-at-home food in China. Unlike instant noodles with boring seasoning, luosifen contains as many as nine packets with real ingredients. Some even have crisp radish and eggs. In Asian supermarkets overseas, luosifen also became a hot commodity.

Rather than adding flavoring powders, the luosifen broth—often condensed in packets—is created through protracted cooking processes, with bulks of snails, chicken bones and pig marrow bones sitting in rolling boils for more than 10 hours.

The elaborate process also applies to the rice noodles—the main character of the dish. From grinding grains to steaming to drying to packaging, it takes at least seven procedures carried out over two full days—already a largely shortened time thanks to automation—to achieve the foolproof "al dente" state.