Bun oc, the snail bowl Hanoi eats sour

Bun oc is the Hanoi bowl most visitors walk past. Snails from a paddy field in a tomato broth turned sour with rice vinegar, sold before noon and gone by two.

What is in a bowl of bun oc?

Snails, first — freshwater apple snails, boiled, picked from the shell and returned to the bowl whole. The broth is tomato and stock, soured with giam bong, a mild fermented rice vinegar, and seasoned with fish sauce. Two or three tomatoes go into a litre of it.

On top go rice noodles, cubes of fried tofu, spring onion and a great deal of herb. Tia to, perilla, does more work here than anywhere else in Vietnamese cooking. Some counters add a slice of cha, the steamed pork sausage.

What do the snails actually taste like?

Firm, faintly mineral, and closer to a clam or a whelk than to anything a European snail menu offers. They are not slimy, they are not garlicky, and they carry the broth rather than flavouring it.

A bowl runs 35,000 to 60,000 dong and carries eight to twelve snails. The texture is the part that decides people. It is a clean chew, like a small piece of squid, and a bowl is usually eight to twelve of them rather than a heap. Anyone who eats snails by the plateful at night in Saigon will recognise them immediately.

How is it different from bun rieu?

The two share a broth and differ in what is in it. Bun rieu is built on crab paste, which is whisked into the pot and sets in soft orange clots on the surface.

Bun oc has snails and nothing whisked. Many counters cook both from the same tomato base and sell a mixed bowl, bun oc rieu. That is the order to make if you cannot choose. The noodle soups guide places both against the rest.

Where do the snails come from?

Paddy fields, ponds and the edges of the Red River delta, where apple snails are gathered by hand or trapped. They are a pest in a rice field and a crop in a kitchen, which is the sort of arrangement Vietnamese cooking is full of. A kilo of shells yields perhaps 150 g of meat.

The snails arrive at a counter alive, are boiled in batches, and the meat is twisted out of the shell with a pin or a thorn before service. That is an hour of work for a morning's bowls, which is why a stall that does bun oc properly rarely sells anything else.

What hours does the pot last?

Morning, mostly. Counters open at 6 and the pot is finished by 1. A counter that opens at six is usually cleaning up by one, which is the standard rhythm described in the breakfast guide.

The summer variant is bun oc nguoi. The same snails and noodles come cold and dry, with the sour broth in a cup on the side to sip and spoon. In August that is the better order.

Which Hanoi counters sell it?

Hanoi, where it belongs. The Old Quarter and the lanes off Hoe Nhai and Hang Chieu have counters that have sold nothing else for decades. It travels to Hai Phong and Ninh Binh and thins out further south.

Saigon has bun oc and it is a different dish there, sweeter and often with coconut, and a bowl runs 10,000 to 20,000 dong more. Neither is wrong; the northern one is the original and the sour one.

Should you be careful with it?

Use the usual rules and no special ones. The snails are boiled hard before they are picked and the broth is held at a simmer. A busy counter turns its stock over in a morning.

What is worth a look is the herb plate, as it always is, and the street food safety guide covers where the real risks sit. Snails from a slow counter at the wrong hour are the one thing worth avoiding, which is an argument for going before ten.

What do you say at a bun oc counter?

Say bun oc and hold up fingers for how many bowls. Useful words: them oc for more snails, khong tofu if you do not want the fried cubes, and bun oc nguoi for the cold version.

Chilli, vinegar with sliced chilli in it, and a dish of shrimp paste sit on the table. The vinegar is the one to reach for: a spoonful sharpens the broth, which is the direction this bowl is meant to go.