Fermented fish is a base, not a condiment

Eromba is boiled vegetables, mashed with chilli, and it is not a complicated dish. What makes it taste like a dish rather than like mashed vegetables is a teaspoon of something dark and violently fragrant that comes out of a jar. That teaspoon is ngari — fermented fish — and the way to understand Manipuri cooking is to stop thinking of it as a condiment. It is the stock. It is the salt. It is the thing that makes the pot taste built.

Here is the fact that reorganises the whole cupboard: Manipur does not catch the fish. Ngari is made from Puntius sophore, the pool barb, five to ten centimetres long, and the dried fish comes in by the truckload from the Brahmaputra valley — Karimganj district in Assam — and from Bangladesh. It is bought in the dry months, October to January, sorted by size, and stored in sacks until a producer is ready to pack a pot. A landlocked state whose most important seasoning is imported is not an oddity; it is the reason the seasoning exists in the form it does.

Why a paste and not a fish

Fresh fish is the most perishable protein a household can hold, and the hill states are a long way from the water that produces it. Everything about ngari follows from that distance. A small fish with a high surface-to-volume ratio dries fast in the sun, and dried it can travel for weeks without spoiling. But dried fish is a poor food: bony, hard, tasting of nothing much. Fermented, it becomes the opposite — a concentrate so strong that a spoonful seasons a pot, and so stable that a sealed pot keeps for a year.

The pot is the machine that does the conversion, and it is worth describing because it is designed around a single problem: keeping air out without using salt. The vessel is a wide earthen pot called a kharung. A new one is coated inside with mustard oil eight to ten times, with a week to ten days between coats, until the clay is saturated and stops being porous; an old pot needs only one coat. The dried fish is washed, drained overnight, then pressed — traditionally by foot, through a sack — until the heads and bones break and the oil in the fish comes out. It is packed into the pot under pressure until the pot is full to the neck, and then sealed: a layer of fish scales or polythene, an oil slurry, mud, and a cow-dung slurry over the top. Then it goes into a dark room and stays there for four to six months.

What the bacteria are doing

There is no starter culture and no salt, so the fermentation is carried by whatever is on the fish and in the pot, working under conditions that exclude the organisms that need oxygen. The bacteria that dominate are lactic acid bacteria of the kind found in most traditional ferments, together with bacilli and micrococci, and the yeasts come along for the ride. What they do to the fish is not pickling. A pickle is preserved by acid, and there is no acid here to speak of; the pH does not fall the way a brine pickle's does. What is happening instead is proteolysis — the proteins are being taken apart into peptides and free amino acids.

That is the whole point, and it is why the smell is so specific. Glutamate and the other free amino acids are what "savoury" chemically is; a fish that has been broken down this far tastes of far more than a fish, in the way that a stock tastes of more than the bones in it. The ammonia edge people find difficult is a by-product of the same process, and the traditional answer to it is not to fight it but to use less: a teaspoon, stirred into boiled greens, where it reads as depth rather than as fish.

The region has a smaller version of the same idea. Hentak is made from a different, smaller fish, dried and crushed to powder, mixed with an equal weight of crushed taro petiole, and fermented for about two weeks into a paste that keeps as balls. Same logic, shorter distance, faster clock. And on the plains of Assam the same fish is dried and fermented into shidol, in Tripura into berma, in Sikkim and the Darjeeling hills into sidra — one technique with a dozen local names, all of them a way of turning a cheap, perishable, small fish into something that can sit in a kitchen for a year.

The exchange rate

Think about what a base ingredient usually is. Fish sauce is made from a glut of anchovies at the coast. Stock is made from bones that would otherwise be thrown away. Soy sauce is made from a bean so cheap it was used as a tax payment. A base is normally a way of dealing with abundance. Ngari is a way of dealing with scarcity: the fish is imported, so it is dried to travel, so it is fermented to concentrate, so it is dosed by the spoon. Every step is a response to the previous step's constraint, and the result is a cuisine whose flavour is manufactured rather than grown.

That is the difference you can taste between an eastern kitchen and a southern one. A Tamil dish is seasoned: salt, tamarind, chilli, curry leaf, each added at a chosen moment, each doing one job. An eromba is assembled: one ingredient already contains the salt, the savoury note and the fermented edge, and the cook is adjusting a single variable. It is closer to the way a Western kitchen uses a stock cube or a dash of Worcestershire — except that here the cube is the cultural centre of the cuisine rather than a shortcut inside it.

The base is now the fragile part

A concentrate made by a spontaneous fermentation in a clay pot, with no added salt, is a difficult thing to scale, and the pressure on it is now visible. A 2015 study of the fishery reported that the pool barb population has been falling, under commercial fishing pressure and pollution around Loktak Lake, which is where much of the local catch comes from. Adulteration has been reported in the trade: urea added to a batch to speed the fermentation up, which is exactly what you would expect of a product with months of waiting built into its price and no laboratory at the door. The state responded by licensing production units and applying the Food Safety and Standards Act to them, which makes ngari one of the few traditional ferments in India with a formal compliance obligation.

None of that has changed what the jar is for. A family in Imphal still buys ngari by the packet, keeps it in a bottle with a tight lid, and puts a teaspoon of it into the greens; the smell gets into the fridge and stays there for a day. What is worth carrying away is the causal chain, because it repeats: the fish had to come from somewhere else, so it came dried, so it was fermented to concentrate it, so it is used by the spoon, so the kitchen tastes built rather than seasoned. You can read the map off the flavour. The reason the food tastes the way it does is not the recipe. It is the distance.

This is entry 14 of Food in About India. The pillar's argument — grain, fat and what a place could not get — is set out on the pillar page.