The Story of Khar

An Assamese meal has an order, and the order is a taste. Khar comes first — a small portion, eaten with plain rice before anything else reaches the plate. Tenga, the sour dish, comes last. Everything else sits between those two poles. Serve them the other way round in an Assamese household and someone will notice, and say so.

Khar is not a dish so much as a category. There is khar with fish head and raw papaya, khar with pulses, khar with the tender core of a banana plant. What they share is not an ingredient but a reagent: kolakhar, an alkaline liquid filtered from the ash of sun-dried banana peel.

It is made at home, in quantity, and stored. Ask three households for the recipe and you will get three answers, all of them confident, none of them written down.

Alkaline cooking is not rare globally — nixtamalisation in Mexico, lye rolls in Germany, kansui in Chinese noodle-making, lutefisk in Scandinavia. It is rare in India. Assam is close to the only place on the subcontinent where an alkali is a routine, named, celebrated part of the domestic repertoire.

The likeliest reason is availability. The banana plant grows everywhere in the Brahmaputra valley, produces enormous quantities of biomass, and is already burned as waste. Ash from that biomass is rich in potassium carbonate. Steep it in water, let the solids settle, filter the liquid, and you have a usable alkali at no cost whatsoever.

The bhim kol variety is the one most often named as the source of the best kolakhar, though households use whatever banana they have. Some also make a stronger form from the ash of the whole dried plant rather than the peel alone.

What I could not establish — and I looked — is when the practice started. Domestic techniques of this kind rarely leave a record. They are too ordinary to write down.

The traditional preparation has almost nothing in it, which is the point. Aromatics compete with the alkali rather than supporting it, so they are left out.

This is where the research paid off, because almost everything khar does has a straightforward explanation once you stop treating it as folklore.

Alkali attacks pectin. Plant cell walls are held together by pectin, and raising the pH breaks it down far faster than heat alone. That is why papaya in a khar goes tender in eight minutes when the same cubes in plain water would take twenty, and why it goes slightly translucent rather than simply soft.

Alkali also raises protein pH away from its isoelectric point, which increases water-holding capacity. In practice: the fish stays moist and takes on a slightly springy, almost gelatinous surface. It is the same principle a Chinese kitchen uses when it velvets meat with bicarbonate — arrived at independently, from banana ash, several thousand kilometres away.

And alkaline conditions accelerate Maillard browning, which is a large part of where khar’s savoury roundness comes from. It is not a flavour that was added. It is a flavour the pH made possible.

The soapiness that ruins a bad khar is saponification — the alkali reacting with the fat in the pan. Too much kolakhar and you are, quite literally, making a small amount of soap in your dinner.