Ingredient

Kimchi

Kimchi is Korean fermented vegetable — most often napa cabbage, salted and then coated in a seasoning paste of chilli, garlic, ginger and usually something savoury and fishy, and left to sour. It is not one dish but a whole category, and it is eaten at more or less every Korean meal rather than as a condiment on the side of an occasional one.

What it is, and what it is not

The English-language shorthand — "spicy fermented cabbage" — is true of the commonest kind and misleading about the category. Kimchi is made from radish, cucumber, spring onion, mustard leaf and a good deal else, some versions carry no chilli at all, and some are barely fermented and eaten fresh within a day.

What makes something kimchi is the process rather than the vegetable: salt it, season it, let lactic acid bacteria work on it. The version most people outside Korea mean is baechu kimchi, made with napa cabbage, and it is the one this page is mostly about.

The seasoning is what separates it from sauerkraut. Kraut ferments plain and tastes of soured cabbage; kimchi is coated before it ferments in a paste that typically carries gochugaru (Korean chilli flakes, more fruity and smoky than hot), garlic, ginger, spring onion, and a source of savouriness — salted shrimp, fish sauce, or in vegan versions kelp stock and soy. It ferments with all of that in it, so the acid and the seasoning develop together.

How the flavour changes with age

This is the thing nobody tells you and it matters more than any other fact about kimchi: fresh kimchi and old kimchi are different ingredients with different uses.

Fresh, in the first few days, it is crunchy, salty, sharply seasoned and barely sour. It works as a raw side dish and a foil to rich food.

Ripe, after a couple of weeks in the fridge, the acid has come up, the raw garlic edge has softened, the cabbage has gone translucent at the base and the flavour is deep and rounded. This is the peak for eating cold.

Sour, after a month or more, it is properly acidic, softer, and fizzy on the tongue. It is past its best raw — and it is exactly what the great cooked kimchi dishes are made from. A jar you think has gone too far has in fact just become the correct ingredient for something else.

How to use it

• Cold, as a side dish, in small quantities beside rice and grilled meat. Fresh or ripe, not sour.
• **In a stew — kimchi jjigae.** Sour kimchi, pork belly or tuna, tofu, its own juice, and a little stock. The single best use for a jar that has gone too acidic to eat raw.
• Fried rice. Chop it, fry it hard in oil first until the edges caramelise and the raw acid burns off, then add the rice.
• **Pancakes — kimchijeon.** Chopped kimchi and its juice in a thin batter, fried crisp. Again a sour-kimchi dish.
• With eggs, cheese and anything fatty. The acid cuts fat exceptionally well, which is why kimchi toasties and kimchi omelettes work so well outside Korea.
• Do not waste the juice. It is the most concentrated thing in the jar — use it in the stew, in the fried rice, or in a dressing.
• Fry it before you add liquid. Kimchi cooked straight into a wet dish stays sharp and raw-tasting; kimchi fried first goes sweet and savoury.

The things a recipe assumes you know

Gochugaru

Korean chilli flakes. Coarse, bright red, fruity and smoky, with moderate heat. Not interchangeable with cayenne or with generic crushed chilli, both of which are hotter, duller and will make the kimchi taste harsh rather than deep.

Jeotgal / saeujeot

Salted fermented seafood — usually tiny shrimp. It brings savouriness and helps the ferment along. Fish sauce is the common substitute; kelp or shiitake stock plus soy is the usual vegan route, and the result is a little lighter.

Napa / Chinese leaf

The cabbage. Milder, thinner-leaved and more tender than a European white cabbage, with a thick white rib that stays crunchy. A white cabbage version is possible but is a different, tougher thing.

The salting stage

Cabbage is salted and rested before the paste goes on, then rinsed. This draws out water so the finished kimchi is not watery and the leaf stays crisp. Skipping it is why home kimchi ends up limp and dilute.

Fizz

Carbon dioxide from the fermentation. A jar that hisses when opened is working, not spoiled. Open it over the sink.

Buying and keeping it

Most kimchi sold outside Korea is in the chilled cabinet and is alive. It will keep fermenting in your fridge, slowly, for months — which is a feature rather than a shelf-life problem, as long as you understand that what is in the jar in week eight is not what was in it in week one.

Keep the solids under the liquid, use a clean utensil, and expect the jar to build pressure. Bulging lids and a hiss on opening are the ferment working.

The cheapest jars are often heavily sweetened and lightly fermented, and taste more like a spiced pickle than like kimchi. If it tastes sweet and not sour, that is what has happened.

FoodHQ does not publish salt percentages, pH figures or keeping times for home preserving. Those are safety numbers, they are set by a food safety authority rather than by a cookery writer, and the right ones depend on what you are fermenting and where you are. In the UK the Food Standards Agency is the authority — use a recipe from them or from another body with the same standing, and treat this page as the explanation of why that recipe is shaped the way it is.

Making it yourself, in outline

The structural difference from sauerkraut is that the cabbage is salted and then rinsed before the paste goes on.

• Quarter the napa cabbage through the core so the leaves stay attached rather than shredding it.
• Salt or brine it for several hours, until a thick stem bends without snapping.
• Rinse it thoroughly. Most of the salt leaves at this stage, and skipping it gives kimchi nobody can eat.
• Make the paste — gochugaru, garlic, ginger, and a savoury element such as fish sauce, salted shrimp or a seaweed stock.
• Work the paste between every leaf, wearing gloves.
• Pack it tight with headroom. It is vigorous and will push brine out of the jar in the first days.

Common questions