Storage and shelf life

Keeping kimchi: how long, where, and why it fizzes

Our kimchi is raw and unpasteurised, so the lactic cultures are still alive in the pot and it keeps fermenting after you buy it. That is the point of it — and it is also why it behaves differently from a jar of pickles. Five rules cover everything.

How long does kimchi keep?

Unopened: three months in the fridge at 4 °C or below. The date is on the lid. Opened: weeks, kept cold and under its own brine. Kimchi does not “go off” the way milk does; it goes sour, slowly, and every stage of that is edible. Week one is young and crunchy. A month in, it is deeper and more sour. By month three it is a cooking kimchi — sharp, soft, and exactly what a stew wants.

Trust your nose over the date. Sour, fizzy, a little softer than when you opened it: normal. Fuzzy mould on the surface or a smell that is off rather than sour: rare, and only happens when the cabbage was left sitting above the brine in a warm fridge — throw that pot out.

Why the lid pops and the kimchi fizzes

Lactic fermentation makes carbon dioxide. In a sealed pot the gas builds up, the lid domes a little, and the first time you open it you may hear a hiss and see bubbles rise through the brine. That is fermentation working, not a fault. Open it over the sink the first few days, and press the cabbage back down under the liquid before you close it again.

The fridge, not the counter

Cold is the brake. At 4 °C the kimchi moves through its stages over weeks; on a kitchen counter at 20 °C it does the same in days. We ferment it at room temperature ourselves for seven days before packing, so what you buy is already where it should be — from then on, the colder it lives, the longer it stays young. Never leave the pot out to “warm up”: take what you need with a clean fork and put it straight back.

Keep it under the brine

The liquid in the pot is the kimchi’s own brine, and everything under it is protected. Everything above it dries out and is where trouble starts. After each serving, press the cabbage down so it is covered, wipe the rim, close the lid. Use a clean utensil every time — bread crumbs, butter and yesterday’s rice do not belong in the pot.

Too sour to eat plain? Cook it

The end of a pot is not waste, it is an ingredient. Sour kimchi is what kimchi-jjigae (the stew), kimchi fried rice and kimchi pancakes are built on — the sourness is the flavour, and heat softens it. Cooking does kill the cultures, so eat it raw while it is young and cook it once it has turned. Both are correct.

Can you freeze kimchi?

For cooking, yes: portion it, freeze it, drop it frozen into the pan. The texture will not survive — thawed kimchi is soft — and the cultures are irrelevant once it is cooked. For eating raw, no; buy a fresh pot instead.

Standard and vegan: any difference?

None in how you keep them. The standard version contains seafood, the vegan one is all plant; both are packed on day seven of the same week and both keep three months unopened.