How to Choose a Kimchi Container: Onggi to Plastic
Most English-language writing about kimchi tells you how to make it and how to keep it. Very little tells you what to put it in, and almost none of it cites a source you can check. This guide is about the kimchi container itself — how to choose one. Three things decide it: what the vessel is made of, what its lid does, and how big it needs to be.
Table of Contents
- What Is a Kimchi Container, and How Is It Different From an Ordinary Food Container?
- Why Korean Kitchens Treat the Kimchi Container as Equipment
- From Onggi to Plastic: How Korea’s Kimchi Vessel Changed
- Onggi, Glass, Food-Grade Plastic, or Stainless: Which Material Should You Choose?
- What an Inner Press Lid Actually Does
- What Size Kimchi Container Do You Need?
- What Goes Into the Container Besides Baechu-Kimchi
- How Kimchi Containers Compare With Fermentation Crocks Elsewhere
- Frequently Asked Questions
- Pick the Vessel Before You Pick the Recipe
What Is a Kimchi Container, and How Is It Different From an Ordinary Food Container?
A kimchi container is not a lunch box that happens to have kimchi in it. The food inside is alive when it goes in and stays alive afterward. Kimchi is made by lactic acid fermentation, and the organisms doing that work — Lactobacillus and Leuconostoc — are anaerobes, producing carbon dioxide as they go.
That gives the vessel three jobs at once.
It has to hold liquid. Kimchi makes its own brine, and that brine is salty, acidic and staining — the seal keeps it off the refrigerator shelf.
It has to cope with gas. Carbon dioxide is a normal product of kimchi fermentation, and it keeps being produced after the lid goes on.
And it has to keep the kimchi down. Submersion is what maintains the oxygen-free conditions the fermenting bacteria favor, so a container that lets the top layer ride above the liquid is working against the food it holds.
Those three jobs are the whole of this guide. How sour it eventually becomes is covered separately, in the stages kimchi passes through as it sours.
Why Korean Kitchens Treat the Kimchi Container as Equipment
In a kitchen that buys kimchi by the tub, a container is packaging. In a kitchen that makes it, the container is equipment, and the reason is volume.
Kimjang (김장) is the late-autumn season when Korean households put up their winter kimchi. UNESCO’s inscription describes communities making and sharing it in bulk, so that every household has enough to last the winter. A household planning around that is not choosing one box. It is choosing a set.
How much of this still happens varies by household and by region. Some families put up a winter’s worth in a single weekend; others buy their kimchi and keep one container going. An apartment kitchen and a country house with yard space are not solving the same problem.
What does not vary is the hardware problem underneath. The kimchi keeps working after the lid goes on, and the vessel decides how well that goes — which matters, given what fermentation does to kimchi’s nutrition. For the season itself, see our guide to kimjang, the late-autumn communal kimchi-making.
From Onggi to Plastic: How Korea’s Kimchi Vessel Changed
Korea has been fermenting food in earthenware since at least the fourth century: a mural in Anak Tomb No. 3, dated AD 357, shows fermentation vessels.
Onggi (옹기) — Korea’s traditional glazed earthenware fermentation jars — were not chosen for their looks. Onggijang (옹기장), the craft of making Korean onggi earthenware, was designated National Intangible Cultural Heritage of Korea in 1990. On Korea’s national heritage register, the official English name is Onggijang (Earthenware Making).
A 2023 study by Georgia Institute of Technology researchers added a measurement of how the material works. Onggi walls are porous, with pores averaging five micrometers: carbon dioxide moves out, some oxygen moves in, and particles larger than the pores are blocked. Writing in the Journal of the Royal Society Interface, the team put the porosity at 4.72 ± 0.16 percent. The consequence is mechanical rather than magical: gas leaves through the wall, a slight positive pressure inside pushes outward continuously, and that outflow acts as a safety valve, keeping contaminants out without any moving parts.
In a controlled Georgia Tech experiment, salted cabbage fermented in onggi produced about 26% more carbon dioxide than the same cabbage in a sealed glass jar. That comparison ran for two days, in a laboratory, with salted cabbage rather than fully seasoned kimchi. It is a measurement of a material, not a verdict on the containers sold today.
The same reasoning governs Korea’s other ferments: doenjang (된장), Korea’s fermented soybean paste, is still fermented in onggi jars. The jangdok (장독) tradition — the earthenware crocks Korea’s pastes age in — grew up around the same material. Some brewers still age makgeolli (막걸리), Korea’s milky rice wine, in onggi. For the jars themselves, take a closer look at Korea’s breathing jars.
None of which means you need one. USDA home-fermentation guidance is explicit that food-grade plastic and glass containers are excellent substitutes for stone crocks. That one sentence turns a very old vessel into a set of specifications a modern container can meet today.
Onggi, Glass, Food-Grade Plastic, or Stainless: Which Material Should You Choose?
Four materials turn up in Korean kitchens, and the honest way to compare them is by what someone will actually stand behind. Product listings talk about odor barriers and vacuum seals, none of which you can verify from the outside. What you can verify is what home-fermentation authorities say about materials, and what a laboratory measured in earthenware.
| Material | What it does well | What to watch for |
|---|---|---|
| Onggi (옹기) | Porous walls vent fermentation gas and block particles larger than the pores; the vessel Korea has traditionally fermented in | Heavy and breakable, and porous by design rather than airtight |
| Glass | Non-reactive and transparent, so the brine line is visible without opening | Mason jars are workable; the USDA’s spoilage caution is written for sauerkraut in jar-sized batches |
| Food-grade plastic | Light, stackable, and made in a wide range of household sizes | Confirm it is genuinely food-grade — USDA guidance is blunt about this: food must contact only food-grade plastics, never garbage bags or trash liners |
| Stainless steel | Sturdy, opaque and dent-resistant | Metal is generally not recommended for fermenting; high-grade commercial stainless is the stated exception |
Those judgments come from the Royal Society study for onggi’s porosity, USDA guidance for glass and plastic as crock substitutes, and Virginia Cooperative Extension for the metal caution.
Two of those rows deserve another sentence.
Mason jars are the default advice in English-language fermenting guides, and they do work. The USDA’s caution here is written for sauerkraut: fermenting sauerkraut in quart and half-gallon Mason jars is an acceptable practice but may result in more spoilage losses. A kimchi batch runs into the same limits.
Stainless steel needs a caveat, because Western fermenting guidance is cautious about metal. Virginia Cooperative Extension puts ceramic crocks and plastic containers in the suitable column, and notes that metal — except for high-grade commercial stainless steel — can degrade and pit. The exception is real, but it is an exception, and "high-grade commercial" is not printed on the lid.
The longer a batch is meant to last, the more the material matters. Kimchi destined to become mukeunji (묵은지), kimchi aged for months rather than weeks, sits in its own liquid far longer than a batch you empty in two weeks, which is where the caution earns its place.
What an Inner Press Lid Actually Does
This is the part of a kimchi container that does the most work and gets the least attention.
Start from the requirement. Fermentation happens without oxygen, and vegetables stay in that state by staying under liquid. Virginia Cooperative Extension puts it plainly: submersion keeps the product under anaerobic conditions that favor the growth of lactic acid bacteria and other fermenting organisms.
Now look at how you are told to get there. The USDA-derived guidance on suitable containers, covers and weights is refreshingly physical. After the prepared vegetables and brine go in, set a suitably sized dinner plate or glass pie plate inside the container, and weight it down with two or three sealed quart jars filled with water. A plate and some jars of water — that is the traditional apparatus.
An inner press lid is a flat disk that drops inside a kimchi container and holds the kimchi under its own juices. It is the plate-and-weight apparatus built into the container, so there is no stack of water-filled jars on top. Once you see it as a plate plus a weight, the things worth checking become obvious. Does the container have one at all? Does it still reach the surface when the container is only partly full? Can you lift it out with wet hands?
The guidance behind that plate was written for cabbage kept one to two inches under brine. Kimchi is packed differently. It is salted, drained and seasoned rather than submerged in a separate brine. The coarse Korean sea salt that draws water out of the cabbage is what gives it liquid to sit in at all. The same principle still applies: press it down so its own juices cover the surface.
One more thing follows from the gas. It keeps coming after the lid is closed, so a container filled to the brim has nowhere to put it. Leave headspace above the press lid.
What Size Kimchi Container Do You Need?
Capacity is the one question with a published answer.
USDA home-fermentation guidance calls for one gallon of container capacity for every five pounds of fresh vegetables. The same document gives a worked example: a five-gallon stone crock is an ideal size for fermenting about twenty-five pounds of fresh cabbage or cucumbers. Converted to the sizes on the box, that comes out like this:
| Fresh vegetables | Container capacity |
|---|---|
| 5 lb (about 2.3 kg) | 1 gallon (about 3.8 liters) |
| 10 lb (about 4.5 kg) | 2 gallons (about 7.6 liters) |
| 25 lb (about 11.3 kg) | 5 gallons (about 19 liters) — the crock size USDA guidance calls ideal |
Two adjustments before you buy. First, that ratio comes from guidance written for sauerkraut and pickles, where vegetables sit submerged in a separate brine. Kimchi is salted and drained first, so the same weight of cabbage takes up less room than the raw figure suggests; read the ratio as a ceiling to size against, not a target to fill. Second, subtract headspace: gas needs somewhere to go, so the capacity you buy is never the capacity you pack.
If you are working from a batch rather than a number, a from-scratch napa cabbage kimchi recipe will tell you how many heads of cabbage you are dealing with. Size up from there.
The last constraint is not the kimchi at all. It is the shelf. A container has to fit where it will sit — a refrigerator shelf, or in many Korean homes a dedicated kimchi refrigerator. That limit often decides capacity before the arithmetic does. How kimchi is kept day to day, including Korea’s kimchi refrigerators, is its own subject.
What Goes Into the Container Besides Baechu-Kimchi
What you pack changes what you should buy.
Baechu-kimchi (배추김치), the cabbage kimchi most households pack by the tub, is packed as whole cabbage halves, so it wants width and depth rather than a narrow neck. A jar opening you cannot get a cabbage half into — or back out of — is the wrong shape however good the seal is.
Kkakdugi (깍두기) — cubed radish kimchi — is the opposite geometry. The pieces are small and pack tight, and radish gives up a great deal of liquid, so the level rises faster than you expect. Headspace matters more here.
Mukeunji, the batch you keep for months, is where that material caution matters most.
Beyond kimchi, the same rules travel: cucumber pickles and other salted vegetable ferments are exactly what the USDA guidance was written for, so a vessel that meets that standard will handle them too.
How Kimchi Containers Compare With Fermentation Crocks Elsewhere
Home fermenting outside Korea usually starts with a stone crock, and the guidance that comes with it describes a two-part system: the crock holds the vegetables, and a plate weighted with water-filled jars holds them under the brine. Vessel and weight are separate objects you assemble yourself.
The Korean kimchi container solved the same problem by combining them. The press lid is the plate and the weight, moved inside the container and sized to it — which is possible partly because of what kimchi is. A crock ferment sits in a brine you mix and pour over it; kimchi sits in liquid the salt drew out of the vegetables themselves. Less liquid to manage, and the thing doing the pressing can be lighter.
Neither arrangement is better than the other. They answer the same physical requirement — keep it under the liquid, let the gas out, keep everything else from getting in — in kitchens solving for different volumes and foods.
Frequently Asked Questions
What kind of container should I use for kimchi?
Use a kimchi container that is food-grade, seals well, and lets you press the contents under their own juices. The USDA puts food-grade plastic and glass in the same class as a traditional stone crock. Korean onggi earthenware works for the same reason: it manages liquid and gas.
What size kimchi container do I need?
USDA guidance calls for one gallon of capacity — about 3.8 liters — for every five pounds (roughly 2.3 kilograms) of fresh vegetables. Kimchi is salted and drained first, so it packs smaller than that ratio implies. Leave headspace for carbon dioxide, and check the container against the shelf it will sit on.
Can I use a glass jar or a Mason jar for kimchi?
Yes. Glass is one of the two materials the USDA names as a stand-in for a stone crock. That same source adds a caveat about jar-sized batches: fermenting sauerkraut in quart and half-gallon Mason jars is an acceptable practice but may result in more spoilage losses. Size a large batch accordingly.
Do I need an onggi to make good kimchi?
No. Onggi (옹기) — Korean earthenware fermentation jars — have porous walls that vent fermentation gas, a property measured in a laboratory, not a marketing claim. But USDA guidance puts food-grade plastic and glass on equal footing with a stone crock, and a working press lid matters more than the material.
Pick the Vessel Before You Pick the Recipe
A kimchi container is a simple object with a specific job. The three decisions behind it barely change: a food-grade material you can trust, a lid that presses the contents under their own juices, and enough capacity for the batch plus the gas it will make. Most of what is printed on the packaging is decoration around those three.
Buy for the batch you will actually make. If that batch has not happened yet, start on the eating side instead. Bossam (보쌈), the steamed pork eaten with freshly made kimchi, is a persuasive argument for making your own.
Share this guide with anyone who has been meaning to make kimchi and has been putting it off over the hardware.
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