What Is Kimchi? A Complete Guide to Korea’s Fermented Food

Kimchi is a traditional Korean food made by salting, seasoning, and often fermenting vegetables.

Napa cabbage is the best-known type, but kimchi can also be made with Korean radish, cucumber, green onion, mustard greens, and other vegetables.

Kimchi does not have one fixed flavor. Depending on the recipe and fermentation stage, it may taste crisp, savory, garlicky, spicy, refreshing, tangy, or sour.

It is also more than one dish. Kimchi is a large group of Korean foods shaped by regional traditions, seasonal ingredients, household recipes, and different fermentation methods.

Kimchi at a Glance

What Is Kimchi Made Of?

Kimchi is made with vegetables, salt, and seasonings. The exact ingredients depend on the type of kimchi and the recipe.

Napa cabbage is the vegetable most people recognize. Korean radish is also widely used, especially in cubed radish kimchi, called kkakdugi.

Other types may use:

• Cucumber

• Green onion

• Mustard greens

• Young radish

• Perilla leaves

• Chives

• Other seasonal vegetables

The vegetables are usually salted or soaked in brine before the seasoning is added.

Kimchi recipes may combine vegetables, salt, garlic, ginger, green onion, gochugaru, and other savory ingredients.

Common seasonings include:

• Gochugaru, or Korean red pepper flakes

• Garlic

• Ginger

• Green onion

• Radish

• Salt

• Fish sauce

• Salted shrimp

• Other fermented seafood

• Plant-based savory ingredients

There is no single ingredient list for all kimchi.

Recipes can change by family, region, season, vegetable, and desired flavor. Many red kimchi recipes use Korean red pepper flakes, but not every kimchi contains red pepper.

Some recipes use fish sauce or salted seafood to create a deeper savory taste. Other recipes use only plant-based ingredients.

People with seafood allergies and those following vegan or vegetarian diets should always read the full ingredient list. Kimchi made mainly with vegetables is not always vegan.

Is Kimchi Fermented?

Many types of kimchi are fermented, but kimchi can be eaten at different stages of fermentation.

Kimchi fermentation usually begins with microorganisms naturally found on the vegetables and other ingredients. As fermentation continues, lactic acid bacteria become more active. These bacteria help change the food’s acidity, aroma, texture, and flavor.

A review published in Applied Microbiology and Biotechnology explains that kimchi fermentation involves changing groups of microorganisms, including lactic acid bacteria. The ingredients, salt level, temperature, and storage conditions all affect this process.

The basic method usually includes:

1. Preparing and cutting the vegetables

2. Salting or brining them

3. Rinsing or draining them, depending on the recipe

4. Mixing them with seasonings

5. Packing them into a container

6. Allowing fermentation to begin

7. Refrigerating the kimchi to slow the process

Salt has several important jobs. It seasons the vegetables, pulls out moisture, changes the texture, and helps create the right conditions for fermentation.

Traditional kimchi does not always need a commercial starter culture. Research has found that vegetables and seasoning ingredients can naturally carry some of the bacteria involved in fermentation.

Refrigeration slows fermentation, but it does not always stop it completely. Kimchi may continue to become more sour and aromatic while stored in the refrigerator.

What Happens During Fermentation?

During fermentation, microorganisms use sugars and other carbohydrates found in the ingredients. This creates organic acids, gases, and flavor compounds.

Research on kimchi fermentation has found compounds such as lactic acid, acetic acid, and carbon dioxide. These help create kimchi’s sour flavor, aroma, and natural bubbling.

As kimchi ferments, you may notice:

• More sourness

• A stronger fermented aroma

• Better-blended seasoning

• Softer vegetables

• Small bubbles

• Gas or pressure in the container

• Brine rising between the vegetables

These changes explain why young and aged kimchi can taste very different.

Temperature affects how quickly fermentation happens. Kimchi kept in warmer conditions usually changes faster than kimchi kept cold.

For this reason, kimchi should be stored according to the producer’s refrigeration instructions.

Fresh Kimchi vs. Fermented Kimchi

Fresh kimchi is usually crisper and more vegetable-forward. Longer-fermented kimchi is often softer, more sour, and deeper in flavor.

Fresh kimchi is usually crisp and bright, while longer fermentation creates deeper acidity and a softer texture.

Fresh or lightly fermented kimchi may have:

• Firm vegetables

• A bright garlic and pepper flavor

• Less sourness

• A fresh vegetable taste

• Seasonings that still taste separate

As fermentation continues, kimchi may develop:

• More acidity

• A deeper aroma

• Better-blended seasoning

• A softer texture

• More gas or brine movement

• A stronger fermented taste

Geotjeori is a style made to be eaten fresh or soon after seasoning. It is known for its crisp texture and bright flavor.

Aged kimchi is more sour and often works better in cooked dishes. Its stronger taste can remain noticeable when mixed with rice, broth, noodles, tofu, or meat.

Choose the fermentation stage based on how you plan to use it:

• Choose fresh kimchi for crunch and brightness.

• Choose moderately fermented kimchi for a balanced tang.

• Choose aged kimchi for fried rice, stew, pancakes, and other cooked dishes.

What Does Kimchi Taste Like?

Kimchi can taste savory, tangy, garlicky, spicy, salty, crisp, refreshing, or sour.

There is no single flavor that describes every type.

Napa cabbage kimchi often combines crisp cabbage with garlic, ginger, Korean red pepper, and savory seasoning. When it is young, the cabbage may taste fresh and juicy. As it ferments, the flavors blend together and become more sour.

Cubed radish kimchi has a firmer and denser bite. The radish can also release a great deal of juice when eaten.

White kimchi is usually mild, clean, and gently seasoned.

Water kimchi has a light vegetable brine and is often less heavily seasoned than red cabbage kimchi.

The flavor depends on:

• The main vegetable

• The amount of red pepper

• Garlic and ginger levels

• Salt concentration

• Seafood-based or plant-based seasonings

• Fermentation temperature

• Fermentation time

• Storage conditions

One jar cannot represent every style of kimchi.

Is Kimchi Always Spicy?

No. Kimchi does not have to be spicy.

Many well-known recipes contain gochugaru, or Korean red pepper flakes. Gochugaru adds red color, aroma, flavor, and heat.

However, the heat level can vary greatly.

Some red kimchi has only a mild warmth. Other recipes can be much hotter.

Milder types include:

• Baek-kimchi, or white kimchi

• Dongchimi, a type of radish water kimchi

• Other mild household and regional recipes

Kimchi is better described as seasoned or fermented vegetables, not simply spicy cabbage.

Is Kimchi Vegan?

Some kimchi is vegan, but not all kimchi is vegan.

Traditional and commercial recipes may contain:

• Fish sauce

• Salted shrimp

• Anchovy-based ingredients

• Seafood extracts

• Other fermented seafood seasonings

These ingredients can add saltiness and savory flavor.

Vegan kimchi replaces seafood ingredients with plant-based seasonings. Depending on the recipe, these may include mushrooms, sea vegetables, vegetable broth, or other savory ingredients.

The best way to know whether kimchi is vegan is to check:

1. The full ingredient list

2. The allergen statement

3. The producer’s dietary labeling

The word “kimchi” alone does not tell you whether the product is vegan.

NUF Ingredient Approach

NUF Classic, Vegan, and Cubed Radish Kimchi are made without fish sauce and with no added MSG.

Customers should still review the full ingredient list for each product because the product names may reflect differences beyond one ingredient.

Is Kimchi Raw?

Kimchi often begins with uncooked vegetables, but the words “raw,” “unpasteurized,” and “contains live cultures” do not mean exactly the same thing.

In traditional preparation, vegetables are salted, drained or rinsed, seasoned, packed, and fermented without being cooked first.

However, some commercial products may be heated or pasteurized after fermentation. Heat treatment can reduce or remove live microorganisms.

Someone looking for kimchi with live cultures should check whether the product is naturally fermented and unpasteurized instead of relying only on the word “raw.”

Does Kimchi Have Probiotics?

Naturally fermented, unpasteurized kimchi may contain live lactic acid bacteria. However, this does not mean every kimchi is a proven probiotic product.

Scientists have found several groups of lactic acid bacteria in kimchi, including Leuconostoc, Weissella, and related groups often linked to fermented vegetables.

The types and amounts can change based on:

• Ingredients

• Recipe

• Fermentation stage

• Temperature

• Processing

• Storage

The word probiotic has a more exact meaning than fermented.

A true probiotic claim requires more than the presence of live bacteria. Researchers must identify the microorganisms, confirm that enough remain alive, and show a specific health benefit.

A research review asking whether kimchi deserves probiotic status found that kimchi often contains high levels of lactic acid bacteria. However, the review also explained that more specific evidence is needed for formal product-level claims.

A responsible explanation is:

Naturally fermented kimchi may contain live microorganisms, but the types and amounts can vary. Fermentation alone does not prove a specific health benefit.

Kimchi should not be described as a cure, detox, or replacement for medical care.

Is Kimchi Healthy?

Kimchi can be part of a balanced diet, but it should be considered as part of the whole meal.

Kimchi is mainly made with vegetables. It can add flavor, texture, variety, and fermented-food diversity to a meal.

Depending on the recipe and serving size, it may provide:

• Vegetables

• Dietary fiber

• Vitamins and minerals from its ingredients

• Compounds created during fermentation

• Live microorganisms when naturally fermented and unpasteurized

However, kimchi products may have different:

• Ingredients

• Sodium levels

• Serving sizes

• Fermentation stages

• Processing methods

• Levels of live microorganisms

Kimchi can also contain a fair amount of sodium. People who have been told to limit sodium should watch their portion size and follow guidance from a qualified healthcare professional.

Kimchi should not be treated as a miracle food. It is one flavorful part of a varied eating pattern.

Kimchi vs. Sauerkraut

Kimchi and sauerkraut can both be made with fermented cabbage, but they come from different cultures and usually use different ingredients.

Sauerkraut is generally made by fermenting finely cut cabbage with salt.

Napa cabbage kimchi often uses larger cabbage pieces and may include:

• Garlic

• Ginger

• Green onion

• Radish

• Gochugaru

• Fish sauce

• Salted seafood

• Plant-based savory seasonings

Kimchi is also a much larger food category. It includes radish kimchi, cucumber kimchi, white kimchi, water kimchi, and many other types.

Sauerkraut is usually salty and sour. Kimchi may be spicy, garlicky, savory, crisp, refreshing, or sour.

Neither food needs to be called better. They are separate fermented-vegetable traditions with their own histories and uses.

Why Does Kimchi Bubble?

Kimchi may bubble because fermentation produces gas, including carbon dioxide.

Gas can collect between cabbage leaves, radish pieces, seasoning, and brine. When the container is moved or opened, you may see bubbles or hear a light fizz.

Normal fermentation activity may cause:

• Small bubbles

• Moving brine

• A slight hiss when opened

• Pressure under the lid

• Liquid rising inside the jar

Bubbling alone does not mean the kimchi has spoiled.

To reduce leaks and pressure:

• Keep it refrigerated.

• Store the container upright.

• Do not shake it.

• Open it carefully.

• Keep the intended headspace.

• Follow the storage directions on the label.

Does Kimchi Go Bad?

Yes, kimchi can spoil. However, a more sour taste does not always mean it has gone bad.

Normal fermentation changes may include:

• More sourness

• A stronger fermented smell

• Softer vegetables

• Bubbles or fizz

• More visible brine

• Pressure in the container

• A slow change in color

Older kimchi may no longer taste ideal as a cold side dish, but it may still work well for cooking.

Possible reasons to throw it away include:

• Visible fuzzy mold

• Clear contamination

• A rotten or unusual smell

• A broken or damaged package

• Storage outside the label directions

• Doubt about whether it was handled safely

Always use a clean utensil.

When you are unsure about food safety, do not taste the food to test whether it is safe.

How Long Does Kimchi Last?

There is no single shelf life for every type of kimchi.

How long it lasts depends on:

• Recipe

• Salt and acidity

• Fermentation stage

• Packaging

• Heat treatment

• Refrigerator temperature

• Handling after opening

• The producer’s tested shelf life

It is also helpful to separate two questions.

How long is it safe to eat?

Follow the package date, refrigeration directions, and handling instructions.

How long does it keep the flavor you prefer?

This depends on personal taste.

Some people prefer kimchi fresh and crisp. Others enjoy it after it becomes more sour. Aged kimchi is often saved for cooking.

Do not replace package instructions with one general storage period found online.

How Should Opened Kimchi Be Stored?

Opened kimchi should usually be kept cold, upright, tightly closed, and handled with clean utensils.

Keep opened kimchi refrigerated, upright, tightly closed, and handled with clean utensils.

Follow these steps:

1. Keep the container refrigerated.

2. Store it upright.

3. Close the lid after each use.

4. Use a clean spoon, fork, or pair of tongs.

5. Do not leave it at room temperature for long periods.

6. Keep the vegetables in contact with the seasoning and brine when possible.

7. Do not return leftover food to the container.

8. Follow the storage directions on the package.

A steady, cold temperature helps slow fermentation and protect texture.

How Do You Eat Kimchi?

Kimchi can be eaten as a side dish, topping, condiment, or cooking ingredient.

In Korean meals, it is often served in a small dish beside rice, soup, protein, and other side dishes.

For someone new to kimchi, the easiest first step is to add a small serving to a familiar meal.

A small serving of kimchi can add crunch, acidity, and savory flavor to a balanced meal.

Try kimchi:

• With rice and grilled chicken

• Alongside eggs

• With tofu

• In a grain bowl

• On a sandwich

• On a burger

• In a taco or wrap

• With roasted vegetables

• Alongside dumplings

• Added to noodles

• Chopped into fried rice

• Cooked in stew

• Mixed into a savory pancake

Fresh kimchi works well as a cold side or topping.

Older, more sour kimchi often works better for cooking because its stronger taste remains noticeable when mixed with other ingredients.

Kimchi does not need to take over the plate. A small amount can add crunch, acidity, heat, and savory depth.

What Are the Main Types of Kimchi?

There are many more types of kimchi than the red napa cabbage version often seen in American grocery stores.

Kimchi can be made with cabbage, radish, cucumber, green onion, and many other vegetables.

Napa Cabbage Kimchi

Napa cabbage kimchi, called baechu-kimchi, is the type most widely known outside Korea.

The cabbage is salted and covered with seasoning, often between the leaves. Its texture and flavor change as it ferments.

Cubed Radish Kimchi

Cubed radish kimchi is called kkakdugi.

It is made with cubes of Korean radish and has a firm, juicy bite.

Fresh Kimchi

Geotjeori is made to be eaten fresh or soon after seasoning.

It is known for crisp vegetables and bright flavor rather than strong sourness.

White Kimchi

White kimchi, called baek-kimchi, is made without the heavy red pepper seasoning found in many other types.

It is usually mild, clean, and refreshing.

Water Kimchi

Water kimchi contains a larger amount of seasoned vegetable brine.

Dongchimi is one of the best-known examples and is often made with radish.

Cucumber Kimchi

Cucumber kimchi has a crisp, juicy texture and is often enjoyed as a lighter, fresher style.

Green Onion Kimchi

Green onion kimchi, called pa-kimchi, uses green onion as the main vegetable and often has a stronger aroma and seasoning.

These types show why kimchi should not be described only as spicy fermented cabbage.

Where Did Kimchi Originate?

Kimchi is a Korean food tradition connected to farming, seasonal foods, preservation, family knowledge, and community life.

Over generations, Korean households developed ways to prepare and preserve vegetables. Recipes changed according to local weather, available ingredients, and family traditions.

Kimjang is the shared practice of making and sharing large amounts of kimchi, often before winter.

In 2013, UNESCO added “Kimjang, making and sharing kimchi in the Republic of Korea” to its Representative List of the Intangible Cultural Heritage of Humanity.

UNESCO explains that kimjang helps people work together, pass knowledge from one generation to the next, and strengthen Korean cultural identity.

Kimchi is now enjoyed around the world, but its global popularity should not separate it from its Korean origin.

From the NUF Kitchen: How Kimchi Changes Over Time

Real NUF kitchen and production photos are paired with editorial ingredient and serving images to show the process from salted napa cabbage to finished kimchi.

At NUF, we see kimchi change as it continues to ferment under refrigeration.

Newly packed cabbage is usually firmer and more vegetable-forward. The garlic, pepper, and other seasonings may taste more separate.

As fermentation continues:

• The sour taste becomes stronger.

• The seasoning blends together.

• The aroma becomes deeper.

• Gas may develop inside the package.

• The vegetables slowly soften.

• The kimchi becomes more useful for cooking.

These are practical observations from our kitchen, not an exact timetable for every batch.

Each batch may develop differently because of the vegetables, salt level, temperature, packaging, and fermentation conditions.

NUF focuses on careful preparation, steady refrigeration, and packing kimchi fresh to order.

Frequently Asked Questions

Is kimchi just fermented cabbage?

No. Kimchi can also be made with radish, cucumber, green onion, mustard greens, and many other vegetables.

Is every kimchi fermented?

Many types are fermented, but fresh kimchi such as geotjeori may be eaten soon after seasoning.

Does all kimchi contain fish sauce?

No. Some recipes contain seafood ingredients, while others use plant-based seasonings.

Is all kimchi red?

No. White kimchi and water kimchi may contain little or no red pepper.

Does kimchi need to be refrigerated?

Fresh commercial kimchi should be stored according to the package directions. Refrigeration helps slow fermentation.

Can kimchi be cooked?

Yes. Aged kimchi is often used in fried rice, stew, noodles, pancakes, and other cooked dishes.

Is sour kimchi spoiled?

Not always. Becoming more sour is a normal part of fermentation.

Why is there empty space in a kimchi jar?

The empty space, called headspace, gives gas and brine room to move during fermentation.

Kimchi Is More Than a Food Trend

Kimchi is not simply spicy cabbage, a condiment, or a modern probiotic product.

It is a broad Korean food tradition built around vegetables, seasoning, fermentation, seasonal ingredients, and shared knowledge.

Its flavor changes over time. A jar may begin crisp and bright, develop a balanced tang, and later become more sour and useful for cooking.

Someone trying kimchi for the first time does not need to begin with complicated health claims.

Start by looking at:

• The main vegetable

• The ingredient list

• The spice level

• The fermentation stage

• How you plan to eat it

Then add a small serving to a meal you already enjoy.

Explore NUF Kimchi

New Universe Food makes naturally fermented kimchi in Northern Florida with a focus on real vegetables, clear ingredients, and traditional flavor.

Our current kimchi selection includes:

• Classic Kimchi

• Vegan Kimchi

• Cubed Radish Kimchi

Made without fish sauce. No added MSG.

Explore NUF Kimchi →

Research and Cultural Sources

This guide was developed using peer-reviewed research on kimchi fermentation, microbial communities, and probiotic terminology, along with UNESCO’s official information about kimjang.

Key sources include:

1. Jung JY, Lee SH, Jeon CO. “Kimchi Microflora: History, Current Status, and Perspectives for Industrial Kimchi Production.” Applied Microbiology and Biotechnology. 2014.

2. Lee M, et al. “Unraveling Microbial Fermentation Features in Kimchi.” 2020.

3. Lee SH, et al. “Source Tracking and Succession of Kimchi Lactic Acid Bacteria During Fermentation.” 2015.

4. Cha IT, et al. “Does Kimchi Deserve the Status of a Probiotic Food?”

5. UNESCO. “Kimjang, Making and Sharing Kimchi in the Republic of Korea.”