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Kimchi: A Delicious Korean Probiotic and How to Prepare it Cheaply at Home

A detailed look at one of the world's most delicious probiotics. And how to make it from scratch.

Kimchi: A Delicious Korean Probiotic and How to Prepare it Cheaply at Home

Kimchi is a traditional Korean fermented vegetable dish, primarily made from nappa cabbage, spices, and other ingredients. It is rich in probiotics, which are beneficial for gut health and overall well-being. This paper will discuss the theory behind kimchi fermentation, focusing on the crucial role of salt, and provide a detailed recipe for making a mildly spiced kimchi at home without using starter cultures.

Theory: The Role of Salt in Kimchi Fermentation

One of the critical factors in making kimchi is the use of salt. Salt plays a vital role in creating an environment that is conducive to the growth of beneficial bacteria (lactic acid bacteria) while inhibiting the growth of harmful or foul-smelling bacteria. The salt concentration is crucial in determining the success of the fermentation process and the final taste and texture of the kimchi.

During the initial stages of kimchi preparation, the nappa cabbage is soaked in a brine solution with a specific salinity, usually between 2% and 5%. This salinity level creates an environment where beneficial bacteria can thrive while suppressing the growth of pathogenic and spoilage-causing bacteria.

Probiotic bacteria are naturally present on the surfaces of vegetables, utensils, and even human skin. These beneficial bacteria initiate the fermentation process when the conditions are favorable, which is achieved by using the right amount of salt.

Fermentation Process: Bacteria, Acid Production, Yeasts, and Gas

During fermentation, lactic acid bacteria multiply and convert the sugars in the cabbage and other vegetables into lactic acid. This acidification of the mixture creates an environment that is highly unfavorable for the growth of pathogens and spoilage-causing microorganisms, ensuring the safety and preservation of the kimchi.

Yeasts also play a role in kimchi fermentation, contributing to the complex flavor profile of the final product. However, their role is secondary to that of lactic acid bacteria.

As the fermentation process progresses, gases such as carbon dioxide are produced, which can cause the mixture to bubble and release a distinct odor. This odor is a natural byproduct of the fermentation process and is not a cause for concern. It is essential to allow for gas release during fermentation, either by using an airlock system or by periodically opening the container to release pressure.


Recipe: Mildly Spiced Kimchi


  • 2 pounds (about 1 kg) nappa cabbage

  • 1/4 cup (60g) sea salt or kosher salt (non-iodized)

  • 1 cup (240ml) water

  • 4 cloves garlic, minced

  • 1-inch (2.5cm) piece of ginger, grated

  • 1 small onion, minced

  • 2 tablespoons (30g) Korean red pepper flakes (gochugaru), or to taste

  • 1 tablespoon (15g) fish sauce or soy sauce (optional)

  • 1 teaspoon (5g) sugar

  • 4 green onions, chopped into 1-inch (2.5cm) pieces

  • 1 small daikon radish, julienned


  1. Prepare the cabbage: Remove any damaged outer leaves and cut the cabbage into quarters, lengthwise. Rinse the quarters under cold water, then chop them into bite-sized pieces.

  2. Salt the cabbage: In a large bowl, combine the cabbage pieces and salt. Massage the salt into the cabbage using your hands, then add the water. Let the cabbage sit in the brine for at least 2 hours, or until the cabbage is wilted and softened.

  3. Rinse and drain the cabbage: After the cabbage has wilted, rinse it thoroughlyunder cold water to remove excess salt. Drain the cabbage well, using your hands or a colander to squeeze out as much water as possible. Set aside.

  4. Prepare the spice paste: In a separate bowl, combine the minced garlic, grated ginger, minced onion, Korean red pepper flakes, fish sauce (or soy sauce), and sugar. Mix well to form a thick paste.

  5. Combine the cabbage and spice paste: Add the spice paste to the drained cabbage, along with the chopped green onions and julienned daikon radish. Mix well, ensuring that the cabbage is evenly coated with the spice paste. You may use gloves to protect your hands from the chili pepper.

  6. Pack the kimchi into a fermentation container: Transfer the kimchi mixture into a clean, sterilized glass jar or a fermentation crock, pressing down firmly to remove any air pockets. Ensure that there is at least an inch (2.5 cm) of headspace at the top of the container to allow for gas expansion during fermentation.

  7. Ferment the kimchi: Cover the container with a tight-fitting lid, an airlock system, or a clean cloth secured with a rubber band. Store the kimchi in a cool, dark place, away from direct sunlight, at room temperature (around 68°F or 20°C) for 1 to 5 days. Check the kimchi daily, releasing any gas buildup if necessary, and tasting it to determine when it has reached your desired level of fermentation.

  8. Refrigerate the kimchi: Once the kimchi has achieved the desired level of fermentation, transfer it to the refrigerator to slow down the fermentation process. The kimchi can be consumed immediately, but its flavor will continue to develop and improve over time. Properly fermented and stored kimchi can last for several months in the refrigerator.

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