Introduction: Science of Kimchi

About: I am an 18-year-old student in 12th grade, I enjoy baking, running, programming, 3-D design, photography, and nature!

Kimchi is one of the worlds healthiest probiotics, it is packed with vitamins and health microorganisms and it can be made right at home. In this Instructable, I will show you how to make easy, yummy and healthy kimchi, as well as talk about the complex science that makes it so beneficial and delectable!

Step 1: Ingredients and Equipment


  • 1 large head of Napa Cabbage
  • 1 cup Daikon Radish
  • 4 Green Onions
  • 1/4 Cup Sea Salt (non-iodized, I use Celtic sea salt)
  • 1-3 tablespoons Korean Chili Pepper; Gochugaru (3 tablespoons will be very spicy so I recommend starting with just one)
  • 1 tablespoon grated Garlic
  • 1 teaspoon grated Ginger
  • 1 teaspoon Sugar
  • Water (Try to use distilled or reverse osmosis water, water with fluoride or chlorine will prevent fermentation)

You can also add other veggies such as bok-choy, carrots, etc.


  • Cutting board and a Chef's Knife
  • Large mixing bowl
  • Small mixing bowl
  • Basic measuring utensils
  • Colander
  • Plate and a weight for soaking cabbage
  • Jar with a seal-able lid
  • Gloves - Optional to protect your hands when mixing

Step 2: Prepping the Cabbage

In order to make kimchi, the Napa cabbage must be soft and tender. The first step is to cut the cabbage, first into four quarters lengthwise and then into 1-2 inch strips crosswise, like pictured. Then place all the cabbage into the large mixing bowl and add the salt. Using gloves (if you want) mix the non-iodized salt into the cabbage until well mixed. Finally, add enough water to cover the top of the cabbage, then use the plate to cover the cabbage. You will want to add a weight to the plate and remove excess water as the cabbage sets, let sit for at least 1 hour.

Step 3: Combining the Spices

Once the cabbage is almost done soaking you can make your spice mixture. First, finely mince or grate the ginger and garlic, and add them to a small mixing bowl. Then pour in the Gochugaru and sugar and mix it. Finally, mix in the first two tablespoons of water, continue to add more until it forms a smooth, but not watery paste.

Step 4: Mixing Everything Together!

The next step is to mix everything together, but first, you need prep the other vegetables starting with the Daikon radish. Cut the radish into 2 inch long matchsticks until it fills at least one cup. Then cut the green onions into inch long pieces. Rinse and strain the cabbage in the colander, then add it back to the large mixing bowl without any water. Mix in the daikon radish and the green onions. Finally, add the seasoning paste and mix everything very well until all the cabbage is well coated.

Step 5: Fermentation and Refrigeration

The final step in the process is fermentation, which is what gives Kimchi its unique flavor. Once you have mixed everything, get a clean jar with a sealable lid. Pack the mixture into the jar leaving just under an inch at the top. It is very important to pack the kimchi down so the brine submerges all the vegetables. If the veggies are not fully submerged there is a chance mold could form. Also to have the best fermentation, make sure all air bubbles are removed. If you see an air bubble use your finger or a skewer to help the air escape.

Once all of this has been completed put the lid(s) on the jar(s). Let the kimchi sit at about 65°F for 1-5 days to ferment checking each day to pack the cabbage down, check for air bubbles, and tasting to see if it is fermented to your liking. If you are happy with it place it in the fridge for storage. You can enjoy it right away, or give it a weak for the best flavor!

Step 6: Conclusion - the Science

Kimchi, like yogurt and kombucha, is a very healthy probiotic, which is very good for digestion and kills bad bacteria. However, eating napa cabbage alone wouldn't do this, kimchi is so healthy because of the fermentation. It starts with the salt and cabbage which are the most important part of the process, by salting the cabbage it causes osmosis, which causes the cell structure to weaken which softens the cabbage. The cabbage once rinsed is mixed with all the other ingredients which are mostly just for flavor. Then the microorganisms take over, the most important is Lactobacillus Plantarum which helps give kimchi its unique flavor. Lactobacillus Plantarum from the salted cabbage which also causes most of the fermentation. Lactobacillus Plantarum thrives in warm, low oxygen environments which is why kimchi must me surrounded in brine in a sealed container and kept at about 65°F. Then, sugars begin to break down and metabolize creating lactic acid, decreasing pH. Kimchi in an ideal situation should have a pH around 4.5.

Kimchi, like all fermented foods, has a lot of science behind it. Changing any variable, the temperature, the time, the ingredients, can have a major impact on the outcome of the end product. So, if you decide to make kimchi, consider yourself a chef, but also a scientist.

If you wish to learn more here are a few resources I found that are reliable sources for more on the science and facts:

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