Kimchee: Korean Delight
Fermentation Experiments with Bottle Biology

Introduction:

Pickling is one of the most ancient forms of preserving food. You will be using microbes to convert sugars into lactic acid. The microbe involved is called lactobacilli. As the population of lactobacilli grows, they eat the natural sugars in plant juices and produce lactic acid as a waste product. As the lactic acid levels increase, so does the acidity. This highly acidic environment prevents the growth of other bacteria that would under normal conditions feast on the food causing spoilage. In this lab, you will be making kimchee and studying lactic acid fermentation.

Materials:

Chinese cabbage (cut into 5 to 7 inch chunks)
1 red hot chili pepper, chopped
2 cloves garlic, thinly sliced
3 teaspoons non-iodized (pickling) salt
one 2 liter soda bottle
large plastic lid (petri plate lid)
pH indicator paper
small plastic pipette

Procedure

  1. Cut the bottle top off from base, 10 to 15 cm from the top.
  2. Alternate layers of cabbage, garlic, pepper and sprinkling of salt in the soda bottle. Press each layer down firmly until the bottle is packed full.
  3. Place the lid, rim side up, on top of ingredients and press down again.
  4. Press down occasionally for the next few hours. When there is space, fit the bottle top inside the bottle bottom, forming a sliding seal. Air should bubble out around the edge of the petri plate when you press down on the lid. Press daily on the sliding seal to keep the cabbage covered by a layer of juice at all times.
  5. Measure and record the acidity of the fresh juice on top each day with a pH indicator paper.
  6. When the pH drops to 3.5, your kimchee will be ready (about 3 to 7 days). Enjoy!!

Cautions:

Reference:

1990 Fast Plants and Bottle Projects, Department of Plant Pathology, University of Wisconsin, 1630 Linden Dr., Madison, WI 53706

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