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Kimchee Observe

How pickling proceeds: Fermentation is the work of millions of microbes. You can't see them without a microscope, but you can see, smell and taste evidence of their activity.

Each day, press down on the jar or bottle top so that cabbage juice always covers the cabbage, and the cabbage is kept from contact with the air. You are cultivating anaerobes, organisms that grow best where there is no oxygen. As you press down on the cabbage, you will see bubbles of carbon dioxide (CO2) rising to the surface. Where do they come from?

How long does it take?: Cabbage can take 3 days to 2 weeks to complete fermentation, depending on the surrounding temperature. The warmer it is, the faster it ferments. If your classroom is a steady 25 degrees C (75 degrees F) or more, you can have kimchee within 4 days; sauerkraut requires more like 2 weeks.

Measure the acidity of the cabbage juice with pH paper daily. Link toKimchee Explore (pH indicator text) You can record the date and pH directly on the paper strips, and then tape them on the bottle to keep track of changes.

Your kimchee or sauerkraut is ready to eat when the pH of the cabbage juice has dropped from about pH 6.5 to pH 3.5. You'll have to open the sliding seal in order to taste the cabbage. When you remove the top, however, the bottle's contents are exposed to air, which may allow different kinds of microbes to grow. To be safe, refrigerate after opening. Do not eat the kimchee or sauerkraut if mold is present.

Smell and taste your kimchee: Do you notice the aroma of garlic and pepper? How do the odors change with time? Can you taste the garlic and the pepper? You can explore flavors by adding other ingredients such as ginger, radishes, or different amounts of pepper and garlic.

National Science Foundation   Bottle Biology, an instructional materials development program, was funded by a grant from the National Science Foundation administered by the University of Wisconsin-Madison.   Wisconsin Fast Plants