Why does kimchi produce gas and bubbles during fermentation? What does that indicate?

Question

Why does kimchi produce gas and bubbles? Find out what this activity indicates about the health of your ferment and the work of the good bacteria.

Answer 1

Kimchi produces gas and bubbles during fermentation because of the activity of beneficial bacteria, primarily *Leuconostoc* species, which produce carbon dioxide as a byproduct of consuming sugars in the vegetables. This gas production is a normal and desirable sign of healthy fermentation.

Detailed Explanation:

Kimchi fermentation is a complex process driven by various microorganisms, primarily lactic acid bacteria (LAB). These bacteria thrive in the anaerobic (oxygen-deprived) environment created during kimchi preparation. The most prominent gas production comes from *Leuconostoc* bacteria. These bacteria consume the sugars present in the vegetables, such as cabbage, radish, and garlic, and convert them into lactic acid, carbon dioxide (CO2), and other metabolic byproducts. The CO2 is what you see as bubbles.

The presence of gas and bubbles indicates that the fermentation process is actively underway and that the beneficial bacteria are multiplying and producing the desired acids that give kimchi its characteristic sour and tangy flavor. As fermentation progresses, other types of LAB, such as *Lactobacillus*, become more dominant and continue to contribute to the flavor profile, although they typically produce less gas than *Leuconostoc*. The amount of gas produced can vary depending on factors such as temperature, salt concentration, and the specific ingredients used.

Pro Tip:

If your kimchi container is bulging excessively due to gas buildup, gently 'burp' it by opening the lid slightly to release the pressure. This prevents the container from exploding and ensures a safer fermentation process.