What should I do if my kimchi stops bubbling after a day or two — has fermentation finished or stalled?

Question

What should you do if your kimchi stops bubbling? Learn how to tell if your fermentation has finished successfully or if it has stalled prematurely.

Answer 1

If your kimchi stops bubbling after only a day or two, it likely hasn't finished fermenting; fermentation has probably slowed down due to temperature fluctuations or insufficient salt. Monitor the taste and smell, and consider adjusting the temperature or adding a small amount of salt solution.

Detailed Explanation:

Kimchi fermentation is a complex process driven by lactic acid bacteria (LAB). These bacteria consume sugars in the vegetables and produce lactic acid, carbon dioxide (the bubbles you see), and other flavorful compounds. The bubbling is a visual indicator of active fermentation.

Here's a breakdown of why bubbling might stop prematurely and what to do:

1. Temperature: LAB are sensitive to temperature. Ideally, kimchi should ferment at a consistent temperature between 64°F and 72°F (18°C and 22°C). If the temperature drops significantly, the bacteria become less active, slowing or stopping fermentation. Move your kimchi to a warmer (but not hot) location.
2. Salt Concentration: Salt is crucial for controlling the growth of undesirable bacteria and creating a favorable environment for LAB. If the salt concentration is too low, other microorganisms might outcompete the LAB, leading to off-flavors or spoilage. If you suspect low salt, dissolve 1 teaspoon of salt in 1/2 cup of water and add it to the kimchi.
3. Sugar Depletion: While less common in the early stages, the bacteria might have consumed most of the available sugars. This is more likely if you used vegetables with lower sugar content. However, this is less likely after only a day or two.
4. Check for Mold or Off-Odors: If the kimchi smells rotten, moldy, or otherwise unpleasant, it may have spoiled. Discard it. A sour, tangy smell is normal and desirable.
5. Taste Test: The best way to determine if fermentation is progressing is to taste the kimchi. It should become increasingly sour and tangy over time. If it still tastes very bland after a few days, fermentation may have stalled.

Continue to monitor the kimchi for several days, tasting it regularly. If the bubbling doesn't resume, but the taste is developing nicely, it's likely that fermentation is simply proceeding at a slower pace.

Pro Tip:

Always use clean utensils when handling your kimchi during fermentation to avoid introducing unwanted bacteria or mold. Press down on the kimchi daily to ensure it remains submerged in its own brine, which helps prevent mold growth.