Kimchi brine can last for several months when stored properly in the refrigerator. The high salt content in the brine acts as a natural preservative, helping to extend its shelf life. However, its quality might gradually decline over time.
As long as the kimchi brine is kept in a sealed container or jar and stored in the refrigerator at a consistent temperature, it should remain safe to consume for at least 6 months, and some sources suggest it can last up to a year. It's essential to ensure the container is tightly sealed to prevent contamination and to maintain the brine's freshness.
Keep in mind that over time, the brine's flavor may change, becoming stronger and more acidic. If you notice any off-odors, mold growth, or other signs of spoilage, it's best to discard the brine. Additionally, if the kimchi brine becomes too salty or acidic for your taste, you can dilute it with water to adjust the flavor.