Researchers at the Georgia Institute of Technology in the United States have highlighted a traditional fermentation technique that appears to yield superior kimchi. Their findings point to Onggi, earthen pots with porous walls, as a key factor in achieving a richer, more aromatic finish compared to modern industrial methods. This work was shared publicly through a scientific journal, emphasizing how heritage methods can rival contemporary processes when it comes to flavor development in fermented foods.
In large-scale production, kimchi is typically fermented in glass, steel, or plastic vessels. However, experts argue that such modern containers may not foster the same depth of fermentation as the time-honored Onggi method. The porous nature of Onggi walls seems to create a microenvironment that favors salt-loving lactic acid bacteria, while naturally restraining aerobic bacteria that can introduce off-flavors into the final product. Beyond flavor control, Onggi fermentation has been associated with higher acidity levels and increased antioxidant activity in kimchi, which may contribute to both taste and potential health benefits.
According to the researchers, the team studied gas exchange during kimchi fermentation in both an Onggi and a glass jar. They employed a carbon dioxide sensor to monitor gas release and examined the physical structure of the Onggi, paying particular attention to wall porosity. The observations suggest that the porous walls play a crucial role in directing the fermentation process, helping to create a stable environment for the beneficial microbes involved in kimchi maturation.
The analysis revealed that when kimchi is fermented in Onggi, brine can migrate through the wall and evaporate on the outer surface, leading to the formation of visible salt crystals. This phenomenon did not occur with glass containers, where the exchange between brine and air is more static. The dynamic exchange within Onggi appears to support ongoing salt balance and microbial activity, contributing to a distinctive texture and flavor profile observed in traditionally produced kimchi.
Further measurements showed that Onggi-enabled fermentation involves the continuous inhalation and release of carbon dioxide as the microbial ecosystem thrives. This natural breathing process helps maintain a lower internal gas pressure, which is believed to support steadier fermentation and potentially shorten the risk of excessive gas buildup. The outcome is a kimchi with a more nuanced acidity, brighter aroma, and a finish that many tasters describe as more balanced and authentic to regional styles. In contrast, the more closed environment of glass vessels tends to yield a different pace and character of fermentation, underscoring how vessel design can steer microbial dynamics and final taste.