Science has proven that traditional clay jars (onggi) are the best tool for fermenting kimchi.
A traditional staple of Korean cuisine, kimchi is a fermented spicy cabbage that has become a must-have for health-conscious foodies around the world. However, when comparing the many ways of preparing kimchi, science has proven onggi-produced kimchi is the most efficient.
Published in the Journal of the Royal Society Interface, Ph.D. student Soohwan Kim and Georgia Tech professor David L. Hu found that the porous structure of onggi is similar to that of loose soil, where lactic acid bacteria, which is necessary for the fermentation process, are found.
These micro-pores, which are absent in glassware, allow for the exhalation of carbon dioxide, which aids the fermentation’s signature process and creates an ideal environment for lactic acid bacteria.
Glassware often prevents the gradual release of carbon dioxide, resulting in the gas “suffocating” the beneficial lactic acid bacteria.
The consistent outflow of carbon dioxide also creates a “positive pressure” within the onggi, preventing external contamination from entering its walls.
More from NextShark: Awkwafina nomination for NAACP Image Award sparks renewed backlash
The study answers questions regarding the secret to onggi kimchi’s beneficial qualities of greater acidity, higher amounts of lactic acid bacteria and quick fermentation process.
“We wanted to find the ‘secret sauce’ for how onggi make kimchi taste so good,” Hu explained in the experimental study. “So, we measured how the gases evolved while kimchi fermented inside the onggi – something no one had done before.”
To find the “secret sauce,” Kim traveled to his hometown in South Korea’s Jeju-do island, where onggi continue to be crafted. Purchasing a jar, the mechanical engineer Ph.D. student brought it home to carry out the experiment.
More from NextShark: Comedian Uncle Roger Rates Gordon Ramsay’s Indonesian Egg Fried Rice
Kim shared his amazement at the capabilities of onggi in a statement.
Onggi were designed without modern knowledge of chemistry, microbiology, or fluid mechanics, but they work remarkably well. It’s very interesting to get new insights into ancient technology through the lens of fluid dynamics [...] It’s amazing that, for thousands of years, people have been building these special containers out of dirt, but in many ways, they are very high tech.
The two researchers stated that their goal for the study was to “draw attention to this traditional artisan work and inspire energy-efficient methods for fermenting and storing foods.”