The best kimchi is made in earthenware pots. Science reveals why.
The best kimchi is made in earthenware pots. Science reveals why.
by washingtonpost
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washingtonpost
**From reporter Carolyn Y. Johnson:**
*Experiments show that the traditional onggi pots “breathe” carbon dioxide to create ideal conditions for probiotic microbes to thrive*
For more than a thousand years, the spicy, pungent Korean cabbage dish known as kimchi was fermented in earthenware vessels called “onggi.” Now, a pair of mechanical engineers have unraveled why these ancient Tupperware, made of mud slapped and pressed by hand and spun on a pottery wheel, are exquisitely suited to fostering the growth of probiotic microbes that transform humble cabbage into a culinary superstar.
Kimchi has come into vogue as a superfood, due in part to the gut-healthy bacteria that help deliver its distinctive punch and sour taste. But onggi have not followed suit, perhaps because they are bulky, heavy and fragile, and are not really designed to be portable or fit onto modern kitchen countertops. Instead of using onggi that are buried in the ground, many Koreans fill a second, specialized refrigerator with modern glass, steel or plastic containers of kimchi.
Previous studies had shown that kimchi made in onggi has greater acidity and antioxidant activity, higher numbers of lactic acid bacteria and slower growth of bad-tasting bacteria. But why?
“I thought there’s still a big missing link,” said David Hu, a mechanical engineer at Georgia Institute of Technology who previously unpacked the “wok tossing kinematics” behind making fried rice. “Everyone believed pores are important. Kimchi grown in these conditions have more [lactic acid] bacteria, and people didn’t understand why.”
The new study, published in the Journal of the Royal Society Interface, reveals that the walls of onggi are stippled with tiny micro-pores. Salty water can seep through and evaporate, leaving “salt flowers” on the outside of the vessel. The pores also allow the pottery to exhale some of the carbon dioxide produced by fermentation, creating an ideal environment for lactic acid bacteria to flourish.
The scientists whipped up a standardized and de-spiced version of salted cabbage for experiments that allowed them to make measurements of carbon dioxide, oxygen and pressure within the onggi, to understand how it breathed. They found that even without specialized valves, sensors or monitors, the vessel generated an environment that was conducive to the growth of probiotic bacteria.
1 Comment
**From reporter Carolyn Y. Johnson:**
*Experiments show that the traditional onggi pots “breathe” carbon dioxide to create ideal conditions for probiotic microbes to thrive*
For more than a thousand years, the spicy, pungent Korean cabbage dish known as kimchi was fermented in earthenware vessels called “onggi.” Now, a pair of mechanical engineers have unraveled why these ancient Tupperware, made of mud slapped and pressed by hand and spun on a pottery wheel, are exquisitely suited to fostering the growth of probiotic microbes that transform humble cabbage into a culinary superstar.
Kimchi has come into vogue as a superfood, due in part to the gut-healthy bacteria that help deliver its distinctive punch and sour taste. But onggi have not followed suit, perhaps because they are bulky, heavy and fragile, and are not really designed to be portable or fit onto modern kitchen countertops. Instead of using onggi that are buried in the ground, many Koreans fill a second, specialized refrigerator with modern glass, steel or plastic containers of kimchi.
Previous studies had shown that kimchi made in onggi has greater acidity and antioxidant activity, higher numbers of lactic acid bacteria and slower growth of bad-tasting bacteria. But why?
“I thought there’s still a big missing link,” said David Hu, a mechanical engineer at Georgia Institute of Technology who previously unpacked the “wok tossing kinematics” behind making fried rice. “Everyone believed pores are important. Kimchi grown in these conditions have more [lactic acid] bacteria, and people didn’t understand why.”
The new study, published in the Journal of the Royal Society Interface, reveals that the walls of onggi are stippled with tiny micro-pores. Salty water can seep through and evaporate, leaving “salt flowers” on the outside of the vessel. The pores also allow the pottery to exhale some of the carbon dioxide produced by fermentation, creating an ideal environment for lactic acid bacteria to flourish.
The scientists whipped up a standardized and de-spiced version of salted cabbage for experiments that allowed them to make measurements of carbon dioxide, oxygen and pressure within the onggi, to understand how it breathed. They found that even without specialized valves, sensors or monitors, the vessel generated an environment that was conducive to the growth of probiotic bacteria.
**Read more about this study here, and skip the paywall with email registration:** [**https://www.washingtonpost.com/science/2023/04/07/kimchi-onggi/?utm_campaign=wp_main&utm_medium=social&utm_source=reddit.com**](https://www.washingtonpost.com/science/2023/04/07/kimchi-onggi/?utm_campaign=wp_main&utm_medium=social&utm_source=reddit.com)