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Want Better Kimchi? Make It Like the Ancients Did:
Fermented foods like kimchi have been an integral part of Korean cuisine for thousands of years. Since ancient times, Korean chefs have used onggi — traditional handmade clay jars — to ferment kimchi. Today, most kimchi is made through mass fermentation in glass, steel, or plastic containers, but it has long been claimed that the highest quality kimchi is fermented in onggi.
Kimchi purists now have scientific validation, thanks to recent research from David Hu, professor in the George W. Woodruff School of Mechanical Engineering and the School of Biological Sciences at Georgia Tech, and Soohwan Kim, a second-year Ph.D. student in Hu's lab.
In a combined experimental and theoretical study, Hu and Kim measured carbon dioxide levels in onggi during kimchi fermentation and developed a mathematical model to show how the gas was generated and moved through the onggi's porous walls. By bringing the study of fluid mechanics to bear on an ancient technology, their research highlights the work of artisans and provides the missing link for how the traditional earthenware allows for high quality kimchi.
[...] "We wanted to find the 'secret sauce' for how onggi make kimchi taste so good," Hu said. "So, we measured how the gases evolved while kimchi fermented inside the onggi — something no one had done before."
The porous structure of these earthenware vessels mimics the loose soil where lactic acid bacteria — known for their healthy probiotic nature — are found. While previous studies have shown that kimchi fermented in onggi has more lactic acid bacteria, no one knew exactly how the phenomenon is connected to the unique material properties of the container.
[...] They concluded that the onggi's porous walls permitted the carbon dioxide to escape the container, which accelerated the speed of fermentation. The onggi's porosity also functioned as a "safety valve," resulting in a slower increase in carbon dioxide levels than the glass jar while blocking the entry of external particles. Their data revealed that the carbon dioxide level in onggi was less than half of that in glass containers.
They also found that the beneficial bacteria in the onggi-made kimchi proliferated 26% more than in the glass counterpart. In the glass jar, the lactic acid bacteria became suffocated by their own carbon dioxide in the closed glass container. It turns out that, because the onggi releases carbon dioxide in small rates, the lactic acid bacteria are happier and reproduce more.
[...] "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," Hu said. "We discovered that the right amount of porosity enables kimchi to ferment faster, and these onggi provide that."
Kim said that some artisans still use ancient methods when making onggi, but their numbers are decreasing. Now, the market is flooded with inauthentic versions of the vessels.
"We hope this study draws attention to this traditional artisan work and inspires energy-efficient methods for fermenting and storing foods," he said. "Also, the onggi are quite beautiful."
Journal Reference:
Kim Soohwan and Hu David L. 2023 Onggi's permeability to carbon dioxide accelerates kimchi fermentation J. R. Soc. Interface 20 http://doi.org/10.1098/rsif.2023.0034
(Score: 3, Informative) by takyon on Tuesday May 02, @03:05AM (11 children)
1. Make it, put it in glass quart jars
2. Compress it down as best as you can
3. Don't overfill the jar, or put it on something that can handle leakage
4. Keep it out for a few days, then transfer to the fridge for long-term use
But I'm already far from creating authentic kimchi since I use regular green cabbage (Brassica oleracea var. capitata).
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(Score: 2) by driverless on Tuesday May 02, @05:55AM (10 children)
Given that kimchi is half-rotted cabbage (and some other ingredients), I think the best way to make it is not at all. Not being disparaging here, it's just a very acquired taste. Kid I went to school with would occasionally bring it for lunch, and when he uncapped his lunch box everyone would move some distance away from him.
So seeing something saying that prep via method A is better than method B feels like reading a comparison of the best way to prepare surströmming, another notorious fermented food.
(Score: 5, Informative) by takyon on Tuesday May 02, @06:44AM (3 children)
It's not "half-rotted". It's preserved by lactic acid fermentation and refrigeration, similar to sauerkraut. The anaerobic, acidic environment kills many unwanted microbes and prevents decomposition (rotting).
The smell can be strong, but it's easy to get used to and you can adjust it if you make it yourself by using less chili, garlic, ginger, etc. I have to do that because nobody but me would eat it otherwise (due to the spiciness).
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(Score: 3, Insightful) by driverless on Tuesday May 02, @07:35AM (2 children)
I think the issue is that to western palates there's quite a difference between fermented as in cheese and fermented as in kimchi or, for non-Germans, sauerkraut. That's what I meant by "rotten", something like cheese is acceptably fermented while kimchi is seen as waaaay too fermented.
(Score: 4, Informative) by DeathMonkey on Tuesday May 02, @03:52PM (1 child)
Shelf stable pickles are fermented as well and Americans seem to handle them fine.
(Score: 0) by Anonymous Coward on Wednesday May 03, @12:57AM
Aren't most pickles on the shelf not fermented, but just brine infused?
(Score: 4, Interesting) by pTamok on Tuesday May 02, @07:24AM (2 children)
Lots of foods are an acquired taste, disgusting to some:
Cheese is 'rotten milk', especially blue cheese. Yoghurt is also fermented, and there are many other fermented milk products,
Beer is rotten wort (boiled-up sprouted barley). Adding hops as a flavouring/preservative is relatively recent.
Well-hung game acquires its flavour by partially rotting the meat. A joke was to say that the grouse were ready to eat when the body dropped off the head (they were/are hung up to mature by the head)
Raakfisk and Gravad Laks are rotted fish (trout and salmon respectively). Rotted shark (Hákarl) is an Icelandic delicacy.
Sauerkraut is fermented cabbage without the chilli.
Salami is a sausage made with fermented meat
For a more comprehensive list:
https://en.wikipedia.org/wiki/List_of_fermented_foods [wikipedia.org]
It includes things like bread, where the gas to raise the bread is generated by yeast using sugar from the dough
So fermented food is not always awful. Drink a pint of beer while eating a cheese roll with some (brined) pickles. Everything except the butter is a product of fermentation.
(Score: 2) by RamiK on Tuesday May 02, @12:09PM (1 child)
Bread raises by fermentation and is universally liked.
compiling...
(Score: 0) by Anonymous Coward on Tuesday May 02, @03:40PM
Don't forget the aged beef too...
Cheers to half rotted food! 🍕 🍻
(Score: 2) by richtopia on Tuesday May 02, @02:40PM (1 child)
Agree. Samsung was my customer for a while and they always had it in the cafeteria, and once was enough for me. I'm okay with being an uncultured savage!
To the post's title:
Want Better Kimchi?
No.
(Score: 3, Interesting) by driverless on Tuesday May 02, @02:50PM
Well, not unless it's Satan's kimchi [science.org].
(Score: 0) by Anonymous Coward on Tuesday May 02, @03:35PM