I fell down a youtube rabbit hole of people making homemade kimchi, but I was surprised to find none of the ingredients or techniques I associate with fermented foods / fermentation in general. At first I thought it was the salt added to the cabbage that made a brine, but I realized it was to reduce the water content of the cabbage, with the salt washed away thoroughly. Then I assumed it was fermented like sauerkraut, until I found out those are two different species of cabbage. I also noticed there wasn’t any added microbes or enzymes like when making wine or cheese, so what causes the reaction?
In: Biology
> two different species of cabbage
How would this affect what type of bacteria/microbe ferments the vegetable?
At every moment, we are surrounded by a huge number of bacteria. Some of that bacteria (such as [levilactobacillus brevis](https://en.wikipedia.org/wiki/Lactobacillus_brevis)) will cause vegetables to ferment if it’s the main bacteria left. And wouldn’t you know it, this specific bacteria is mentioned as a microbe of both sauerkraut and kimchi.
Edit: the wiki page has a section about [kimchi microorganisms](https://en.wikipedia.org/wiki/Kimchi#Microorganisms_in_kimchi) that lists out all of the common ones, while the sauerkraut wiki is listed on a [separate list](https://en.wikipedia.org/wiki/Lactic_acid_fermentation#Applications). The main commonality is that certain ‘everywhere bacteria’s grow in brine better (which starts the fermentation and increases acidity) and eventually acidic brine better (which keeps the fermentation going).
Fermentation is the result of microorganisms, generally some kind of lactic-acid producing bacteria in the case of vegetables like cabbage. Multiple species interact, but the ones that produce the tangy flavor and preservative action are Lactobacillus Kimchii, named for an obvious reason. Yogurt, sauerkraut, fermented pickles, miso… all rely on this process.
You don’t need to add the microbes, they’re all around us and on the foods we eat already, you just need to create an environment in which they thrive and others struggle. Adding salt kills things like yeasts and molds, and helps the “good” microbes take hold and thrive. Once they do they convert sugars to lactic acid, which lowers the pH of the food and makes it impossible for other microbes to thrive.
By contrast in the case of wine it’s the opposite, you do your best to inhibit the growth of bacteria, while allowing the natural yeasts on the grape skins (or added yeasts) to take hold and ferment sugars into alcohol.
due to bacteria on the veggies. salt helps by killing bad microbes, letting good bacteria grow. these bacteria produce acid, which makes kimchi tangy and preserves it.
The bacterias (or fungi) are already present. For most of history, people did not know about the causes of fermentation and it was just something that happened with the environment. It is part of the “terroir”.
You will get fermentation if you put leaves or peels in water with sugar. That is how some starters are made.
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