We get asked “What is Kimchi?”, a lot.
Kimchi is a healthy & delicious traditional Korean staple that accompanies every meal (even non-Korean dishes). It is a naturally fermented pickle made from:
variety of produce (napa cabbage, radish, mustard greens, beets, etc)
aromatics (onions, garlic, green onions, ginger)
seasoning (red chili pepper flakes, fish sauce, salted shrimps).
By fermenting kimchi, it creates the effervescent quality that kimchi is well-known for, accompanied by its distinct tangy, sour, spicy and savory flavors.
Like many other cultures, Koreans used fermentation as a method of preserving food prior to refrigeration, to sustain and nourish during periods of lack. Traditionally, the community came together after the late harvest to preserve its yield; this collective activity is called kimjang, a time of making and sharing kimchi. Family members, relatives and neighbors, regardless of age, all contributed to making large volumes of kimchi that would sustain families throughout the harsh winter when fresh vegetation was non-existent.
The finished kimchi was stored in large earthenware containers and buried underground, where the temperature-regulated environment protected its contents from freezing.
Fermentation is an ancient method, but today we are seeing its revival. Many look to kimchi for its health benefits, others simply for its flavors. But how kimchi is made, has not changed much.
Kimchi is a lacto-ferment. It starts naturally with the raw materials that already contain numerous micro-organisms, and of these micro-organisms, it is the lactic acid bacteria (LAB) that is responsible for the fermentation. LABs convert carbohydrate (sugar, starches) to lactic acid, which is the dominant byproduct, followed by carbon dioxide and organic acids.
To create a supportive environment for LABs to proliferate, we start with a brine. Brining the main vegetable is a crucial step in the initial stage of fermentation. Salt helps prevent spoilage by suppressing the bad bacteria, which is intolerant to salt, while simultaneously encouraging the growth of the beneficial bacteria (LAB).
Salt also helps draw out the excess water from the vegetable, breaks down the cellular walls and penetrates the vegetable, thereby seasoning it. The result is a firm, pliable, crunchy texture. (This helps when applying additional seasoning to better adhere to the vegetable).
Further, LABs require an anaerobic environment to thrive, which is why when we make kimchi we try to minimize the oxygen in the container by packing down the vegetables, this helps minimize air gaps between the contents. The other important thing to do, when packing and fermenting, is to keep the contents submerged under the liquid line to prevent contact with the oxygen above the surface to prevent surface mold. As fermentation kicks in, carbon dioxide is produced replacing the remainder of the oxygen, reinforcing the anaerobic habitat.
The group of LAB microorganisms involved in fermentation is diverse and each LAB has its function and characteristics that shine at different stages of fermentation under a range of conditions. The essential goal for LAB is to produce acid, each producing different amounts and types that allow subsequent LABs to come, play, and fulfill their tasks. Over time, as the acidity increases and the pH levels drop, it creates an inhospitable environment for harmful micro-organisms to survive. For humans consuming the ferment, well, things are considerably more favorable.
Signs of fermentation:
tiny bubbles in the liquid
vegetables pushing up from the gas buildup
At this point, you can move the kimchi into the fridge. Make sure to press down on the kimchi to keep it below the liquid line, tighten the lid and place it in cold storage. It will continue to ferment in the cold environment but at a slower pace, deepening the flavors; the slower the pace, the better the quality of the kimchi.
Salt and temperature affect fermentation significantly: Less salt and/or warmer temperatures speeds up the fermentation.
To ensure the quality and safety of your kimchi, you want to ensure that you have a minimum salinity of 2% to prevent mold.
To maintain a crispier firm texture, you want to avoid fermenting in high temperatures which can turn your kimchi mushy; ideal ambient temperature range to kick start the fermentation is between 65-72°F.
Other factors that affect fermentation:
denseness of vegetable: beets vs. bok choy - less dense produce ferments faster
water content: napa cabbage vs. cucumbers - the higher the water content, the faster it ferments
size of cut: whole radish vs. cubes - the smaller the size, the faster it ferments
We encourage you to use on-hand produce, eat seasonal and experiment. Find that sweet spot of fermentation that you enjoy as you curate your own kimchi. Use up your fresh odds & ends and help prevent food waste in the home, keep more money in your pocket, while promoting health through a traditional practice that foster real food & eating.
Enjoy and keep us posted! We love hearing from our community of yummy creators spreading the love of kimchi.