The ingredients in a great dish are important to the overall quality of a finished product, but equally important are the preparation methods. Farm fresh eggs will feel like rubber and smell like sulfur if you boil them for twenty minutes- no matter if you just made the most perfect Hollandaise sauce ever. Pie pastry needs to rest before rolling- even if you hand-milled the flour yourself from an heirloom variety of wheat grown using sustainable and organic practices.
Good food takes time!
With this knowledge, it was hard to contain my excitement and curiosity when I decided to attempt the preparation of kimchi, a Korean fermented vegetable sidedish/condiment. Two weeks minimum before it begins to taste "good"? No fancy equipment required? Full of bacteria, flavour and pro-biotics? More fermentation preservation? Sounds delicious to me. I'm sure it will be worth the wait, I told myself.
Now, is it ready yet?
What is Kimchi?
Kimchi has a unique sweet, sour, salty, zingy, bright taste and is usually served cold.
(Kimchi is similar to sauerkraut, however kimchi is less acidic (optimally 0.6-0.8% and 4-5-4.2 pH- kimchi, 1.6-2.0% and 3.7-3.5 pH, sauerkraut). Also, sauerkraut fermentation is completed after 20 days at 23°C with 2.25 % salt content, whereas kimchi fermentation is completed in only 3 days under similar conditions.)
Fermentation, Yeasts, and Lactic Acid Bacteria Warning! It's Wordy!
"The important factors that affect kimchi fermentation are microorganisms, temperature, salt concentration, fermentable carbohydrates, other available nutrients, or any inhibitory compounds in raw materials used, as well as oxygen and pH." ~From the Korean Institute of Science and Technology Information
Salts: Salting reduces the moisture content of the vegetables, helps control fermentation and is a key step in the maintenance of kimchi quality. Optimal salt concentration is 2-3%. If salt concentration is below the optimum level, fermentation proceeds too fast and causes quick acidification and softening. If the salt concentration is too high, the colours and flavours are not acceptable. Salting also affects the sugars, amino acids, and micro-flora (yeasts).
Temperature: The most important factor affecting kimchi fermentation is temperature and it occurs mainly by the microorganisms naturally present in the raw materials. Although available all year round, the quality of kimchi differs depending on localities and seasons (hot summers/cold winters, summer cabbage/winter cabbage). The ripening time of kimchi depends on fermentation temperature, which then changes the pH and acidity. The optimum-ripening time and edible period of kimchi depends upon fermentation temperature and salt content. At a high temperature, the edible period is short, and at a cooler temperature, the edible period is longer. A high salt content and low temperature will result in no ripening. In tests (by KISTI), the odour, colour, and flavour scores of kimchi were higher in the samples fermented at 20°C than those at 5°C. Also in the tests, lactic-acid increased with temperature and time.
Raw Materials: The raw materials used for kimchi preparation are divided into three groups: major (ie. Chinese cabbage and radishes), sub-ingredients (spices), and optional ingredients. Dried red pepper powder, garlic, green onion, ginger, and fermented fishery products (ie. fish sauce) are the most widely used seasonings. The types and amounts of seasonings can vary, and the quality of ingredients may significantly affect fermentation and the product characteristics. Optional ingredients include leek, oysters, mustard leaves, apples/pears, and sweetener. Softer textured/higher sugar content of vegetables is desirable, however, harder textured vegetables are more favourable for long-term preservation. Sugars are used by micro-organisms for food (yeasts feed on carbon sources), and contribute greatly to the overall harmony of tastes by reducing the hotness, acidity, and the garlic odour.
The growth of microorganisms can be controlled by the addition of raw materials. Among the sub-ingredients, radishes, hot pepper powder, fermented fish, and reducing sugar can have an accelerated effect on fermentation. Garlic and leek can have a delayed effect since both are reported to have antimicrobial properties which may slow fermentation but improve storage. Both green onion and ginger can have controversial effects.
Many spices and herbs can assist in preservation by providing high antimicrobial activity against microorganisms. Peppermint, clove, cinnamon, lemon balm, horseradish, sage, and thyme are a few examples, but their specific flavours affect the taste of kimchi and are not always desired.
Microorganisms: The quality of kimchi can be controlled by desired microorganisms. During the entire stage of natural fermentation, sugars are converted to lactic-acid producing bacteria, and after a prolonged period of fermentation, various organic acids are produced by the lactic acid bacteria. After that stage, other micro-organisms including yeasts grow on the surface of kimchi, and that growth causes the softening of the texture of the ingredients.
In researching kimchi, I have found quite a few articles relating to the health benefits of the live-cultured food - much of it anecdotal - some factual. Nutrition is so complicated, and since everyone claims to be authority figure on the subject, I find it's best to make sure you check your sources before believing any of the hype put out by mainstream media, bloggers, celebrities, and pretty much anyone else with a soapbox to stand on. At the bottom of my post, I link to all the articles I used to write this blog. Ask questions - ALWAYS.
The health benefits of kimchi have been noted in many scientific, peer-reviewed articles, and it is generally accepted to be beneficial in a healthy diet. Like all fermented foods, kimchi is extraordinarily rich in beneficial bacteria- those bacteria that line the gut and help to build our immune system, manufacture and absorb vitamins. Kimchi is also a rich source of vitamin C and other antioxidants due not only to the ingredients in most kimchi recipes, but also due to the fermentation process itself which typically increases the antioxidants found in foods.
That being said, kimchi is thought to have a connection with an increased level of gastric cancers in some Koreans. In the American Journal of Clinical Nutrition, the authors state the risk may not come from the kimchi itself, but instead from the salt levels as other fermented foods such as pickles are suspected of being probable causes as well. The peer-reviewed article does make note the salt levels were never measured, only the preference for sodium. Like other cancers, hereditary issues, exercise, stress, smoking, BMI, and age can influence risks. As with other healthy diets, plenty of fresh fruits and vegetables, and unfermented soy products (non-GMO- my emphasis) may counteract the risks of consuming possible carcinogens on a once-in-a-while basis.
A healthy diet seems to contain a wide variety of foods, not too much, and mostly plants. There is no reason to eliminate kimchis (or pickles) from an otherwise sensible diet. As long as it is consumed moderately, my opinion is that the benefits outweigh any possible detriments.
How Can I Prepare Kimchi?
A good kimchi recipe balances variety, texture, flavour and heat. Vegetables should be cut into different sizes and shapes. 1-inch squares of cabbage, batons of green onions, slices of carrot, wedges of radish. A typical serving of kimchi is 1/4 c portions. Kimchi can be prepared using whole heads of cabbage, but I don't have the space to accommodate such a size. Studies have shown the sensory and nutritive traits of whole vs. cut cabbage kimchi to be negligible.
Kimchi - A Basic Recipe
Makes two litres
1 large Chinese or Napa Cabbage (about 1.5 kg)
4 L water
1/2 cup (100g) coarse salt
1 head of garlic, peeled and finely minced (about 1/8 c)
one 2-inch piece of fresh ginger, peeled and minced (about 1/8 c)
3 T fish sauce (I used a no-sugar version)
1/4 c chili paste or 1/4 cup Korean chili powder (sambal oelek or gochugaru)
1 bunch green onions, cut into 1-inch lengths (about 1 c)
1 medium daikon radish, peeled, sliced 1 cm thick then quartered (about 1 c- next time I would use more)
- Slice the cabbage lengthwise in half, then slice each half lengthwise into 3 sections. Cut away the tough stem then cut into 1- 1 1/2 inch chunks.
- Dissolve the salt in the water in a very large container, then submerge the cabbage under the water. Put a plate on top to make sure they stay under water, then let stand for 2 hours.
- Mix the other ingredients in a very large metal or glass bowl.
- Drain the cabbage, rinse it at least three times, and squeeze it dry.
- With food-safe gloves, mix the dried cabbage into the other vegetables and seasonings ensuring you coat the cabbage evenly.
- Pack the kimchi in a clean glass jar (or two) and cover it with a finger-tightened lid. Let stand for two to three days in a cool place, around room temperature. Don't worry if the kimchi is not covered by liquid at this point. As it sits, moisture will release from the vegetables.
- Check the kimchi each day. After the first day, use a spoon to compact the vegetables down into the liquid that has released. After two or three days, the kimchi should start to have a few bubbles forming inside and will have a strong odour. Once there are noticeable bubbles and the vegetables have started to expand, the kimchi should now be refrigerated. * Each day I opened the jar to release the excess gases that had formed and to taste the progress.
- After a few days or a week, the kimchi will ripen and the once harsh flavours will blend into a harmonious fermented condiment that is evenly balanced between sour, sweet, salty and spicy.
- It's advised to eat the kimchi within three weeks as the increasingly strong fermented flavours are not always palatable to North American tastes. Some kimchis are aged a year or more! Keep stored in the refrigerator.
How Do I Serve Kimchi?
So, was it worth the wait to prepare my own kimchi?
Without a doubt - absolutely.
I think I prepared my most favourite home meal ever when I dined on steamed buns stuffed with pulled pork (in the pressure cooker!) and kimchi. Breakfast the next day was not too shabby either with vermicelli noodle and edamame salad, kimchi and a poached egg.
Citations and Information Sources
Korea Institute of Science and Technology Information
David Lebovitz - Kimchi Recipe
The Art of Kimchi - Saveur.com