Editing Kimchi (section)

==Production==
To make kimchi, start by slicing cabbage or daikon into small, uniform pieces to increase surface area. The pieces are then coated with salt to draw out water, which helps preserve them by preventing the growth of harmful microorganisms. This salting process can use 5–7% salt for 12 hours or 15% salt for 3–7 hours.

After salting, drain the excess water and mix in the seasoning ingredients. Adding sugar can also help by binding any remaining water. Finally, pack the brined vegetables into an airtight jar and let them ferment at room temperature for 24 to 48 hours. The ideal salt concentration during fermentation is about 3%.

Since the fermentation process results in the production of carbon dioxide, the jar should be "burped" daily to release the gas.<ref name=":3">{{cite web |title=Understanding and Making Kimchi |url=https://foodsmartcolorado.colostate.edu/recipes/preservation/understanding-and-making-kimchi/ |url-status=live |archive-url=https://web.archive.org/web/20210225084048/https://foodsmartcolorado.colostate.edu/recipes/preservation/understanding-and-making-kimchi/ |archive-date=25 February 2021 |access-date=22 February 2021 |website=Colorado Farm to Table Food Safety}}</ref> The more fermentation that occurs, the more carbon dioxide will be incorporated, which results in a very carbonated-drink-like effect.

=== Microorganisms in kimchi ===
The [[microorganism]]s present in kimchi include ''[[Bacillus mycoides]]'', ''[[Bacillus pseudomycoides|B. pseudomycoides]]'', ''[[Bacillus subtilis|B. subtilis]]'', ''[[Lactobacillus brevis]]'', ''[[Lactobacillus curvatus|Lb. curvatus]]'', ''[[Lactobacillus kimchii|Lb. kimchii]]'', ''[[Lactobacillus parabrevis|Lb. parabrevis]]'', ''[[Lactobacillus pentosus|Lb. pentosus]]'', ''[[Lactobacillus plantarum|Lb. plantarum]]'', ''[[Lactobacillus sakei|Lb. sakei]]'', ''[[Lactobacillus spicheri|Lb. spicheri]]'', ''[[Lactococcus carnosum]]'', ''[[Lactobacillus gelidum|Lc. gelidum]]'', ''[[Lactococcus lactis|Lc. lactis]]'', ''[[Leuconostoc carnosum]]'', ''[[Leuconostoc citreum|Ln. citreum]]'', ''[[Leuconostoc gasicomitatum|Ln. gasicomitatum]]'', ''[[Leuconostoc gelidum|Ln. gelidum]]'', ''[[Leuconostoc holzapfelii|Ln. holzapfelii]]'', ''[[Leuconostoc inhae|Ln. inhae]]'', ''[[Leuconostoc kimchii|Ln. kimchii]]'', ''[[Leuconostoc lactis|Ln. lactis]]'', ''[[Leuconostoc mesenteroides|Ln. mesenteroides]]'', ''[[Serratia marcescens]]'', ''[[Weissella cibaria]]'', ''[[Weissella confusa|W. confusa]]'', ''[[Weissella kandleri|W. kandleri]]'', ''[[Weissella kimchii|W. kimchii]]''. ''[[Weissella koreensis|W. koreensis]]'', and ''[[Weissella soli|W. soli]]''.<ref>{{Cite book|url=https://books.google.com/books?id=ZtoNDgAAQBAJ&pg=PT17|title=Lactic Acid Fermentation of Fruits and Vegetables|last1=Paramithiotis|first1=Spiros|last2=Papoutsis|first2=George|last3=Drosinos|first3=Eleftherios H.|publisher=[[CRC Press]]|year=2017|isbn=978-1-4987-2690-0|editor-last=Paramithiotis|editor-first=Spiros|location=Boca Raton, FL|pages=5}}</ref><ref name=pmid15992614>{{cite journal |doi=10.1016/j.ijfoodmicro.2004.12.010 |pmid=15992614 |title=Analysis of kimchi microflora using denaturing gradient gel electrophoresis |journal=International Journal of Food Microbiology |volume=102 |issue=2 |pages=143–150 |year=2005 |last1=Lee |first1=Jung-Sook |last2=Heo |first2=Gun-Young |last3=Lee |first3=Jun Won |last4=Oh |first4=Yun-Jung |last5=Park |first5=Jeong A. |last6=Park |first6=Yong-Ha |last7=Pyun |first7=Yu-Ryang |last8=Ahn |first8=Jong Seog }}</ref><ref name=pmid16553862>{{cite journal |doi=10.1111/j.1574-6968.2006.00186.x |pmid=16553862 |title=Microbial population dynamics of kimchi, a fermented cabbage product |journal=FEMS Microbiology Letters |volume=257 |issue=2 |pages=262–267 |year=2006 |last1=Cho |first1=Jinhee |last2=Lee |first2=Dongyun |last3=Yang |first3=Changnam |last4=Jeon |first4=Jongin |last5=Kim |first5=Jeongho |last6=Han |first6=Hongui |doi-access=free }}</ref><ref name=pmid18562030>{{cite journal |doi=10.1016/j.ijfoodmicro.2008.05.013 |pmid=18562030 |title=Analysis of yeast and archaeal population dynamics in kimchi using denaturing gradient gel electrophoresis |journal=International Journal of Food Microbiology |volume=126 |issue=1–2 |pages=159–166 |year=2008 |last1=Chang |first1=H. |last2=Kim |first2=K. |last3=Nam |first3=Y. |last4=Roh |first4=S. |last5=Kim |first5=M. |last6=Jeon |first6=C. |last7=Oh |first7=H. |last8=Bae |first8=J. }}</ref><ref name=pmid23558201>{{cite journal |doi=10.1016/j.ijfoodmicro.2013.02.022 |pmid=23558201 |title=Metatranscriptomic analysis of lactic acid bacterial gene expression during kimchi fermentation |journal=International Journal of Food Microbiology |volume=163 |issue=2–3 |pages=171–179 |year=2013 |last1=Jung |first1=Ji Young |last2=Lee |first2=Se Hee |last3=Jin |first3=Hyun Mi |last4=Hahn |first4=Yoonsoo |last5=Madsen |first5=Eugene L. |last6=Jeon |first6=Che Ok }}</ref><ref name=pmid23550842>{{cite journal |doi=10.1111/1750-3841.12095 |pmid=23550842 |title=Microbial Succession and Metabolite Changes during Long-Term Storage of Kimchi |journal=Journal of Food Science |volume=78 |issue=5 |pages=M763–M769 |year=2013 |last1=Jeong |first1=Sang Hyeon |last2=Lee |first2=Se Hee |last3=Jung |first3=Ji Young |last4=Choi |first4=Eun Jin |last5=Jeon |first5=Che Ok }}</ref><ref name=pmid23587713>{{cite journal |doi=10.1016/j.ijfoodmicro.2013.03.016 |pmid=23587713 |title=Microbial succession and metabolite changes during fermentation of dongchimi, traditional Korean watery kimchi |journal=International Journal of Food Microbiology |volume=164 |issue=1 |pages=46–53 |year=2013 |last1=Jeong |first1=Sang Hyeon |last2=Jung |first2=Ji Young |last3=Lee |first3=Se Hee |last4=Jin |first4=Hyun Mi |last5=Jeon |first5=Che Ok }}</ref><ref name=pmid23314371>{{cite journal |doi=10.4014/jmb.1210.10002 |pmid=23314371 |title=Comparison of Bacterial Community Changes in Fermenting Kimchi at Two Different Temperatures Using a Denaturing Gradient Gel Electrophoresis Analysis |journal=Journal of Microbiology and Biotechnology |volume=23 |issue=1 |pages=76–84 |year=2013 |last1=Hong |first1=Yeun |last2=Yang |first2=H. S. |last3=Chang |first3=H. C. |last4=Kim |first4=H. Y. |s2cid=13462137 |url=http://pdfs.semanticscholar.org/2146/19a579c602ceeb7d56975ae35e9fca36f23a.pdf |archive-url=https://web.archive.org/web/20190220083800/http://pdfs.semanticscholar.org/2146/19a579c602ceeb7d56975ae35e9fca36f23a.pdf |url-status=dead |archive-date=20 February 2019 }}</ref> [[Archaea]] and [[yeast]]s, such as Saccharomyces, Candida, Pichia, and Kluyveromyces are also present in kimchi,<ref name=":9">{{Cite journal|last1=Jung|first1=Ji Young|last2=Lee|first2=Se Hee|last3=Jeon|first3=Che Ok|date=14 January 2014|title=Kimchi microflora: history, current status, and perspectives for industrial kimchi production|url=http://dx.doi.org/10.1007/s00253-014-5513-1|journal=Applied Microbiology and Biotechnology|volume=98|issue=6|pages=2385–2393|doi=10.1007/s00253-014-5513-1|pmid=24419800|s2cid=13085302|issn=0175-7598|access-date=4 August 2021|archive-date=17 March 2024|archive-url=https://web.archive.org/web/20240317211858/https://link.springer.com/article/10.1007/s00253-014-5513-1|url-status=live}}</ref><ref>{{cite journal |last1=Chang |first1=HW |last2=Kim |first2=KH |last3=Nam |first3=YD |last4=Roh |first4=SW |last5=Kim |first5=MS |last6=Jeon |first6=CO |last7=Oh |first7=HM |last8=Bae |first8=JW |title=Analysis of yeast and archaeal population dynamics in kimchi using denaturing gradient gel electrophoresis. |journal=International Journal of Food Microbiology |date=15 August 2008 |volume=126 |issue=1–2 |pages=159–66 |doi=10.1016/j.ijfoodmicro.2008.05.013 |pmid=18562030}}</ref> with the latter being responsible for undesirable white colonies that sometimes form in the product as well as food spoilages and off-flavors.<ref name=":9" /><ref>{{cite journal |last1=Kim |first1=JY |last2=Kim |first2=J |last3=Cha |first3=IT |last4=Jung |first4=MY |last5=Song |first5=HS |last6=Kim |first6=YB |last7=Lee |first7=C |last8=Kang |first8=SY |last9=Bae |first9=JW |last10=Choi |first10=YE |last11=Kim |first11=TW |last12=Roh |first12=SW |title=Community structures and genomic features of undesirable white colony-forming yeasts on fermented vegetables. |journal=Journal of Microbiology (Seoul, Korea) |date=January 2019 |volume=57 |issue=1 |pages=30–37 |doi=10.1007/s12275-019-8487-y |pmid=30392155|s2cid=53219410 }}</ref>

In early fermentation stages, the ''[[Leuconostoc]]'' variety is found more dominantly in kimchi fermentation because of its lower acid tolerance and microaerophilic properties; the ''[[Leuconostoc]]'' variety also grows better at low salt concentrations.<ref name=":9" /> Throughout the fermentation process, as acidity rises, the ''[[Lactobacillus]]'' and ''[[Weissella]]'' variety become dominant because of their higher acid tolerance. ''Lactobacillus'' also grows better in conditions with a higher salt concentration.<ref name=":9" />

These microorganisms are present due to the natural microflora provided by utilizing unsterilized food materials in the production of kimchi.<ref name=":0">{{Cite journal|last1=Lee|first1=Mo-Eun|last2=Jang|first2=Ja-Young|last3=Lee|first3=Jong-Hee|last4=Park|first4=Hae-Woong|last5=Choi|first5=Hak-Jong|last6=Kim|first6=Tae-Woon|date=28 May 2015|title=Starter Cultures for Kimchi Fermentation|journal=Journal of Microbiology and Biotechnology|language=en|volume=25|issue=5|pages=559–568|doi=10.4014/jmb.1501.01019|pmid=25674806|issn=1017-7825|doi-access=free}}</ref><ref name=":1">{{Cite book|url=https://www.ncbi.nlm.nih.gov/books/NBK234703/|title=Lactic Acid Fermentations|last=Foods|first=National Research Council (US) Panel on the Applications of Biotechnology to Traditional Fermented|date=1992|publisher=National Academies Press (US)|language=en|access-date=8 August 2019|archive-date=1 April 2015|archive-url=https://web.archive.org/web/20150401052540/https://www.ncbi.nlm.nih.gov/books/NBK234703/|url-status=live}}</ref> The step of salting the raw materials as well as the addition of red pepper powder inhibits the pathogenic and putrefactive bacteria present in the microflora, allowing the [[lactic acid bacteria]] (LAB) to flourish and become the dominant microorganism.<ref name=":0" /><ref>{{Cite journal|last1=Park|first1=Kun-Young|last2=Jeong|first2=Ji-Kang|last3=Lee|first3=Young-Eun|last4=Daily|first4=James W.|date=January 2014|title=Health Benefits of Kimchi (Korean Fermented Vegetables) as a Probiotic Food|journal=Journal of Medicinal Food|language=en|volume=17|issue=1|pages=6–20|doi=10.1089/jmf.2013.3083|pmid=24456350|issn=1096-620X}}</ref> These anaerobic microorganisms steadily increase in number during the middle stages of fermentation, and prefer to be kept at low temperatures of about 10°C, pH of 4.2-4, and remain in the presence of 1.5% – 4% NaCl.<ref name=":9" /><ref name=":0" /> A faster fermentation at a higher temperature may be chosen as well to accelerate the growth of bacterial cultures for a faster decrease in pH level.<ref name=":9" />

Since the raw cruciferous vegetables themselves are the source of LAB required for fermentation, no starter culture is required for the production of kimchi; rather, spontaneous fermentation occurs.<ref name=":2">{{Cite journal|last1=Jung|first1=Ji Young|last2=Lee|first2=Se Hee|last3=Kim|first3=Jeong Myeong|last4=Park|first4=Moon Su|last5=Bae|first5=Jin-Woo|last6=Hahn|first6=Yoonsoo|last7=Madsen|first7=Eugene L.|last8=Jeon|first8=Che Ok|date=1 April 2011|title=Metagenomic Analysis of Kimchi, a Traditional Korean Fermented Food|journal=Applied and Environmental Microbiology|language=en|volume=77|issue=7|pages=2264–2274|doi=10.1128/AEM.02157-10|issn=0099-2240|pmc=3067442|pmid=21317261|bibcode=2011ApEnM..77.2264J}}</ref> The total population of microorganisms present at the beginning of processing determines the outcome of fermentation, causing the final product to be highly variable in terms of quality and flavor.<ref name=":0" /> Currently, there are no recommended approaches to control the microbial community during fermentation to predict the outcome.<ref name=":2" /> In the industrial production of kimchi, starter cultures made up of ''[[Leuconostoc mesenteroides|Leu. mesenteroides]]'', ''[[Leuconostoc citreum|Leu. citreum]]'', and ''[[Lactiplantibacillus plantarum|Lb. plantarum]]'' are used, which are often unsuccessful because they fail to outcompete the naturally occurring cultures on the raw materials.<ref name=":9" />

=== By-products of microorganisms ===
The [[lactic acid bacteria]] (LAB) produce [[lactic acid]], [[hydrogen peroxide]], and [[carbon dioxide]] as by-products during metabolism. Lactic acid quickly lowers the pH, creating an acidic environment that is uninhabitable for most other microorganisms that survived salting.<ref name=":1" /> This also modifies the flavor of sub-ingredients and can increase the nutritive value of the raw materials, as the microbial community in the fermentation process can synthesize B vitamins and hydrolyze cellulose in plant tissues to free nutrients that are normally indigestible by the human gastrointestinal tract.<ref name=":1" /> Hydrogen peroxide is formed by the oxidation of reduced [[nicotinamide adenine dinucleotide]] (NADH) and provides an antibiotic to inhibit some undesirable microorganisms.<ref name=":1" /> Carbon dioxide functions as a preservative, flushing out oxygen to create an anaerobic environment, as well as creating the desired carbonation in the final product.<ref name=":1" />

=== Odor ===
Kimchi is known for its strong, spicy, flavors and odors, although milder varieties exist. Variations in the fermentation process cause the final product to be highly variable in terms of quality and flavor.<ref name=":0" /> The strong odor is especially tied to the sulfur compounds from garlic and ginger of kimchi, which can be less appealing to non-Koreans. Thus, scientists are experimenting with the types of bacteria used in its production to minimize the odor to increase the appeal to international markets.<ref name="Fifield_6/22/2017">{{cite news | last=Fifield | first=Anna | title=To promote kimchi abroad, Korean scientists are trying to get rid of the smell | newspaper=[[The Washington Post]] | date=22 June 2017 | url=https://www.washingtonpost.com/world/asia_pacific/to-promote-kimchi-abroad-korean-scientists-are-trying-to-get-rid-of-the-smell/2017/06/21/a1cc7de2-4ab7-11e7-b69d-c158df3149e9_story.html | access-date=16 November 2021 | archive-date=29 March 2021 | archive-url=https://web.archive.org/web/20210329095725/https://www.washingtonpost.com/world/asia_pacific/to-promote-kimchi-abroad-korean-scientists-are-trying-to-get-rid-of-the-smell/2017/06/21/a1cc7de2-4ab7-11e7-b69d-c158df3149e9_story.html | url-status=live }}</ref> These efforts are not universally appreciated by lovers of kimchi, as the flavor is affected in the process, and some see that "South Korea's narrative about its own culinary staple" is being manipulated to suit the foreigners' tastes.<ref name="Herreria_Russo_6/29/2017">{{cite web | last=Herreria Russo | first=Carla | title=Korean Scientists Are Making Kimchi Less Smelly For Westerners, And People Are Pissed | website=[[HuffPost]] | date=29 June 2017 | url=https://www.huffpost.com/entry/south-korea-kimchi-less-smelly_n_5954422ae4b05c37bb7bdc02 | access-date=16 November 2021 | archive-date=16 November 2021 | archive-url=https://web.archive.org/web/20211116164657/https://www.huffpost.com/entry/south-korea-kimchi-less-smelly_n_5954422ae4b05c37bb7bdc02 | url-status=live }}</ref>