Editing Sauerkraut (section)

==Production==
[[File:Saurkraut (cropped).JPG|thumb|Homemade sauerkraut]]
Sauerkraut is made by a process of [[pickling]] called [[lactic acid fermentation]] that is analogous to how traditional (not heat-treated) [[pickled cucumber]]s and [[kimchi]] are made. The cabbage is finely shredded, layered with salt, and left to ferment. Fully cured sauerkraut keeps for several months in an airtight container stored at 15&nbsp;°C (60&nbsp;°F) or below. In temperate climates, this allows storage over the full winter and early-Spring. Neither refrigeration nor [[pasteurization]] is required, although these treatments prolong storage life.{{cn|date=October 2024}}

Fermentation by [[Lactobacillus|lactobacilli]] is introduced naturally, as these air-borne bacteria culture on raw cabbage leaves where they grow. Yeasts also are present, and may yield soft sauerkraut of poor flavor when the fermentation temperature is too high. The fermentation process has three phases, collectively sometimes referred to as population dynamics. In the first phase, [[anaerobic organism|anaerobic]] bacteria such as ''[[Klebsiella]]'' and ''[[Enterobacter]]'' lead the fermentation, and begin producing an acidic environment that favors later bacteria. The second phase starts as the acid levels become too high for many bacteria, and ''[[Leuconostoc mesenteroides]]'' and other ''Leuconostoc'' species take dominance. In the third phase, various ''Lactobacillus'' species, including ''[[Lactobacillus brevis|L. brevis]]'' and ''[[Lactobacillus plantarum|L. plantarum]]'', ferment any remaining sugars, further lowering the [[pH]].<ref>The pH of completely cured sauerkraut is about 3.6; see {{cite book |title=Food Chemistry |first1=H.-D. |last1=Belitz |first2=Werner |last2=Grosch |first3=Peter |last3=Schieberle |publisher=Springer |year=2009 |isbn=9783540699330 |page=803 |url=https://books.google.com/books?id=xteiARU46SQC&pg=PA803|edition=4th }}</ref> Properly cured sauerkraut is sufficiently [[acidic]] to prevent a favorable environment for the growth of ''[[Clostridium botulinum]]'', the toxins of which cause [[botulism]].<ref name="farnworth1"/><ref name="fao1"/>

A 2004 [[Genomics|genomic]] study found an unexpectedly large diversity of lactic acid bacteria in sauerkraut, and that previous studies had oversimplified this diversity. ''[[Weissella]]'' was found to be a major organism in the initial, heterofermentative stage, up to day 7. It was also found that ''[[Lactobacillus brevis]]'' and ''[[Pediococcus]] pentosaceus'' had smaller population numbers in the first 14 days than previous studies had reported.<ref>{{cite journal |author=F. BREIDT, JR. |title=A Genomic Study of ''Leuconostoc mesenteroides'' and the Molecular Ecology of Sauerkraut Fermentations |journal=Journal of Food Science |volume=69 |issue=1 |pages=30–33 |year=2004 |url=http://ddr.nal.usda.gov/bitstream/10113/15889/1/IND43655692.pdf |archive-url=https://wayback.archive-it.org/all/20120916131706/http://ddr.nal.usda.gov/bitstream/10113/15889/1/IND43655692.pdf |url-status=dead |archive-date=16 September 2012 |doi=10.1111/j.1365-2621.2004.tb17874.x |access-date=2011-01-19}}</ref>

The Dutch sauerkraut industry found that combining a new batch of sauerkraut with an old batch resulted in an exceedingly sour product. This [[sourdough]] process is known as "backslopping" or "inoculum enrichment"; when used in making sauerkraut, first- and second-stage population dynamics, important to developing flavor, are bypassed. This is due primarily to the greater initial activity of species ''L. plantarum''.<ref>{{cite book
|title=Applications of biotechnology to traditional fermented foods: report of an ad hoc panel of the Board on Science and Technology for International Development
|publisher=National Academy Press
|location=Washington, D.C.
|year=1992
|pages=15–45
|isbn=978-0-309-04685-5
|url=http://www.nap.edu/openbook.php?record_id=1939&page=15 |access-date=2011-01-19
|doi=10.17226/1939
|pmid=25121339
|author1=National Research Council (US) Panel on the Applications of Biotechnology to Traditional Fermented Foods
}}</ref>