The word sauerkraut translates to "sour cabbage," which refers both to its taste and method of preparation. The souring, or fermenting, process must be controlled to produce a palatable, texturally pleasing batch of sauerkraut. One of the most important aspects of curing sauerkraut is the temperature, which determines the quality and timeliness of the finished product. Sauerkraut will successfully cure between 70 and 75 degrees Fahrenheit with higher or lower temperatures yielding vastly different results, if it ferments at all.
The Basics of Curing Sauerkraut
Sauerkraut is a simple preparation, although it takes precision in its execution to produce high quality product. The cabbage must be shredded to a uniform size and coated with canning salt to draw out its natural moisture. Once wilted, the shredded cabbage is firmly packed into a sanitized crock or other wide-mouthed, non-metallic container. The cabbage must be submerged in its own juices because air prevents fermentation and encourages spoilage. If the cabbage fails to produce sufficient moisture, a simple brine of 2 percent to 3 percent canning salt and water can be used to make up the deficit. Weigh the cabbage down with a water-filled freezer bag, then place the crock in an out-of-the-way area to ferment.
Impact of Extreme Temperatures
The 70- to 75-degree Fahrenheit temperature used to cure sauerkraut creates a final product with a golden color, tangy flavor and a delicate texture. Cold temperatures slow fermentation or it may prevent it entirely by discouraging the proliferation of microorganisms responsible for converting the cabbage's natural sugars into lactic acid. However, if fermentation does occur, the sauerkraut will likely be of adequate quality. Temperatures higher than 75 F have a devastating impact of sauerkraut. They cause extremely rapid fermentation and the overproduction of bacteria. The resulting sauerkraut will be soft or squishy with a dark, cloudy appearance and an unpleasant smell.
Sauerkraut will ferment in roughly three to four weeks if stored at the appropriate temperature range. Temperatures between 60 to 65 F increase the fermentation time to five to six weeks, while temperatures below 60 F can prolong the process to up to six months or stop it entirely. Sauerkraut stored at higher temperatures produces an abundance of bacteria, so it will ferment or spoil in as little as seven to ten days. The resulting product will be of poor quality and it may harbor bacteria that makes it unsafe for consumption.
Signs of Spoilage
Bacteria is the driving force behind fermentation, although it must be controlled to prevent unhealthy bacterial growth. Sauerkraut cured at higher temperatures often contains an unsafe level of bacteria or potentially harmful microorganisms. Fortunately, such rampant bacterial growth produces unmistakable signs. Mushiness and darkening are the two most common signs of improperly stored sauerkraut, although it may also develop visible mold on the surface or a strong, disagreeable odor. Spoiled sauerkraut must not be eaten or used, and it should be discarded immediately.
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