Sauerkraut is a mixture of salt and shredded cabbage that is allowed to ferment. The amount of salt is critical to assuring food safety and should not be adjusted.
Fermentation takes three to six weeks depending on the air temperature. During this time, the acidity in the product increases. Once the sauerkraut is fermented, it may be canned or frozen.
Suitable Cabbage Varieties
Sauerkraut can be made from all cabbage varieties; however, some varieties are better suited than others. Typically, cabbage heads grown for processing are much larger than those grown for the fresh market. Sauerkraut makers are encouraged to try new varieties as well. Mature heads weighing 6–15 pounds with a solid, white interior are most desirable. Additionally, cabbage harvested later in the season may contain more sugars that support the growth of bacteria during fermentation. Head size (small to large), shape (round, flat, conical, and variations), density, and color (green, blue-green, or red), as well as leaf texture (smooth or savoy) should all be considered. Wrapper leaves (number, thickness, and tightness) and core length can also vary among varieties.
Varieties to consider include:
Danish Ballhead. A mid-season heirloom variety with a pleasing flavor and texture.
Premium Late Dutch. A late-season variety with 10–15-pound heads, excellent for fall or winter use.
Stone Head. Very early, small head.
Early Flat Dutch. Early, round head.
Head Start. Early, medium-size head with excellent field holding for an early type.
Hinova. Late variety, flat, rounded head.
Red Acre. 3-pound head, red variety.
Ingredients and Materials
- 25 pounds fresh cabbage
- ¾ cup canning salt
- fermentation vessel
Fermentation vessels should be made of stone, glass, or food-grade plastic. A 1-gallon container will be appropriate for up to 5 pounds of cabbage. Crocks should not be cracked or lined with metal. Containers made of aluminum, copper, brass, iron, galvanized metal, or trash cans are not appropriate. Prior to fermentation, containers should be washed with warm water and soap. Clean containers not made of food-grade materials can be used if a food-grade plastic liner is used. Trash bags are not food-grade plastic liners.
Preparation Instructions
Working with 5 pounds of cabbage at a time, discard outer leaves, and then rinse the cabbage in cold, clean water to remove soil or debris. Cut the head of cabbage into pieces and remove the center core. Shred into long, thin strips, about the thickness of a quarter.
Combine 5 pounds of cabbage with 3 tablespoons of canning salt and mix well. Repeat this process until you have combined 25 pounds of cabbage and ¾ cup of canning salt. Transfer this mixture to a suitable container (see below). There should be 4–5 inches of headspace left at the top of the container. The cabbage should be completely covered with liquid. If there is not enough juice from the shredded cabbage to cover the cabbage, make a salt brine with 1 quart of water and 1½ tablespoons of canning salt. Pickling or canning salt is preferable since it does not contain iodine or anti-caking agents. The brine should be boiled and then cooled to room temperature before adding to your cabbage mixture.
Suitable Container:
Stoneware crock, large glass jar, or food-grade plastic container. Do not use trash cans, aluminum, copper, brass, galvanized, or iron containers.
Weigh down the cabbage to keep it submerged in the liquid. A heavy plate or lid that fits inside the container can be used. Alternatively, use a double layer of food-grade plastic bags, such as re-sealable gallon-size freezer bags, and fill the top bag with brine for weight.
The cabbage should be covered with 1–2 inches of brine. Keeping the cabbage protected from oxygen helps limit mold growth during fermentation.
Fermentation
During the fermentation process, store the sauerkraut at 70–75 degrees Fahrenheit. At this temperature, your sauerkraut should be fully fermented in about three to four weeks. At 60–65 F, the fermentation process may take five to six weeks. If the temperature is above 75 F, the sauerkraut may become soft and lack flavor. If the temperature is below 60 F, fermentation may be sluggish, and the proper acidity may not be achieved.
During fermentation, the lactic acid bacteria (the same microbes that make yogurt) grow in the high-salt environment and produce acid and flavors associated with fermented vegetables. Lactic-acid bacteria are found naturally on the surface of vegetables. Unlike other fermented foods, it is unnecessary to add lactic acid bacteria cultures. The added salt and the acid produced by the bacteria will help control pathogenic bacterial contamination. Consequently, salt levels cannot be reduced in fermented vegetable preparations, and salt substitutes cannot be used. The acid produced during the fermentation is what preserves the product.
Lactic acid bacteria produce a variety of flavorful byproducts during fermentation. The most important of these is lactic acid, which contributes to the tartness and preservation of the finished kraut. However, the bacteria also make other acids and flavors as they grow. The temperature at which the sauerkraut is stored impacts the development of these flavors and the lactic acid. At lower temperatures, growth occurs more slowly. Therefore, the fermentation process often takes longer when the sauerkraut is stored under cooler conditions.
When using a heavy plate, lid, or jar to weigh down the cabbage, you need to check the sauerkraut two to three times a week and remove any scum that forms. A thin film of yeast or mold (scum) may form on the surface of the fermentation brine. When using a brine-filled bag as the weight, do not disturb the container until normal fermentation is completed (when the bubbling stops).
Preservation Methods:
Chopped cabbage should be weighed to add the appropriate amount of salt for the fermentation. Once the fermentation is complete, the sauerkraut can be canned, refrigerated, or frozen.
Preserving Sauerkraut
Raw pack by filling jars with sauerkraut and cover with juices, leaving ½-inch of headspace. Wipe the jar rims; adjust the lids, and process in a boiling water bath. See Table 1 for processing times based on altitude recommendations. Begin timing once the water bath has returned to a full boil.
Hot pack the sauerkraut by bringing it and the liquid to a boil, stirring frequently. Remove from heat, fill the jars, leaving ½-inch of headspace, wipe the jar rims, adjust the lids, and process in a boiling water bath. See Table 1 for processing times based on altitude recommendations. Begin timing once the water bath has returned to a full boil.
Freeze by filling pint- or quart-size freezer bags, or reusable ridge plastic freezer containers, leaving at least 3 inches of room for expansion during freezing. Squeeze out air, seal, and label. Freeze for eight to 12 months.
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Additional Resources
Learn more about preserving sauerkraut:
- National Center for Home Food Preservation
- Sauerkraut: From Garden to Table, North Dakota State University
- USDA Complete Guide to Home Canning
Originally written December 14, 2017, by Treva Williams, Extension Educator, Family and Consumer Sciences, Ohio State University Extension; Abigail Snyder, Field Specialist, Family and Consumer Sciences, Ohio State University Extension; and Brad Bergefurd, Extension Educator, Agriculture and Natural Resources, Ohio State University Extension.