Wait until late fall to make the best sauerkraut. Cold-weather cabbage contains more natural sugars needed for the fermentation process.
Sauerkraut is the result of natural fermentation by bacteria in cabbage in the presence of a salt solution. Lactic acid and other minor products of fermentation give sauerkraut its characteristic flavor and texture.
If possible, prepare the cabbage and start the fermentation the day the cabbage is harvested. A 5-gallon container holds about 25 pounds of cabbage. Shred cabbage 1/16th-inch thick, about the thickness of a quarter. Cut the cabbage using a slaw cutter, a meat slicer or a food processor. (Not all food processors will give an even shred.) Cabbage needs to be broken up enough to bruise the cells to release the sugars.
What Salt Should I Use?
Use only canning or pickling salt. Iodized salt and sea salt may cause discoloration. The proper balance of salt and cabbage prevents the growth of spoilage organisms and pathogens while promoting the activity of lactic-acid producing bacteria. Salt draws water and sugars from the cabbage and produces a brine that should cover the cabbage when it is packed into the brining container. Use a stainless steel, glass or food-grade plastic container. The container may be lined with a large, food-grade plastic bag. Do not use garbage bags or trash can liners.
Filling Your Container With Sauerkraut
Fill the container with 5 pounds of shredded cabbage and 3 tablespoons salt. Don’t reduce the amount of salt. Mix thoroughly to avoid pockets of low or high salt concentration. The salt draws moisture from the cabbage. Tamp it down to release juices and eliminate air pockets. Repeat in 5 pound increments until the container is filled to within 3 to 4 inches from the top. Keep the cabbage submerged in the brine at all times to keep oxygen out and prevent mold growth. Only if the juice does not cover the cabbage, add boiled and cooled brine prepared with 1-1/2 tablespoons of salt in a quart of water.
Cover the sauerkraut with a large food grade plastic bag filled with salt water (4-1/2 tablespoons salt and 3 quarts water.) It is a good idea to place the brine filled bag inside another bag. Cover the top of the container with a clean kitchen towel to reduce exposure to airborne mold spores. If you weight the cabbage with a brine-filled bag, it is not necessary to disturb the container until normal fermentation is complete. If you use jars on a plate as weights, you must check the sauerkraut two to three times each week and remove scum if it forms.
The Fermentation Process
During fermentation, a series of changes takes place when the salt and acid-tolerant bacteria release acids that raise the acidity and create ideal conditions for other bacteria to further ferment the sauerkraut. Fermentation naturally stops when the sauerkraut reaches the proper acidity.
Temperature affects the speed of fermentation. Between 60 F and 65 F, it will take 6 weeks to make sauerkraut. The ideal temperature is between 70 F and 75 F, at which point it will ferment properly in 3 to 4 weeks. Above 80 F, sauerkraut may become soft and spoil.
Checking Your Sauerkraut Before Eating
Sauerkraut is ready to use when it reaches the desired tartness. Do not taste it if you see mold on the surface, feel a slimy texture, or smell a bad odor.
Fully fermented sauerkraut may be kept tightly covered in the refrigerator for several months, or, it may be canned or frozen.
Sauerkraut and its liquid can be heated slowly to a boil and packed firmly into jars making sure to cover the solids with juices. If there is not enough juice to cover the cabbage in each jar, add boiled and cooled brine prepared with 1-1/2 tablespoons of salt in 1 quart of water. Allow 1/2 inch headspace. Process hot-packed pints for 10 minutes and quarts 15 minutes in a boiling water bath. Adjust times for higher altitudes.
Making a Raw Pack
To make a raw pack, fill the jars firmly with unheated sauerkraut and cover with juices. Process raw-packed pints for 20 minutes and quarts for 25 minutes in a boiling water bath.
To freeze the sauerkraut, simply fill pint or quart-size freezer bags, rigid plastic freezer containers or tapered freezer jars. If you eat sauerkraut for its probiotics, you need to know that the heat generated in canning sauerkraut will destroy living probiotics; freezing it will preserve the probiotics.
If you have a food preservation question, contact your local Penn State Extension office and they will forward it to the proper educator.