Sauerkraut, raw, unpasteurized, organic? (Sauerkraut)

To make raw sauerkraut ( sauerkraut ), you use pointed or white cabbage ( Brassica oleracea convar. capitata var. alba ), which is fermented with the help of lactic acid bacteria. Raw, unpasteurized sauerkraut is a very valuable foodstuff for health reasons.

Use in the kitchen

Can you eat sauerkraut raw? Yes, cooking raw sauerkraut would actually be a shame, wasting its valuable ingredients (see effects on health ).

The preparation is simple, because eating sauerkraut raw is most valuable: e.g. as a salad mixed with other vegetables or fruit and marinated with oil (e.g. rapeseed oil or linseed oil ) andpepper . The addition of salt and vinegar is not necessary, as sauerkraut is salted during production and brings acidity through fermentation. If sauerkraut is too sour for you, you can rinse it briefly with water beforehand. The taste can also be softened by adding apples, pears, grapes, but also root vegetables such as carrots or beetroot . Vegan sweet or sour cream also has a balancing effect.

Classic spices for raw sauerkraut are juniper berries, cloves, pepper, marjoram, caraway, bay leaves or sometimes mint, rosemary, fennel seeds or savory, tarragon . Raw sauerkraut also tastes good without any additional spices or processing.

Homemade

Ingredients: a white cabbage, salt (preferably natural without additives), approx. 500 ml boiled and cooled water with 2% salt. ²

Optional ingredients: dill, horseradish, caraway seeds, mustard seeds, coriander seeds, allspice, juniper berries, garlic ,black pepper, a small beetroot or some red cabbage .

Boiled utensils: a large bowl and a large swing-top jar, fermentation jar or fermentation pot.

Preparation: What is important when making sauerkraut is hygiene, exclusion of air (anaerobic conditions), salt concentration and temperatures that are neither too high nor too low; then not much can go wrong.

First remove the outer leaves of the cabbage, wash them and put them aside; you will need them later. Also wash the outside of the cabbage head with water; to remove harmful bacteria from the field or transport.

Quarter the cabbage and remove the stalk. Now chop the cabbage into fine strips using a vegetable slicer or a sharp knife. Weigh the whole thing and calculate two percent of it; this gives you the amount of salt you need. Mix the weighed salt evenly with the cabbage. Put about a quarter of the cabbage into the fermentation vessel, press it well into the vessel with clean hands and add some of the optional spices. Now you can press horseradish or beetroot slices onto it. Repeat the whole process until the cabbage is used up or the fermentation vessel is filled to a maximum of 15 cm below the rim. Within the next hour, enough liquid should form to submerge the vegetables. It is essential that the cabbage remains submerged during the entire fermentation time. If there is too little liquid, add the prepared brine. The cabbage should be covered with about 5 cm of liquid.

Now you have to weigh down the cabbage. Otherwise it will rise to the surface during fermentation and spoil through contact with oxygen. You can buy special weights or you can use a small sterilized jar. Place the cabbage leaves that you put aside at the beginning under the weight. You should keep an eye on the weight for the first few days, as the _CO2 gas that is produced can push the weight up or move it. The cabbage can now ferment for around two weeks at room temperature (around 20 °C). You have to check every day that no cabbage is sticking out of the liquid and let off the gases, unless you have used a special fermentation vessel. Then put the raw sauerkraut in the fridge.

Tips: Suitable containers are glazed ceramic containers, glass and stainless steel. Aluminium, iron and plastic (with the exception of containers made specifically for this purpose) are not suitable . For a 10-litre fermentation pot, calculate a quantity of 9 kg of raw cabbage. This means that you will buy a good 11 kg of cabbage to compensate for the parts that have been removed.

Hygiene is a key aspect of successful sauerkraut. Everything that comes into contact with the cabbage must be clean: knives, containers, hands, etc. Otherwise, mold can form or yeast can take over and ruin the batch of sauerkraut. This can easily happen the first time you try it, so start with small amounts.

The choice of cabbage also makes a difference. Cabbage wrapped in plastic from the refrigerator shelf is a bad choice; the cabbage is probably already covered in microorganisms that cause it to spoil. Buy cabbage that is as fresh as possible, unpacked and not from the refrigerator. Sauerkraut beginners are on the safe side with firm, dense heads of cabbage. If you remove the outer leaves, mold is less likely. Pre-made starter cultures from the store also give you a little more certainty that you will end up with good, healthy and long-lasting sauerkraut.

The sauerkraut juice produced during the production of raw sauerkraut is also very valuable.

Vegan recipe for raw sauerkraut salad

Ingredients (4 servings): 500 g fresh raw sauerkraut, 250 g carrots, 3 spring onions (winter onions), 2 small sour apples, 3 tbsp lemon juice, 1⁄2 bunch of dill, 5 tbsp vinegar, salt,pepper, 5 tbsp rapeseed oil, 1 piece of lettuce ( endive orlettuce ).

Preparation: Roughly chop the sauerkraut, wash, peel and finely grate the carrots. Wash the spring onions and cut into fine rings. Wash the apples, remove the core, cut into thin slices and sprinkle with lemon juice. For the marinade, wash the dill, pat dry and finely chop. Mix vinegar with salt (depending on taste), pepper, sugar, dill and oil. Pour the seasoned marinade over the prepared ingredients, mix loosely and leave to infuse for about 30 minutes. In the meantime, wash the lettuce or endive and pat dry (or spin) and arrange on a plate. Spread the raw vegetable and sauerkraut mixture on top and enjoy.

Goes well with: Burgers, e.g. raw vegan Zuccoti Park Burger with sweet potatoes .

Vegan recipes with sauerkraut can be found under the note: " Recipes that have the most of this ingredient ".

Purchasing - Storage

You will look in vain for unpasteurized sauerkraut in large supermarket chains such as Lidl, Rewe, Edeka, Coop, Migros, Denner, Volg, Spar, Aldi, Hofer, Billa, Denn's Biomarkt or Alnatura . You will generally only find conventionally preserved, i.e. pasteurized sauerkraut . Nowadays, however, fresh sauerkraut in raw food quality is increasingly available in organic shops, health food stores, drugstores, at the weekly market or on the Internet. Direct sellers also sell it loose/unpacked at markets. Unfortunately, it remains the exception that you can buy sauerkraut in raw food quality (not heated above 42 °C), with lactic acid bacteria still alive.

A product that contains living microorganisms is of course much more complicated and expensive to sell than a stable pasteurized product. This is why raw sauerkraut is mainly found in small, regional health food stores. And even there it is quite rare, but usually in organic quality. With a little research and a higher budget for food, you can buy raw sauerkraut. But you can also prepare raw sauerkraut inexpensively and well at home, as described above. In Central Europe, white cabbage is in season from June to March, with the main season being autumn. This is why you can buy organic sauerkraut (raw) or make it yourself/store it whenever you feel like it. Because of its long shelf life, it is (theoretically) available all year round.

The availability of raw sauerkraut varies depending on the size of the store, catchment area, etc. Our recorded food prices for the DA-CH countries can be found above under the ingredient image - and by clicking you can see their development at various suppliers.

Storage tips

If it is stored hygienically and cool and protected from air, raw sauerkraut will stay edible for an average of six months. Since it is a living product, you have to constantly use your senses to test whether the sauerkraut is still good.

How can you tell if sauerkraut is spoiled? You can usually smell or see whether the cabbage is spoiled. Mold is one sign that the cabbage is no longer suitable for consumption. Other warning signs are:

Dark cabbage: If the weight fails to weigh down the sauerkraut so that the liquid does not seal the cabbage airtight, certain bacteria and yeasts can grow that discolor the cabbage close to the surface. If there is too little liquid in the cabbage, the salt distribution can be uneven. Black spots appear in the cabbage, caused by spoilage bacteria. If the salt concentration is too high, the bacteria needed for fermentation can no longer live. In the dark spots, up to 9% salt could be found, and in the same batch, spots with only 0.6%. Sufficient liquid prevents this problem!

Pink cabbage: The cabbage can turn pink to red when air gets into it. This is because it is a specific type of aerobic yeast. If you leave sauerkraut open, a white layer of yeast will almost always develop on the liquid. Occasionally, especially when the salt concentration is high, a pink yeast variant will develop. The pink color then slowly mixes with the remaining liquid in the cabbage. Even in areas where the cabbage is not compact enough in the container, small air-salt pockets can form, which allow the pink yeast variant to thrive.

Soft kraut: This spoilage is also related to the presence of air, salt concentration, high temperature and the associated faulty fermentation. Soft kraut can also occur if the fermentation does not take place in the right order. The causes are too high temperatures and too little salt.

Slimy herb: Slimy, viscous herb is rare. Certain (non-gas-producing) lactic acid bacteria, L. cocumeris and L. plantaru, can be the cause. They grow particularly quickly at higher temperatures. The slime can dissolve through further fermentation or heating.

Rotten cabbage: Bacteria, yeast, mold or fruit flies can cause the cabbage to rot; it smells and is inedible. The cabbage can appear soft and black or completely fall apart. The unappetizing taste spreads throughout the cabbage. The cabbage must always be moist and protected from insects and aerobic microorganisms. The utmost cleanliness is required when making sauerkraut.

Off-flavors: The flavor depends on the bacteria and the order in which they are created. The flavor can be OK, but still not very good. For example, non-gas-producing lactic acid bacteria, if allowed to grow too early, can produce a sharp, acrid or bitter flavor. Fermentation that is too fast can make the cabbage taste raw; the typical hearty sauerkraut flavor could not develop.

In general, sauerkraut improves in taste over time, but only if the salt concentration (approx. 2.5%), temperature (15–25 °C) and hygiene measures are chosen carefully. ^{3, 4}

In a 2022 dissertation, a prospective PhD student investigated pathogens in sauerkraut. She concluded that salt, lactic acid bacteria (LAB), and the acidic environment in traditional sauerkraut fermentation exclude the growth of all foodborne bacterial pathogens, including potential acid-tolerant pathogens such as E. coli O157 and L. monocytogenes. ¹⁴

The low pH value, the high salt concentration and the exclusion of oxygen, together with storage in the refrigerator, makes sauerkraut a safe food, despite the presence of living microorganisms.

Ingredients - Nutritional values - Calories

Since real raw sauerkraut is not pasteurized, it not only contains plenty of lactic acid, but also the living lactic acid bacteria themselves.

Sauerkraut has a very low energy density of 21 kcal/100g, is low in fat and protein, contains only a few carbohydrates and a lot of fiber. Sauerkraut is also a good source of vitamins and minerals. ⁵

It should be noted that the salt content in sauerkraut is very high at 902 mg/100g due to the manufacturing process. As a result, sauerkraut also contains a lot of sodium (355 mg/100g). ^5,6

Vitamin K is well represented in raw sauerkraut with 25 µg/100g; ^5,6 it contains a similar amount of this fat-soluble vitamin as peas or shimeji mushrooms . Green vegetables, herbs and salad in particular contain a lot of vitamin K: fresh parsley has 1640 µg/100g and chard 830 µg/100g. ⁷ It plays an important role in the blood coagulation system and in bone metabolism.

With 100 g of raw sauerkraut you can cover 25% of your daily requirement of vitamin C - that's about a small portion. A much better source of vitamin C is, for example, sweet peppers (184 mg/100g). ⁷

You can find all the ingredients of sauerkraut, the coverage of the daily requirement and comparison values with other ingredients in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.

Health effects

Is raw sauerkraut healthy? Sauerkraut contains isothiocyanate. Epidemiological studies have shown that the consumption of isothiocyanates reduces the incidence of breast, lung and colon cancer. 53 to 150 μmol of isothiocyanate is said to be sufficient to produce this anti-cancer effect . This means that a few portions of sauerkraut per week could trigger this positive effect. ¹⁶

During fermentation, bacteria process carbohydrates and proteins into biologically active metabolites, including short-chain fatty acids (SCFAs) and biogenic amines. SCFAs mediate several beneficial activities in the gastrointestinal tract: intestinal motility and the integrity of the intestinal barrier benefit from them. In addition, they have antioxidant and anti-inflammatory effects . Biogenic amines and natural polyamines, such as putrescine and putrescine-derived spermine and spermidine, are often present in fermented foods as a result of bacterial decarboxylation of free amino acids and play a role in cell proliferation and differentiation. Natural polyamines influence apoptosis (controlled cell death), proliferation rate (cell growth) and cellular differentiation - important processes for the health of the intestinal mucosa.

Eating fermented foods has a significant positive effect on the barrier function of the intestine . The intestinal wall is designed to protect us from bacteria, endotoxins, antigens in food and similar substances penetrating the intestinal wall and causing inflammation. If the intestinal wall is permeable (leaky gut syndrome), this leads to chronic systemic inflammation. Researchers have observed this condition in patients with inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), diabetes, obesity and other chronic diseases. Diet appears to be one of the most important factors affecting the integrity of the intestinal barrier. Several studies have investigated the role of microbial metabolites from food in regulating intestinal permeability. There is some evidence that lactic acid and other organic acids contained in fermented products can positively affect the integrity of the intestinal barrier and thus reduce inflammation. ¹⁷

In addition to the beneficial ingredients contained in raw sauerkraut, the various living lactic acid bacteria are particularly healthy for us. Around 45-72% of the bacteria manage to survive in our digestive tract and can do their good work there. ^10,11 Those bacteria that survive the harsh gastrointestinal tract colonize the small and large intestines of the host. This has a positive effect on the microbial ecosystem of the intestine, stimulates the immune system, reduces the risk of bacterial or viral diarrhea and lowers cholesterol levels. Researchers also suspect that probiotics produce antimicrobial substances that prevent pathogens from adhering to the intestine. ¹⁸

There is scientific evidence that a healthy gut microbiome or the consumption of probiotics, such as those found in raw sauerkraut, could be linked to a healthy psyche . The few studies on this relate to depression and anxiety disorders. ^22,23

Secondary plant substances

Many of the health effects of raw sauerkraut can be attributed to the secondary plant substances it contains. Our article on secondary plant substances provides an overview of the classification of substance groups, their occurrence in foods and possible effects on humans. Raw sauerkraut contains the following secondary plant substances, among others: ¹⁹

• Alkaloids: indole-3-carbinol, indole-3-acetonitrile, 3,3′-diindolylmethane

• Organic sulphur-containing compounds: glucosinolates and their degradation products; isothiocyanates, nitriles

• Other organic compounds: Ascorbigen

However, it should be noted that the composition of the secondary plant substances in raw sauerkraut can vary depending on the unprocessed cabbage (harvest time, variety, growing conditions) and preparation. Therefore, quantities are only of limited use and should only be understood roughly.

Dangers - Intolerances - Side effects

Certain substances that are problematic for health can occur in sauerkraut: biogenic amines, nitrites and pathogens . Histamines, putrescines and cadaverines are the most common biogenic amines in fermented vegetables. Poor hygiene or reusing the brine can lead to an increased level of biogenic amines. The (good) lactic acid bacteria can also produce biogenic amines, but below the toxic threshold. The recipe can also make a big difference. For example, fish sauce increases the likelihood of biogenic amines being produced; while onions lead to fewer. ²⁰ In the case of excessive consumption or general intolerance, symptoms such as nausea, difficulty breathing, hot flushes, sweating, palpitations, headaches, rashes, burning in the mouth and hypotension or hypertension can occur. ^21,24

Nitrites can form nitrosamines, which can have a carcinogenic effect in the digestive tract. The formation of nitrites is also linked to the prevailing microbiome. Garlic appears to promote the growth of good bacteria. Bioactive additives, such as polyphenols from apple peel or the microelement selenium, can help keep the formation of nitrites in check. Certain lactic acid bacteria can also break down nitrite themselves. ²⁰

Measures to avoid these substances are: hygiene, strict exclusion of oxygen, temperature between 15 and 24 °C, fresh high-quality ingredients, starter cultures and the right salt concentration.

Folk medicine - natural healing

Sauerkraut is said to help to get the sensitive intestinal flora going again after antibiotic therapy.

Ecological footprint - animal welfare

The ecological footprint of white cabbage is generally small. A study by Greenpeace in collaboration with other cooperation partners calculated the CO ₂ footprint of sauerkraut and came up with 0.5 kg CO ₂ eq/kg. In relation to the macronutrients it contains, however, sauerkraut performs only slightly better than average foods and therefore does not contribute significantly to a climate-friendly diet. ²⁵

Based on publicly available data, Carboncloud calculated a theoretical CO ₂ footprint of 1.66 kg CO ₂ eq/kg sauerkraut. This discrepancy shows that the ecological footprint can vary depending on the method and data available. ²⁶

Factors such as the origin of the cabbage, farming methods (organic vs. conventional), processing methods and packaging significantly influence the footprint. Therefore, it is understandable that there can be strong fluctuations in the ecological footprint of sauerkraut.

Unfortunately, we could not find any data on the water footprint of sauerkraut. However, this is an important indicator for the overall assessment of ecological sustainability.

For detailed explanations of various sustainability indicators (such as ecological footprint, _CO2 footprint, water footprint), see our article: What does the ecological footprint mean?

Worldwide occurrence

Sauerkraut is particularly widespread in the USA and Europe. Fermented foods in general have always been an important source of food around the world. The Asian equivalent of sauerkraut is kimchi made from Chinese cabbage . Its consumption can be traced back to 2000 years before Christ. The positive effects of sauerkraut on health were recognized early on. In 400 BC, Hippocrates recommended eating sauerkraut to combat obesity, and the Romans consumed it to prevent intestinal infections. In the 18th century, Captain James Cook discovered that sauerkraut stored in wooden barrels prevented scurvy (extreme vitamin C deficiency) in sailors and from then on ate it on his long voyages.

The industrial production of sauerkraut began in 1830. ¹⁵

Industrial production

In the factory, the cleaned and chopped cabbage is placed in the fermentation vat. Two to three percent salt is added, evenly distributed. Covered with a heavy lid, the cabbage ferments at below 15.5 °C for at least a month. Fermentation is complete when the pH of the sauerkraut has dropped to around 3.5 to 4 and the titratable acidity (expressed as lactic acid) has reached around 1.5%. The sauerkraut has now achieved its typical acidity, taste and texture.

Large-scale sauerkraut producers use starter cultures, but on a smaller scale they rely on what is known as spontaneous fermentation. Lactic acid bacteria on the fresh vegetables and in the environment, such as Weisella spp., Leuconostoc mesenteroides, Levillactobacillus brevis, Lactiplantibacillus plantarum, and Pediococcus pentosaceus, are involved in the fermentation. ¹⁷

The fermentation of sauerkraut is a complex microbiological process. The traditional process of spontaneous fermentation of cabbage takes place in four steps:

1. Fermentation begins as soon as the tightly compressed herb is in the container. The number of aerobic bacteria such as Pseudomonas, Flavobacteria and Acinetobacter immediately decreases. Facultative anaerobic bacteria multiply in the first two to three days. The resulting acids (lactic, acetic, formic and succinic acid) cause the pH value to decrease.

2. The lack of oxygen, the salt and the acidic environment favour the growth of certain lactic acid bacteria, which soon become the predominant bacteria. Leuconostoc mesenteroides usually initiates the fermentation. Under ideal conditions, this bacterium quickly reaches a high density, producing lactic acid and acetic acid. It is a heterofermentative lactic acid bacterium, it produces CO ₂ and thereby displaces oxygen, which has a positive effect on the vitamin C content and colour of the cabbage. Another bacterium in this stage is Lc. fallax . Gradually, more and more Lactobacillus brevis are present. Depending on the temperature, these two stages are completed within 3-6 days. During this time, the lactic acid content increases to 1%.

3. In the third step, another change in the bacterial culture can be observed: homofermentative bacteria of the genus Lactobacillus are now the predominant organisms. The lactic acid bacteria in this section convert most of the carbohydrates (glucose, fructose and sucrose) into organic acids, mainly lactic acid, and the content increases to 1.5 to 2%. In Europe, the herb is considered ready at around 3.8-4.1%.

4. Only fresh, unpasteurized sauerkraut goes through the very last step: Lb. brevis and other heterofermentative bacteria that can process pentose dominate this section and further reduce the pH to 3.4. ¹²

Further information

Fermented foods and beverages make up an estimated 1⁄3 of all our food. ¹⁷

The vitamin C content of cabbage decreases during fermentation. This is partly because ascorbic acid is very susceptible to chemical and enzymatic oxidation - which is why it is an excellent antioxidant. The heavy chopping of cabbage, and to a lesser extent storage, triggers these processes. ⁸ Vitamin C is also very sensitive to heat. Interestingly, some of the vitamin is converted to ascorbigen during fermentation. Ascorbigen is converted back into vitamin C when cooked. ¹ The warmer the temperature, the faster the chemical processes take place. Therefore, vitamin C is lost more quickly during cooking .

Another issue related to sauerkraut is vitamin B₁₂ . Unfortunately, there is very little of it in sauerkraut. More B₁₂ is found in sea buckthorn or fermented parsley juice. Nevertheless, plant or fermented sources do not seem to contain enough B₁₂ to cover the requirement. Since we use this vitamin very slowly, a deficiency can only become apparent after years. ^1,13

The widespread assumption that the lactic acid bacteria used to make sauerkraut cannot tolerate iodized salt does not seem to be true, according to a 2018 study. ⁹

Alternative names

In English, the fermented cabbage is also called 'sauerkraut'. Raw sauerkraut is also called fresh cabbage.