Unpasteurized sauerkraut is raw, salt-fermented cabbage that has never been heated, so the lactic acid bacteria that did the fermenting are still alive when you eat it. That living culture is exactly what makes it a probiotic food — and exactly what pasteurized, canned kraut has lost.
What unpasteurized sauerkraut actually is
Sauerkraut is nothing more than cabbage and salt. Shredded cabbage is salted, packed tight, and left to ferment under its own brine. Wild lactic acid bacteria already present on the leaves — mostly Leuconostoc and Lactobacillus species — convert the cabbage sugars into lactic acid. That acid is what turns fresh cabbage sour, keeps it safe, and gives kraut its clean tang.
Unpasteurized simply means that after fermentation the kraut was packed cold and never cooked. Those billions of bacteria are still living in the jar. This is the traditional form of sauerkraut, and the only form that delivers meaningful live probiotics to your gut.
Why 'raw' matters for probiotics
The whole point of eating fermented cabbage for gut health is the live bacteria. Heat is their enemy. Pasteurization — heating the kraut to roughly 70°C or higher to make it shelf-stable — kills the cultures outright, and so does any real cooking.
Once the bacteria are dead, you still have a fermented food with fibre, vitamin C, vitamin K, and the tangy flavour and organic acids from fermentation — but it is no longer probiotic. If your goal is a diverse gut microbiome, raw is the only version that counts.
Raw vs. pasteurized: how to tell them apart
The two look almost identical in the jar, so read the clues rather than the picture on the label.
Where to find raw sauerkraut
Always start in the refrigerated section — near the tofu, kimchi, and chilled pickles — not the canned-goods or condiment aisle. Bagged fresh kraut and small-batch jars are usually raw, while the classic cans and warm-shelf jars are pasteurized.
Widely available raw brands include Bubbies, Wildbrine, Cleveland Kitchen, and Farmhouse Culture, plus countless local and farmers-market makers. When in doubt, flip the jar over: the ingredient list on real raw kraut is short — cabbage, salt, and maybe caraway, dill, or juniper. Nothing else needs to be there.
What live sauerkraut does for you
Treat kraut as a daily condiment rather than a cure. A forkful or two alongside a meal is plenty to start, and consistency matters more than quantity.
Free Fermentation Salt Reference Card (printable PDF)
A printable PDF companion for the brine & pickling calculators and guides.
Keeping the cultures alive
Buying raw kraut is only half the job — it’s easy to accidentally kill the very bacteria you paid for.
Watch for
- Never boil or simmer raw kraut — heat above ~46°C kills the probiotics
- Cooking it into sausages or stews destroys the live cultures
- Leaving the jar out warm for long stretches degrades the bacteria
- Letting the cabbage sit above the brine invites mould and dries out the culture
To keep the benefit, eat raw kraut cold: pile it on after cooking, fold it into a finished bowl, or serve it on the side. If you love warm kraut with dinner, cook a pasteurized batch for the plate and keep a jar of raw for topping.
Storing your kraut
Kept cold and submerged in its own brine, raw sauerkraut lasts for months — often four to six or longer — because the acidity preserves it. It keeps slowly fermenting in the fridge, so it grows softer and more sour over time; that’s normal, not spoilage.
Always press the cabbage back under the brine after serving and use a clean utensil each time. Discard a batch only if you see fuzzy mould, smell something genuinely rotten or yeasty-off, or the texture turns to slime — sour and tangy is exactly right.
Making your own raw sauerkraut
Homemade kraut is the cheapest, freshest live culture you can get, and it needs almost nothing.
- 1Weigh cabbage and salt Shred cabbage and weigh it. Use about 2% of that weight in salt — for lacto-fermented cabbage the sweet spot is roughly 2 to 2.5%. Run the numbers through the brine calculator to get it exact.
- 2Salt and massage Toss the shredded cabbage with the salt and massage for 5 to 10 minutes until it wilts and releases enough liquid to form its own brine.
- 3Pack it tight Press the cabbage firmly into a clean jar or crock so the brine rises above the shreds. Every piece must stay submerged — use a weight or a cabbage leaf on top.
- 4Ferment at room temperature Keep it around 18–22°C, away from direct sun. It will bubble within a few days; taste from about day 5. Most kraut is ready in 1 to 4 weeks depending on temperature and how sour you like it.
- 5Refrigerate raw When it tastes right, cap it and move it to the fridge. Do not heat or can it — cold storage keeps it raw, safe, and full of live cultures.
Is it safe?
Properly fermented sauerkraut is one of the safest foods you can make. As the bacteria produce lactic acid, the pH drops below 4.6 — an acidity level that stops harmful bacteria from taking hold. That’s why kraut has been preserved and eaten safely for centuries without refrigeration.
Get the salt right, keep everything under the brine, and trust your senses: good kraut smells sour and clean and stays crisp. If you’re pregnant or immunocompromised, check with your doctor before eating raw fermented foods, and if you’re new to them, start with a small spoonful and build up. For a full breakdown of the risks and how to lower them, see our guide on is sauerkraut safe during pregnancy. More common questions are answered in our sauerkraut FAQ.
