Fully fermented sauerkraut can be canned in a boiling-water bath. The fermentation step is what makes that possible: lactic acid drops the pH well below 4.6, so the kraut is treated as a high-acid food. Plain cabbage cannot be canned the same way. It is a low-acid vegetable, and there is no tested water-bath or pressure-canning process for unfermented cabbage.
Canning is not required. Refrigerated kraut keeps for months. Freezing works too. Canning is the option when you want pantry storage and do not need live cultures. Heat kills the probiotics. What remains is still acid, flavorful cabbage that is useful in cooked dishes and lasts on the shelf.
Why fermented sauerkraut is safe to water-bath can
Clostridium botulinum cannot grow or make toxin below pH 4.6. Properly fermented sauerkraut typically finishes around pH 3.1 to 3.7. That acidity is the safety barrier. The water-bath process then kills yeasts, molds, and spoilage organisms so the sealed jar stays stable at room temperature.
Pressure canning is not recommended. There is no tested pressure process for sauerkraut, it is unnecessary for a high-acid food, and the extra heat usually turns the cabbage soft and dull. A pressure canner can be used as a water-bath canner if the jars are fully covered with water and the lid is left vented—but do not run it under pressure. Electric multi-cookers are not a substitute for either method.
Do not water-bath raw, unsalted, or only briefly brined cabbage and call it sauerkraut. The canning times assume a finished ferment.
When canning is worth it — and when it is not
Canning makes sense if you:
- Made a large batch and cannot keep it all cold
- Want shelf-stable jars for cooked meals (pork and kraut, soups, casseroles)
- Need food that will sit in a pantry or emergency store
Skip canning if you:
- Want live lactic-acid bacteria
- Only made a quart or two (the refrigerator is simpler)
- Care most about crunch and sharp, fresh acidity
Heat above about 115°F / 46°C kills the live cultures. A water bath is far hotter than that, so canned sauerkraut is pasteurized. Fiber, organic acids, and much of the flavor remain; the probiotic benefit does not. If gut bacteria are the point, refrigerate or freeze instead. Extension sources list refrigeration for several months and freezing for about 8 to 12 months.
A practical split used by many home preservers: keep some in the fridge for raw use, can the rest for cooking.
What must be true before you fill a jar
The kraut has to be fully fermented
USDA guidance for quality: at 70–75°F, fermentation usually finishes in 3 to 4 weeks; at 60–65°F it may take 5 to 6 weeks. Below 60°F it may stall. Above 75°F it often goes soft.
“Done” means bubbling has largely stopped, the cabbage looks translucent rather than raw-white, and the flavor is sour enough that you would eat it as sauerkraut. Do not can a week-old batch that still tastes like salted cabbage.
Salt and cabbage have to match a tested ratio
The research-tested home recipe is 3 tablespoons canning or pickling salt per 5 pounds of shredded cabbage (¾ cup salt for 25 pounds, which yields about 9 quarts). That is roughly 2–2.5% salt by weight. Too little salt softens the kraut and weakens the ferment. Too much delays fermentation and can encourage pink yeast growth. Do not swap in iodized table salt for the ferment; anti-caking agents and iodine can cloud brine and affect color.
Do not can a spoiled ferment
Discard the batch if you see fuzzy mold (any color), slimy texture, a rotten or cheesy smell, or pink discoloration from yeast plus slime. A thin white film on the surface during fermentation is often kahm yeast and can be skimmed if the kraut underneath smells clean and sour—but do not can a batch you would not eat. Pink from red cabbage pigment is different from pink yeast growth.
Stick to plain fermented cabbage for canning
The tested canning process is for sauerkraut made from cabbage and salt. Adding extra vegetables, meat, or untested spice blends before processing changes density and acidity. Whole spices used during fermentation are a gray area; ground spices and extra produce are not covered by the USDA table. If you want caraway or apple in the jar, add them when you cook the opened kraut.
Hot pack vs raw pack
Both methods are official. They use the same headspace and the same canner. They do not use the same time.
| Method | What you do | Tradeoff |
|---|---|---|
| Hot pack | Heat kraut and its juice slowly to a boil, then pack | Better jar fill, less floating, usually better color; slightly softer texture |
| Raw pack | Pack cold fermented kraut and cover with its juice | Faster prep; more siphoning, more floating, more chance of darkening at the top |
Leave ½ inch headspace either way. Pack firmly so brine covers the solids. If the ferment did not make enough juice, cover with a boiled-and-cooled brine of 1½ tablespoons canning salt per quart of water. Do not top off with plain water.
Preheat the canner water to about 180°F for hot pack and about 140°F for raw pack so the jars do not crack and so you do not stall the boil.
How to can sauerkraut, step by step
- Inspect jars for chips. Wash jars, lids, and bands. Keep jars hot if you are hot packing.
- Skim any surface film from the ferment. Taste the kraut. Only proceed if it is clean, sour, and fully fermented.
- Hot pack: Put kraut and juice in a large pot. Bring slowly to a boil, stirring so it does not scorch. Remove from heat. Raw pack: skip the heating.
- Pack firmly into pint or quart canning jars. Cover with hot juice (hot pack) or fermentation juice (raw pack). Leave ½ inch headspace.
- Remove air bubbles. Recheck headspace. Wipe rims. Apply two-piece lids fingertip-tight.
- Load jars into the water-bath canner. Water must cover the lids by 1 to 2 inches.
- Bring to a full rolling boil, then start the timer. Maintain a boil for the full time in the table below.
- When time is up, turn off the heat, remove the canner lid, and wait 5 minutes before lifting jars out.
- Cool 12–24 hours, undisturbed, on a towel. Do not retighten bands.
- Check seals. Remove bands, wipe jars, label with pack style and date. Refrigerate any unsealed jar and use it soon, or reprocess within 24 hours with a new lid.
Start the timer only after the water returns to a full boil. Timing from the moment jars go in under-processes the food.
Water-bath processing times for sauerkraut
These times are from the National Center for Home Food Preservation / USDA Complete Guide to Home Canning. Adjust for your elevation. Water boils at a lower temperature as altitude rises, so time increases.
| Style of pack | Jar size | 0–1,000 ft | 1,001–3,000 ft | 3,001–6,000 ft | Above 6,000 ft |
|---|---|---|---|---|---|
| Hot | Pints | 10 min | 15 min | 15 min | 20 min |
| Hot | Quarts | 15 min | 20 min | 20 min | 25 min |
| Raw | Pints | 20 min | 25 min | 30 min | 35 min |
| Raw | Quarts | 25 min | 30 min | 35 min | 40 min |
A steam canner may be used only if it is a tested atmospheric steam canner and you follow that manufacturer’s and current USDA guidance for high-acid foods. Do not invent a shorter time.
Storage, quality, and what to expect from a canned jar
Store sealed jars in a cool, dark, dry place. Quality is best within about 12–18 months; the food can remain safe longer if the seal stays intact and the jar looks and smells normal when opened.
Canned sauerkraut is usually a bit softer and a little less sharp than fridge kraut. Hot pack tends to look more even in the jar. Raw pack may show some floating shreds or a darker layer at the top from trapped air. That is a quality issue, not automatic spoilage—if the seal is good and there is no off odor, gas, or slime.
Before eating any home-canned food, check the lid, look at the contents, and smell. Do not taste from a bulging lid, a leaking jar, spurting liquid, or food that smells wrong. “When in doubt, throw it out” applies here as it does to every canned product.
Once opened, refrigerate and use within about a week to a few weeks, the same as opened commercial shelf-stable kraut.
Problems that show up after canning
Mushy kraut. Fermented too warm, under-salted, shredded too fine, boiled hard before packing, pressure-canned, or processed far beyond the table. Soft kraut can still be safe if the ferment was sound and the jar sealed; it is a quality loss.
Darkening. Iodized salt, light during storage, high fermentation temperature, or air left in a raw-pack jar. Store in the dark.
Siphoning (liquid loss). Jars packed too full, bands overtightened, canner water fluctuating, or raw pack. As long as the seal holds and solids stay covered or only slightly exposed, the jar is usually still usable. Uncovered food at the top may darken.
Unsealed lids. Chipped rims, food on the rim, old lids, or cooling the jars in a draft. Refrigerate or reprocess.
Too salty in the finished jar. Salt does not cook out. Rinse a serving under cold water before you eat it, or use that jar in a soup or braise where liquid balances the salt. Do not reduce salt in the next ferment below the tested ratio if you plan to can.
You canned cabbage that never fully soured. That is the serious error. The process times assume finished acidity. If you realize the batch was under-fermented, do not leave those jars on the shelf. Treat them as untested low-acid food: refrigerate and use soon, or discard.
Scaling a batch without changing the formula
The official large batch is 25 pounds of cabbage to ¾ cup salt, about 9 quarts. The ratio scales cleanly:
- 5 lb cabbage + 3 Tbsp salt ≈ 2 quarts
- About 2 medium heads ≈ 1 quart of finished kraut, depending on how tightly you pack and how much moisture the cabbage holds
Weigh shredded cabbage. Volume of whole heads varies too much to guess salt.
If juice does not cover the cabbage during fermentation, add the weak brine listed earlier. Keep the cabbage submerged. That is a fermentation rule, not a canning shortcut.
Frequently asked questions
Can I can sauerkraut I already moved to the refrigerator? Yes, if it still smells and looks like good kraut—no mold, no slime, no off odor. Pack and process the same way.
Can I use the low-temperature pasteurization method used for some pickles? No tested sauerkraut recipe authorizes that 180–185°F water treatment. Extension answers that have looked at the question say to stick to the boiling-water table or keep the kraut refrigerated.
Can I can red cabbage sauerkraut? Color is not the safety issue. The same salt ratio, full ferment, and process times apply. Expect a different color in the jar.
Should I boil canned sauerkraut before eating it? The CDC boiling advice for home-canned food is aimed at low-acid vegetables and meats. Sauerkraut processed by the tested water-bath method is a high-acid food. Still discard any jar with a failed seal or spoilage signs, and do not taste from a suspicious jar.
Is store-bought refrigerated kraut the same as home-canned kraut? No. Refrigerated commercial kraut is often unpasteurized. Shelf-stable supermarket cans and jars are pasteurized, like yours will be after a water bath.
Do I need a crock? No. Food-grade plastic, glass, or a crock all work for the ferment. What matters for canning is the finished product, not the vessel.
Canning sauerkraut is a two-stage job: a correct ferment, then a tested water-bath process. Skip either stage and you either lose safety or lose quality. If you want live kraut, leave it in the fridge. If you want cabbage that sits on a shelf until you need it for dinner, ferment it fully, pack it by the book, and use the times for your altitude.