Canning Sauerkraut and Fermented Pickles: Times by Jar Size and Altitude

Two home ferments have a tested, published canning process: fully fermented sauerkraut and fermented dill pickles. Both go in a boiling-water canner, for 10 to 40 minutes depending on how you pack the jars, their size and how high
above sea level you live. The heat that makes the jars shelf-stable also kills the lactic acid bacteria, so canned kraut keeps in the
cupboard (best used within a year) but is no longer a live food. If you want it live, keep it in the fridge instead.

Which Ferments Have a Canning Process

The US National Center for Home Food Preservation (NCHFP), which puts the USDA’s home-canning guidance online, gives boiling-water
canning times for its sauerkraut and its fermented dill pickles. Those are the only two
fermented vegetables in its fermenting recipes with a canning step. NCHFP’s rule for pickled products is to use “only recipes with
tested proportions of ingredients” (NCHFP), and a canning time only holds for the food it was worked out on.

For anything else, the fridge is the safe store. Nebraska Extension puts it plainly: only ferments with a recipe developed for a
boiling-water canner come out shelf-stable, and “currently, there is no home canning recommendation for kimchi” (Nebraska Extension).
A University of Wisconsin–Madison Extension kimchi recipe likewise says “this product can not be safely canned”
(UW–Madison Extension); our kimchi shelf-life guide covers how long it keeps cold. The same
goes for fermented hot sauce, fermented garlic and mixed-vegetable jars: none has a tested home canning
process, so don’t improvise one. (NCHFP’s canned hot sauces are vinegar sauces, not ferments.)

Before You Can: Fully Fermented, Made by the Recipe

The times below were set for kraut and pickles that have finished fermenting. NCHFP’s sauerkraut takes about 3 to 4 weeks at
70–75°F (21–24°C), or 5 to 6 weeks at 60–65°F (16–18°C); its dill pickles take about 3 to 4 weeks at 70–75°F
(NCHFP sauerkraut; NCHFP dill pickles). With the brine-bag method, kraut is done when the
bubbling stops. A half-sour pickle pulled after a week, or kraut you moved to the fridge after a week or two because you liked it
crunchy, is not the product these times were worked out for; keep those in the fridge.

Can only a batch that looks and smells clean and sour. NCHFP says to discard pickles that “become soft, slimy, or develop a
disagreeable odor” (NCHFP dill pickles), and Oregon State University Extension says slimy kraut “indicates
spoilage; discard kraut” (Oregon State). Canning won’t rescue a batch that has gone wrong, and one with mould spread over
it goes in the bin, not the canner.

Make the ferment the way NCHFP does. For kraut that means shredded cabbage and salt only: about 20–25 g of salt per 1 kg of cabbage,
or 2–2.5% of its weight (NCHFP’s 3 tablespoons per 5 pounds), as in our sauerkraut recipe. Kraut with carrot,
garlic, onion, beetroot or other vegetables mixed in has no tested canning time, so keep it in the fridge. For pickles, use the salt,
vinegar and water brine in our fermented dill pickle recipe (NCHFP: 1/2 cup of salt, 1/4 cup of 5% vinegar and
8 cups of water per gallon jar).

Canning doesn’t make a low-salt ferment safe. NCHFP says salt in sauerkraut and brined pickles “is vital to safety and texture” and
warns: “Do not attempt to make sauerkraut or fermented pickles by cutting back on the salt required”
(NCHFP). Ohio State University Extension says the same of salt substitutes: the product “will not ferment
correctly” (Ohio State).

Sauerkraut: Hot Pack or Raw Pack

NCHFP gives two ways to fill the jars (NCHFP sauerkraut):

• Hot pack: bring the kraut and its juice slowly to a boil in a large pan, stirring often. Take it off the heat and fill the jars
  fairly firmly with kraut and juice, leaving 1/2 inch (about 1.25 cm) of headspace.
• Raw pack: fill the jars firmly with cold kraut and cover it with its juice, leaving the same 1/2 inch of headspace.

Raw-packed jars start cold, so they need longer in the canner. Process times in a boiling-water canner, in minutes:

Source: NCHFP, adapted from the USDA Complete Guide to Home Canning (2015). Half-pint jars take the pint time
and 1 1/2-pint jars the quart time (NCHFP).

Fermented Dill Pickles: Boiling Water or the 180°F Bath

To can fully fermented pickles, pour the brine into a pan, heat it slowly to a boil and simmer it for 5 minutes. You can filter it
through paper coffee filters to clear it. Fill the jars with pickles and hot brine, leaving 1/2 inch of headspace
(NCHFP dill pickles). Then use one of two treatments.

Minutes in a boiling-water canner; note the pickle table’s middle band runs all the way from 1,001 to 6,000 ft, unlike the kraut
table (NCHFP dill pickles; Ohio State’s fact sheet gives the same times up to 6,000 ft).

The second option is low-temperature pasteurization, which NCHFP says gives a better texture “but must be carefully managed to
avoid possible spoilage” (NCHFP):

1. Set the filled jars in a canner half full of warm water at 120–140°F (49–60°C).
2. Add hot water until it’s 1 inch (2.5 cm) above the jars.
3. Heat the water to 180–185°F (82–85°C) and hold it there for 30 minutes, checking with a thermometer. It must stay at least 180°F
   (82°C) for the whole 30 minutes; above 185°F (85°C) the pickles soften.

NCHFP gives this option for the pickles only (“Use only when recipe indicates”), so sauerkraut gets the boiling-water times above.

Running the Boiling-Water Canner

These steps follow NCHFP’s directions for boiling-water canners (NCHFP) and for cooling and checking
jars (NCHFP).

1. Use standard canning jars with new self-sealing lids. All the times on this page are 10 minutes or more, so the jars need to be
   clean and hot but not sterilised first (NCHFP).
2. Put the rack in the canner, fill it about halfway and preheat the water: to 180°F (82°C) for hot-packed kraut, 140°F (60°C) for
   raw-packed kraut and for pickles, which NCHFP processes as a raw pack.
3. Lower the filled, lidded jars in upright, then add hot water until it’s at least 1 inch (2.5 cm) above the jar tops; for times over
   30 minutes, at least 2 inches (5 cm).
4. Cover the canner and heat on high until the water boils vigorously. Start the timer only then.
5. Keep it at a full boil for the whole time. If the boil stops, bring it back to a vigorous boil and start the timing again from
   zero.
6. When the time is up, turn off the heat, take off the lid and wait 5 minutes. Lift the jars out onto a towel, 1 inch apart, and leave
   them undisturbed for 12 to 24 hours. Don’t tighten the lids.
7. Check each seal: the lid should be curved down in the centre, not spring back when pressed, and ring when tapped with a spoon.

The altitude bands exist because water boils cooler the higher you are: 212°F (100°C) at sea level, 201°F (94°C) at 6,000 ft and
194°F (90°C) at 10,000 ft (NCHFP). The extra minutes make up for the lower temperature. Shortcuts don’t: NCHFP
advises against open-kettle canning (hot food, lid, no processing) and against processing jars in an oven, microwave or dishwasher,
because these “do not prevent all risks of spoilage” (NCHFP).

What Canning Changes: Live Cultures, Texture, Shelf Life

Processing in a boiling-water canner prevents spoilage by yeasts, moulds and enzymes (NCHFP). The lactic
acid bacteria that soured the kraut don’t survive it either, which is why shelf-stable sauerkraut has no live cultures (see
what heat does to the bacteria in fermented foods). Unheated home ferments are a different product: in 75
homemade fermented vegetables collected from households in France, lactic acid bacteria were the main live bacteria, and the youngest
samples (under 100 days) most often had the highest numbers (Thierry et al., 2023).

So the choice is a trade. Fully fermented kraut “may be kept tightly covered in the refrigerator for several months”
(NCHFP), and fermented pickles about 4 to 6 months in the fridge if you remove any surface scum or mould
(NCHFP). Canned jars keep in a cool, dark, dry place, best between 50 and 70°F (10–21°C) and never above 95°F (35°C), so not near
the stove, a furnace or in a hot attic; NCHFP suggests canning no more than you’ll use within a year (NCHFP).
Store-bought shelf-stable kraut is a different case, covered in how long sauerkraut lasts, opened and unopened.

Heat also softens: NCHFP offers the 180°F bath for pickles because
it gives a better texture, and warns that water above 185°F softens them (NCHFP).

A Jar That Didn’t Seal, or Looks Wrong Later

If a lid hasn’t sealed, the simplest fix is to put that jar in the fridge and eat it within several days, or freeze it once you’ve spooned out enough to leave about 1 inch (2.5 cm) of headspace
(NCHFP). NCHFP doesn’t recommend reprocessing because it costs quality. If you do reprocess kraut, do it within
24 hours: empty the jar into a pot, bring it to a boil, fill a clean jar, put on a new lid and process it for the hot-pack time. Pickles
have no hot-pack process, so put an unsealed pickle jar in the fridge (NCHFP). Once sealed, take the screw bands off, wash and dry the jars, label and
date them; stored without bands, a lid that has come loose is easier to spot (NCHFP).

Before opening any jar, check it. A bulging or loose lid, streaks of dried food running down from the top of the jar, rising
bubbles, liquid that spurts when you open it, an unnatural smell or colour, or cotton-like mould on the food or under the lid are signs of
spoilage (NCHFP). Don’t taste it: close it in a heavy bin bag and throw it away.