Fermentation Notes

Please be sure to also see the Fermentation Recipes page!

Notes on Fermentation
 NOFA Conference Workshop 1/25/2014
Sauerkraut & Kimchi

Updated Feb 7, 2014

Lactobacillus plantarum is the beneficial bacteria being cultivated for sauerkraut and kimchi.

Fermentation is “cooking without heat” - mix anything raw with salt and go! One exception: don't use raw potatoes for fermentation.

“Pickling” is a broad umbrella for vinegar-based pickling (simple cucumber pickles) or brine-based
pickling (using salt - such as kimchi and sauerkraut.)

When slicing cabbage you can do a fine cut or chunks – matter of preference but know that chunks will not absorb the salt as readily as a fine cut, and so getting the liquid to leach from the batch may be more difficult and water may need to be added to create the brine.

Do not use chlorinated water – it kills the beneficial bacteria you are trying to cultivate. The chlorine will evaporate from a wide mouth container left open to the air overnight.

The USDA has never reported a single case of food poisoning
via vegetable- or produce-based ferment.  However, meats especially are more tricky and you have to be very careful with them.

 Preparation, Storage and Ferment Containers
 Lead free ceramic crock (buy a lead test kit at hardware store, scratch off a little of the glaze off the bottom of the crock to test.)
Do not use metal containers or bowls unless they are 100% food-grade stainless steel.
Especially if using small vessels such as canning jars, you will need a bowl underneath it to catch the overflow.  The development of the lactic acid creates carbon dioxide that pushes the liquid out as it bubbles up and over.  This is normal, and the overflow liquid can be re-used.
Do not use a tight lid on the vessel (unless it has an airlock.)  A towel will allow gases to escape and keep critters, dust and detritus out of the jar, so it is recommended to cover the vessel with a towel fastened with a rubber band.

 Do not use salt with additives (anti-caking agents, etc.) Coarse salt is preferred to avoid potential “pitting” of the cabbage by fine salt insinuating itself into the leaf. Sea salt has minerals that will add to your ferment, kosher salt does not and is therefore not preferred.

8,000 mg. Salt = 1 Tbsp. Which is appropriate for 3# of cabbage, equaling 1-1/2 quarts Sauerkraut

You do not need as much salt as older recipes call for – they are overdoing it because they did not have refrigeration to preserve the kraut longer. If you need the batch to last a really long time (in or out of the fridge) then go ahead and use more salt but in this day and age it's generally not necessary unless you prefer really salty food.

On the other hand, you do need SOME salt – not only does it make the liquids emerge from the vegetation, it also lends strength to the pectins which keep the crisp, crunchy texture of the cabbage.

Salt substitutes include whey, probiotic capsules and seaweed. Whey makes is not vegetarian, of course, and is called a dairy ferment. In very small batches whey may help usher in the good bacteria you seek, but it may also make it mushy. None of this is necessary; it's really just an additive. Simple salt is more easily regulated (you know exactly how much of the active ingredients are going into your food when you use a measured amount of salt) and will do the same job as these other additives.

Releasing the Liquids
When making the sauerkraut or kimchi it helps to release the liquid if you mix the cabbage in the bowl well with your hands. The fresher the cabbage, the more liquid it releases. You do not need to make a brine in advance, but can create it through the use of salt and by gentle “massage” of the cabbage, by mixing and flipping it over and over in the bowl with your hands. If you are making a ferment of a low-moisture vegetable such as turnip or beet, you will need to make the brine.  

Some people pound the cabbage to release the liquids but that's usually not necessary – simple “massaging” or mixing by hand of the salted sliced cabbage in a mixing bowl should release the liquids without battering and bruising the food.  If you really can't get the liquid to release and cannot add brine for some reason, then perhaps pounding may be helpful? But to start out pounding isn't necessary - someone's mom started doing it back in the homeland and it's something some people think you're supposed to do, but most of the time it “doesn't hold water” (literally!) haha!

It takes 4-7 days for the vegetables in your vessel to "relax" and not need pushing down as much but then watch for evaporation and add more bring if needed to keep the vegetables submerged.

Active ingredients for a successful ferment are:

Light - Some people say to keep your fermenting foods away from strong light, because light destroys lactic acid bacteria. If, for some reason, you cannot avoid direct light hitting your vessel you could drape a towel around it.  However, there are mixed theories on avoiding light or not - in commercial cucumber pickle production, fermentation is done in open-top tanks that are located outside so the brine surface is exposed to sunlight to kill aerobic surface yeasts.  Light does leach out vitamin C and you get more nutritional value when you store them away from light, once the ferment has been completed.

Temperature – stable, cool. Not too warm, after the initial releasing of liquids is done. 65-75 ideal, but a little cooler is okay (just slower.)  If you can't control the temp and it's very warm, use more salt to prevent rotting - if cooler, use less.

Length of time – longer = softer / mushier

Amount of Salt – more salt slows the process.

You can add high tannin vegetation such as horseradish leaf, grape leaf, etc. to help retain crisp texture – even as a topper on the jar, if using small batch method in the canning jar. Using an outer leaf of the cabbage that you would have otherwise composted (or other type of leaf) to cover the kraut or kimchi before applying the weight is a nice line of defense against air infiltration.   It is a barrier between the cabbage underneath and the item being used to weight it down.

To re-package the finished batch for home enjoyment (if it was made in a large batch rather than already directly in the canning jar) – generally the very longest time preferred to retain crispness of sauerkraut is about 6-8 weeks in the crock, but this is a matter of taste, and it can be jarred up much sooner than that.
Michaela usually jars up kraut at 3-4 weeks, and 6 weeks to 2 months is the longest she's heard of anyone fermenting outside of refrigeration -- and those krauts are substantially softer. Under refrigeration, krauts will last for over a year, but they will soften over time.
It is a matter of the texture versus flavor (longer ferment = more flavor but loss of crispness in texture.) You're looking for the “sweet spot” between the two factors that works for your palette – for both sauerkraut and kimchi. However, for kimchi the time frame is MUCH shorter – from five days to a couple of weeks, depending on your taste.

Refrigerate the “finished” product once you've decided it is "to your taste" and have moved it from the crock or larger vessel into smaller containers.  Kimchi will stay good in the fridge for years, sauerkraut for months -- even after the jar has been opened, if it is kept well packed down in the liquid. You want to keep that anaerobic environment in play, so keep it submerged or it will begin to rot.

The brine leftover when you've finished eating a jar can be re-used for another pickling project or for salad dressing and other places you'd use vinegars as well!

A brine of salty water can be made in advance for the brining method, or don't bother and make the brine naturally from the juices of the cabbage being released by salt.

Half Sour versus Full Sour Brine
Full sour is 5% salt. It takes longer to ferment and is more sour. Recipe: 3T salt per quart is sufficient for full sour.
Half sour is 3% salt and goes more quickly, is less sour tasting.

Old-timers made 10% brine when they had little refrigeration and needed to keep it on the shelf longer (instead of the fridge) after jarring it and once it had been opened. They would see if a raw egg would float in the brine to see if it was at 10% or not.

Can use a crockpot insert as the crock fermentation vessel. There are also Harsch brand crocks that have a moat built in for a superior air barrier.

Medicinal Properties
Take a shot of brine 15 minutes before eating in order to ameliorate acid reflux.


·     Cabbage
·     Radish, onion, or many other vegetables of choice can be added
·     Spices
·     Fish sauce, if desired (for traditional kimchi)
·     Salt
·     Towel and rubberband or other snugging device (to keep insects out but allow the gases to b released)
·      Weighting device(s) – plate and rock, smaller jar, or a plastic bag filled with brine (in case it leaks it's okay), or doubled up plastic bags filled with water (leaking water in the vessel would be bad!)
·      Parchment paper, outer leaf of cabbage, or other vegetation to form a barrier between the batch and the item providing the weight on top
·      Labels (painters blue tape works well for ease of removal) / marker pen to date the jars or crock
·      Wide mouth jars and a crock – fermentation vessel must be taller than it is wide for air and gases to escape efficiently
·      Funnels for wide mouth jars
·      Bowl for overflow if making small jar batches or crock is overfull
·      Compost pails
·      Chop stick or similar for routing out the air in the fermentation vessel before applying weight (or use your finger)
·      Cutting board
·      Knives

NOFA Workshop Presenters were:

Angela Davis of Just Food NYC and the Meet-up group NYC Ferments.
Michaela Hayes of crockandjar.com - a great resource website.

Michaela Hayes
Chief Food Preservationist
Crock & Jar
Preserving the Seasons to Eat Locally Year Round
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