Fermenting vegetables is, in truth, a very simple process. This tutorial is intended to demystify the process and give some pointers. For this, as you’ll see from the pictures, I’ve used a knob of daikon radish and some celery, as well as pink Himalayan salt from Costco. Along with water and a jar, that’s all you need to perform lactic acid fermentation and get nice, sour, pickle-y fermented vegetables. Mason jars are perfect for this, as are repurposed jars for things like spaghetti sauce, jelly or jam, or pickles.
This piece covers the three things I consider most important to the process: preparing your vegetables, keeping them submerged, and mixing the brine in which they will ferment.
This how-to is mostly geared to firm vegetables like celery, carrots, radishes, and so on. Once you’ve gathered your materials, select your vegetables and process them however you’d like. You can slice them into coins, matchsticks, or chunks. You can peel them or just rinse them off.
Once your vegetables are cut the way you like – and remember, assuming they fit well into the jar you’re using, there’s no wrong way to do this – put them into your jar.
Keep Everything Submerged
This is probably the most important rule when fermenting vegetables. The risk when solids float, including spices you may put into the batch, is that mold can form at the surface. People have differing opinions and risk tolerances when it comes to mold, but I think it’s fair to say that most of us take some steps to prevent it in the first place. Full submersion of everything is the single best step to achieve that.
For years, I used various jury-rigged approaches, including putting a smaller jar into the mouth of the larger jar, like this:
Another method that’s easy and puts leftover veggie bits to use is to press them into the jar over the vegetables you’re fermenting, but beneath the shoulders of the jar:
My favorite approach is the use of Pickle Pebbles (affiliate link), a product sold by a company called Masontops. These are purpose-built glass weights that are nice and thick and let you use the jar’s lid, unlike the jar-in-jar method. I love mine, but as with everything fermentation-related, there’s no need to spend money if you don’t want to.
Because I had room in the jar, I ended up using both the crammed-in-celery and the Pickle Pebble methods.
Those veggie sticks aren’t going anywhere. Now let’s talk about brine.
Mixing Brine for Fermenting Vegetables
Vegetables ferment in a saltwater brine. You can get very creative with this, adding herbs and spices and whatever else you like, but the basic idea is that the salty brine creates an ideal environment for beneficial fermentation organisms living on the vegetables themselves to bloom, while discouraging competing organisms. In this environment, a succession of organisms will develop that gradually acidify the brine with lactic acid while they feed on various components, usually poorly digestible to us, in the vegetables. Sandor Katz calls this “pre-digestion,” and describes the microbes as unlocking nutrients that are harder for our bodies to access in a raw vegetable.
You can make this as complicated as you want, but it’s not rocket science. A heaping tablespoon of salt dissolved in a quart of water makes a perfectly acceptable brine. If you like it saltier, add more. If it’s too salty for your taste (and you can taste it to decide), water it down a bit.
If you want to get super precise with your brine concentrations, you’ll want to pick up a digital kitchen scale (aff) that gives you measurements in grams as well as ounces:
This requires some metric math, which isn’t intuitive for most Americans, but basically, your Mason jar is graded on the side, so you can easily measure out 500mL of water, or half a liter. You’ll need a bowl or large measuring cup for the final mixing, but here’s how you get a brine of about 2%:
- Put 20g of salt in your Mason jar.
- Fill Mason Jar to the 500mL line.
- Stir or (with the lid on) shake the jar until the salt is pretty well dissolved.
- Pour the salt water into a large bowl or measuring cup.
- Top off with another 500mL of water.
- Stir. This is a 2% brine.
In the metric system, the various measurements reference each other, so 20g of salt is 2% of 1000mL. The bowl is required because the Mason jar maxes out at about 900mL if you fill it to the tippy top.
Let me clarify heartily here: This level of precision is absolutely unnecessary in making fermented vegetables. But who doesn’t like to nerd out with kitchen tools?
Once your brine is mixed and your vegetables are in your jar, add the brine. In a perfect world, everything in the jar will be fully submerged and you can loosely put the cap on. If you put the cap on tightly, you’ll need to “burp” the jar once or twice a day for a week or so to prevent gas build up. Don’t make bottle bombs. Bottle bombs are bad.
If you’re using a jar-in-jar method or other irregularly-shaped improvisation, cover with a kitchen towel or something similar and use a rubber band to secure it onto the fermentation jar. This will discourage fruit flies who, no joke, are already fantasizing about the acidifying mixture you’re leaving out for them.
Put the jar aside for a week or so, at least. You can technically let this thing ferment for months, but I admit that I lack the patience for that.
It’s never a bad idea to put the jar into a bowl or baking dish in case it overflows. The early stages of fermentation result in a pretty violent release of CO2 that can easily push your brine out. If that happens, check the brine level in the jar and add more as needed to keep your veg submerged.
And that’s really it. Brine over submerged vegetables results in fermented vegetables after a week or two. The fun comes with finding different flavor mixtures, different spice combinations, and other variables to produce an end product that’s uniquely your own – as well as highly nutritious and delicious. Enjoy!