If you’re like me—and I know I am—then you have spent a non-zero amount of time during this pandemic feeling like your productivity is swirling down the proverbial toilet. Early in the quarantine era I decided to tackle vegetable fermenting, a thing I had long been interested in but had previously avoided out of fear that I would screw something up and poison myself.
Learning how to ferment seemed like a worthwhile way of using up stagnant energy, but I am not a scientist—what right did I have to put food in jars and try to thread the narrow needle of fermented food safety? I read some books and guides and quickly realized what I don’t like about (many) books and guides: authority. A lot of these books take a definitive stance on certain points that, in my opinion, don’t need to be so uptight, man. My experience has shown me that fermentation is as much an art as a science, unsurprisingly considering humans have employed fermentation as a preservation technique for actual millennia. If it was broadly unsafe and causing people to die in large numbers, they probably would have cut it out long ago.
If you have similar concerns or fears about fermenting your own pickles, I’m here to assure you that you’re a damn adult and you can be trusted with this process. Your only role is to create an environment in which friendly bacteria can do the real work.
Meet Lactobacillus, you’re already living together
Despite seeming like complex bacterial sorcery, fermentation is actually far easier to understand than American football. When we talk about fermenting vegetables in salt, we are talking about lacto-fermentation, so named for Lactobacillus, the friendly bacteria doing all the heavy lifting in the jar while you thousand-yard-stare your way through another Zoom meeting. Lactobacillus bacteria are hungry little pigs for the sugars in vegetables (and fruit, for that matter), which they convert into lactic acid, a natural preservative. Fermentation keeps your veg edible for the long(er) term, creates lots of new and interesting flavors, and introduces some excellent probiotics into your gut.
Where do the Lactobacillus come from? Everywhere! Your environment is filthy with them. They’re present on the vegetables themselves, and probably all over your kitchen, and even on your hands. Some types of Lactobacillus are living inside your body right now. This is why, when fermenting, you want to be clean, but not too clean, because the total eradication of bacteria is not a battle you’re going to win. Some fermentation guides are obsessive about sanitizing equipment, but I find this kind of stress just adds to my already significant flailing-anxiety burden, and murdering all the bacteria on your vegetables will make it much more challenging to get a good tasting ferment. (Also, please side-eye anyone who instructs you to sterilize anything in your home kitchen; you’re not going to do it. Sanitize, okay; sterilize, no).
Rinse and scrub vegetables under water only, wash your jars thoroughly with non-antibacterial soap, and wash your hands often. That’s all. You don’t need to climb into a biohazard suit and bleach your onions layer by layer to safely make some dang lacto-pickles.
Let’s get salty
The other reason to lower the temp on any food-borne illness concerns is that immersing vegetables in brine starts a process that eradicates bad, illness-causing bacteria in favor of good, pickle-making lacto bacteria. The bad bacteria hate salt, while Lactobacillus are cool with it. By making a brine with the correct ratio of salt to water, we create an environment in which bad bacteria can’t grow and good bacteria can. By the time the good-guy Lactobacillus are in charge of your ferment, they’re created enough lactic acid to prevent any baddies from moving in and taking over.
The goal is to create a brine that reaches that certain percentage of salt to water appropriate to whatever you’re fermenting. (Note: Some guides will tell you to calculate the brine percentage based not on the weight of the water, but on the weight of the water plus the vegetables inside the jar you’ll be using. I have personally achieved the best results by water to salt percentage, but you can also experiment by putting the jar on the scale, zeroing it out, filling the jar with the veg and water to get their weight, and then calculating the salt percentage on that basis.)
As I have a life-threatening allergy to math, this is my least favorite part of the process, but luckily the internet has many tools to make this calculation easier, like this brine calculator. That said, the metric system can help make these numbers simpler to grasp: If you’re making 2% brine from a liter of water, and a liter is 1,000 grams, then you need 2% of 1,000 grams—20 grams of salt—to hit your target.
You’ll note that brine math uses mass to measure salt, not volume. Salt is a many-splendored thing, and two tablespoons of one type of salt may have a totally different mass than two tablespoons of another. Unless you know the exact brand of salt used in a recipe, measuring by volume can throw your brine percentage way off, causing your ferment to fail. You can find fermentation recipes that use tablespoons or whatever, and you can try them out (I did!), but be prepared to suffer a lot of depressing failures before you dial in on how much of your particular salt you need to get the right brine.
The exact percentage of salt you want in your brine will depend on what you’re trying to ferment. While most vegetables do well with a 2%-2.5% brine, some softer vegetables (cucumbers or peppers, for example) benefit from higher salinity, and do better in a 5% brine. (Some folks will tell you onions are fine at 2%, but I composted a lot of failed onions before I found that in my particular kitchen microclimate, 5% for onions is the key.) There are lists online of suggested brine percentages for different vegetables, but some of this information will come as part of your own discovery process.
That’s partly because your unique household universe also affects how your ferments proceed. Ambient temperature is a huge factor, for example, as warmer temperatures accelerate fermentation, while colder ones slow it down. There are loads of different types of Lactobacillus bacteria and you may have more of one type in your environment than others, and that type may respond slightly differently than a book or guide might suggest. This process is a symbiotic one between you and all these tiny organisms transforming your food; it is normal for the unexpected to occur, and with every ferment that doesn’t quite work out, you’ll get smarter.
Making your first ferment
While there are loads of helpful implements for fermentation, you don’t need that much to get started. Your beginner level tools are:
- A food-grade glass vessel with a close-fitting lid (a big canning jar is perfect)
- A kitchen scale (Just buy one, you will use it way more than you think)
- Something that fits in your jar to serve as a weight (more on this below)
For the ferment itself you’ll need:
- Non-chlorinated room-temperature water (Filtered will work, or water that you’ve boiled and cooled completely.)
- Non-iodized salt (Sea salt or kosher salt are good; table salt, which is iodized, won’t work)
- Vegetables (I suggest you stick with just one type of veg to start with.)
- Seasonings, if you want them (Try garlic, spices, herbs fresh or dried, gochugaru, etc.)
- Bay leaves (Or use another tannin-heavy leaf; this is optional, but they can really help to preserve texture.)
How much brine should you make? The volume of your fermenting vessel should work just fine; if I am making a half gallon of vegetables, I’ll make a half gallon of brine. This is more brine than I need, but it’s a good idea to put the extra brine in a jar and stash it in the fridge in case you need to top up your ferments later.
Add your salt to your room-temperature water, and stir, stir, stir. Next, you’ll prep your vegetables. You can ferment almost anything. This is not to say it will definitely taste good, but experimenting is half the fun. Green beans and cucumbers are easy beginner friendly options. Carrots and cauliflower are also great; just keep in mind that denser vegetables may need a longer ferment. I’ve never had great luck fermenting radishes, personally.
Smaller pieces with more surface area ferment more quickly than bigger chunks, but they also may lose their texture in the process, so think about these things as you slice and dice. I would always rather scrub carrots than peel them, but you do you. Cucumbers should have the blossom ends removed, even if you’re fermenting them whole; that end contains an enzyme that will make your pickles mushy. You will get to know your vegetables well: how they ferment and what their strengths and weaknesses are.
Now it’s time to pack your jar. You want to seriously jam things in there as tightly as possible, but make sure you leave at least an inch of space at the top. Layer your vegetables with any seasonings, like garlic or pickling spices, and a bay leaf, if you’re using one. I advise against putting all the spices in at the top because most of them will float and make a mess. Once your jar is loaded, fill it with the brine.
There’s a whole team of friendly bacteria now waiting to make delicious homemade lacto-pickles for you, but they need one more thing for this endeavor to succeed: They need you to keep the vegetables submerged at all costs. You can do this with a glass fermentation weight designed to fit inside a wide mouth jar or a fermenting-spring gadget. Or, if you’d rather not invest in that stuff, you can fill a Ziploc freezer bag with some of your extra brine and smush it into the top of your jar. (Some fermenting blogs will say you can also use a literal rock that you’ve boiled clean as a fermenting weight—do not put a rock in your ferment, friends. Yikes.)
The weight is there to make sure that not even the tiniest bit of vegetable breaches the surface. Fermentation nerds have a saying that goes something like “UNDER BRINE, ALL WILL BE FINE” if that helps you figure out why that’s important. If you used a lot of spices, they may float; this is not ideal, but it probably won’t wreck your efforts. Just ensure your vegetables are under the brine, as any piece that floats above the surface creates a little raft for non-Lactobacillus invaders to latch on to. The most common of these is kahm yeast, a physically harmless whitish, powdery, film-like yeast that may affect the flavor of your batch. Some people will immediately dump a ferment that develops any kahm yeast at all; others just scrape the yeast off the brine surface and keep going. I’ve salvaged some and composted others. It’s really a matter of your personal comfort. Molds can also grow if your vegetables aren’t fully submerged, which is a death knell for that particular ferment.
Once you’ve ensured your vegetables are suitably submerged, you need a lid. There are many strong opinions about lids out there, and whether you should use an airlock type lid (example 1, example 2) to allow carbon dioxide produced during the fermentation process to escape. I started out using airlocks, but these days I use regular storage lids or (most often) a swing-top Fido jar, and I can’t say it’s made a huge difference for me either way. Go with your instinct on this, but if all you have is a regular lid, that should be fine.
Put your lid of choice on your jar as you normally would (no extreme tightening is necessary) and stash it somewhere out of direct sunlight; I keep ferments on top of my fridge. I strongly recommend you put the jar on something to catch any overflow; some folks put them on baking sheets, while I tend to stick mine in bowls. Depending on how full your jars are, there may be a significant amount of overflow, but this is good, actually: The less oxygen in your jar, the more likely your ferment is to succeed.
And now your work is done! Fermentation will begin, and your only remaining task is deciding when you want to eat it when ready. How long a ferment takes is extremely variable, so check your jar(s) carefully every single day to see how they’re progressing. Any time you handle your ferments, do so with freshly-washed hands to avoid accidentally introducing new bacteria to the jar. For the first day or so, nothing will seem to happen, but pretty soon you’ll notice changes, from color shifting, to the appearance of bubbles resulting from the aforementioned creation of carbon dioxide. These bubbles are a normal part of the fermentation process, and if you’re not using an airlock lid, you may want to open your jars periodically to release any built up pressure—but limit opening as much as you can. I’ve heard many a tale of an exploded jar that sprayed glass-shard-festooned cucumbers of death across an innocent kitchen. I’ve never had anything remotely close to that happen to me, but you’ve been warned.
Checking your ferment daily will help you learn what is normal. At the beginning, some ferments may smell a little questionable, but don’t rush to assume they’ve gone bad—sometimes they just need a little more time to settle into a vibe. When something has gone wrong and a ferment is truly bad, you will know. The odor will leave no room for uncertainty. Do not try to save something that smells horrible. Likewise, if you have a mold problem, that will be obvious, and if you see anything that looks like mold, especially red or black mold, dump the whole thing out and start again. If your brine seems to evaporate and it looks like your vegetables are in danger of surfacing, top it up with some of that extra brine you saved. (Aren’t you glad you did that?)
A finished fermentation will smell…right. Like fermented vegetables. It will taste a bit sour, a bit acidic, and a bit salty, but pleasantly so. You probably won’t recoil from the jar, unless you hate fermented vegetables, in which case I marvel at your commitment to reading this far. (If you’re not familiar with the aroma and flavor of fermented vegetables, buy some and eat them so you have a baseline.) It is also totally normal for your ferment to collect a sediment at the bottom, and for the brine to look cloudy as it reaches completion. I find most fermentations of cut vegetables are done in a week or so, but again, this will really depend on your situation. If you want to check the acidity to see if your brine has reached safe levels (below 4.6, although most lacto-pickles tend to “finish” around 3.5-3.0), I am a big fan of pH strips for peace of mind.
Once your ferment is “done,” it won’t just stop. If you don’t eat your pickles quickly, you can move it to the fridge to slow the ferment down, but fermentation will inexorably continue until every bit of consumable material has been depleted, not unlike what’s happening with the Marvel universe. That said, it will stay good in the fridge for quite awhile if, like me, you find yourself making more ferments than you can eat in a reasonable amount of time.