A Beginner’s Guide to Fermentation

Four sealed, glass jars holding a variety of fermented vegetables.

Fermentation gets a bad rap. When most people think of fermentation, their minds conjure up unappetizing images of bacteria growth, yeasty molds, and other signs that food has gone bad. But in the case of developing deliciously sour and boldly flavored ferments, microbial activity is actually what you want to see.

“Fermentation is science plus magic. It is alchemy,” says Amanda Feifer, a fermentation specialist. “You put something in a jar and 10 days later, come back to it and it has completely transformed without you having done anything to it.” Feifer has been fermenting for about a decade and in addition to her blog, Phickle, and the fermentation workshops she runs, she is the author of the book Ferment your Vegetables.

In recent years, culinary trends have positioned fermented foods as a kind of specialty, but the art of fermentation is more common than you think. In fact, humans have been harnessing the power of fermentation for thousands of years, using it as a way to preserve foods and to add complex flavors to their meals.


"Fermentation is science plus magic; it is alchemy. You put something in a jar and 10 days later, come back to it and it has completely transformed."


“The flavors that are produced during fermentation are really unique. It’s hard to get there other ways,” says Feifer. “There’s a reason alcohol has these complexities to it. Cheese is also a really interestingly developed food and so are certain sauces. Flavor, richness, umami – all these different kinds of flavor compounds are produced during fermentation.”

You likely don’t go a day without eating something that is fermented. “It is a part of our staple diet,” says Feifer. Sourdough bread, yogurt, cheese, wine, beer, pickles, and hot sauces are just a few examples of commonly enjoyed foodstuffs that have been transformed through fermentation.

For beginners, fermentation can be daunting, especially when you think of the complex sterilization processes and expensive equipment required to brew beer and ferment wine. But fermenting vegetables, making pickles, and developing tangy sauces are actually quite simple and don’t require a lot of materials.

A sealed, glass jar holding fermented radishes.
Chopped red and green cabbage resting in separate bowls.

According to Feifer, a great place to start is fermenting vegetables. Not only do they taste phenomenal, but the transformation helps extend their shelf life from a couple weeks to a few months as long as you keep them in the refrigerator once you’ve fermented them to your liking. You can use either fresh vegetables, or vegetables that you’ve forgotten in the back of the refrigerator. “As long as [your vegetables are] not moldy or soft,” says Feifer. “Once it’s fermented, a lot of times you can still get it transformed enough or you can turn it into a condiment that you can add to other foods.”

All you need is a jar, salt and water (for the brine), a fermentation weight (something to keep your vegetables submerged in the brine), the vegetables you want to ferment, and time. The “perfect pickling window,” as Feifer calls it, is around two weeks, but that time frame may shift depending on the temperature of the room where your ferments are being kept. According to Feifer’s book, temperatures between 64°F and 78°F will work just fine, but keep in mind that the temperature you start out with can influence which strain or strains of lactic acid will initiate the fermentation, which may slightly change the flavor of your ferments.

Your flavor preferences will also determine how long your vegetables ferment, which is why you should be taste testing them every now and again until they’ve reached your desired flavor profile.  Sourness is the thing that changes and grows over time. “This isn’t canning where it’s preserved and will stay relatively the same over time while in storage,” says Feifer. “Ferments are living foods and they will change over time.”  Once you like the taste of your ferments, Feifer recommends moving them to the refrigerator.

Three glass jars holding fermented radishes, red cabbage and green cabbage.
Two glass jars holding fermented radishes and red cabbage.
A metal strainer filled with freshly cleaned, whole radishes.

Salt is another variable that can slightly change the flavor of your ferments but unless you have an incredibly refined palate or you’re a supertaster, you won’t be able to tell. Feifer says that any salt will do. She has experimented with all kinds of salt, from salt packets from fast food restaurants to fancy salts from boutique companies, and she says she didn’t notice a dramatic difference. However, the size of the grain will determine the quantity of the salt that goes in, which is why some fermenting fanatics measure salt by weight. Feifer recommends that for fine salt, go lighter, and for coarse salt use a little more.

Your first attempts at wrangling wild bacteria can be intimidating, but it’s not hard to determine if your ferments are good to eat. For the most part, fermentation is relatively safe and it’s hard to mess up. But always trust in your senses, particularly your sense of smell. “Any red flags will announce themselves to you with bright shining Vegas lights,” says Feifer. “You will know by looking at it and by smelling it that it is not okay. But if the smells gets your saliva glands tingling a little bit and it looks good, then it wants to be eaten.”

Between room temperature, time, and ingredients there’s a lot of room to experiment. So grab whatever vegetables you can find and see what kinds of funky flavors you can ferment!

A glass bowl filled with sliced, salted red cabbage.
Three glass jars holding fermented radishes, red cabbage and green cabbage.