People have been fermenting food since at least 6,000 B.C., and most cultures have some sort of fermented food.

In Asia, that includes various vegetable pickles such as kimchi, as well as soy sauce, fish sauce, tempeh, and miso. In Europe, there are sauerkraut, olives, kvass, cheese, yogurt, sausages, and Worcestershire sauce. In Central America, Salvadorans make curtido, a sauerkraut flavored with onion and chiles. In North Africa, preserved lemons flavor many dishes.

Interest in making and eating fermented foods is at an all-time high in the United States, in part because America’s global food culture has embraced the fermented foods of different cuisines. There is also interest for health reasons.

Fermented foods, such as sauerkraut and kimchi, are rich in probiotics, live microorganisms that work by improving or restoring the bacteria that naturally occur in our guts, and aid digestion. Eating foods packed with probiotics—good bacteria—is one way to boost your gut health, which in turn improves brain health and overall health. These good bacteria—the probiotics—grow during fermentation.

Gateway Ferment

Combine salt and vegetables and let the bacteria do their thing in an anaerobic (“without air,” since bad bacteria need air to live) environment, and you get fermentation.

The salt draws the water out of the vegetables’ cells and creates a brine. Then, the bacteria kick in, digesting the naturally occurring sugars in the food and releasing carbon dioxide and acetic and lactic acids, which give the ferment its distinctive, tangy flavor.

If you are new to making fermented pickles, the easiest and least expensive vegetable to start with is cabbage. Grate the cabbage, combine it with a fine sea salt (one with no additives), pack it into a clean canning jar (no crock needed), and let the fermentation begin! In two weeks, you’ll have sauerkraut.

A Note on the Formula

A kitchen scale is needed for recipes, such as sauerkraut, that specify ingredients by weight. The weight measures are necessary to ensure the correct proportion of salt to vegetable. Not everyone follows the recipes exactly, though I do, and I recommend that beginning fermenters do, as well.

The USDA standard for fermenting vegetables is three tablespoons of salt per five pounds of vegetables. You can start with less than five pounds, as long as you also scale down the salt. If you increase the amount of salt, the fermentation process will be slowed down, but the vegetables will keep longer; decreasing the amount of salt will speed up fermentation, but your pickles will be more vulnerable to spoilage. There are plenty of picklers who just salt by taste.

Breaking It Down

When you first combine the cabbage with the salt, you can wait until the salt draws the water out of the cell walls to naturally create a brine, or you can mechanically crush the cell walls with your hands, a wooden dowel, or a potato masher to facilitate the process. You’ll need to generate a brine before you can pack the sauerkraut in a crock or jar.

Use muscle to pack the vegetables tightly in your jars. I use a one-inch wooden dowel for tamping down the mixture as I pack. You can improvise with another tool, but whatever you use, keep packing and pressing as you go. The vegetables should exude enough liquid to be completely covered by brine.

You’ll need to exclude air from your ferment to protect it from airborne yeasts, molds, and bacteria. The easiest way to do this is to fill your jars to the very top with vegetables and brine, then gently place the lids and screw bands, barely tightened, on top, and set the jars on saucers to catch the overflowing brine—and they will overflow, once the fermentation starts and carbon dioxide bubbles begin rising to the top. Loosen the screw band after a few days, or if the lid starts to bulge, to prevent the jar from exploding.

As the vegetables ferment, their flavor goes from sharply salty to mildly sour. Because fermentation is a natural process, it progresses naturally—faster in warmer temperatures and faster with vegetables that contain more sugar.

Sauerkraut takes ten to twenty days to ferment. Before then, don’t open the jars. Each time you open them thereafter, to taste, you will need to top them off with a tablespoon or two of extra brine. 

The Finish Line

When the vegetables are more sour than salty, the fermentation has pickled the vegetables. You can slow down further fermentation by refrigerating the pickle, or you can let the fermentation continue until it reaches your desired level of sourness. It is perfectly fine to halt the fermentation before the kraut is fully soured.

Eventually, all the sugars in the vegetables will have been digested, completing the process. Fermentation is complete when gas bubbles stop rising to the top of the jar.

Store your sauerkraut in the refrigerator. Over time, the pickles will soften and darken in color. The sauerkraut is best eaten within six months; if you want to make sauerkraut that lasts longer, increase the amount of salt.

SIDEBOX

Step by Step: Making Sauerkraut

1. Wash, clean, sanitize

Start by washing all bowls, canning jars and lids; your knife, grater, or mandoline; and your tamping tool.

2. Prepare the vegetables

Wash the cabbage carefully. Weigh it and do the math: In general, you’ll use three tablespoons of fine pickling or sea salt for every five pounds of vegetables. Very thinly slice or grate the cabbage.

3. Add the salt

Work the salt into the veggies, mixing and pounding with a potato masher or your hands to break down the cell walls. Alternatively, mix well, cover the bowl, and leave for about 4 hours. The salt will draw water out of the cells and wilt the cabbage.

4. Pack the jar

Pack the vegetables in the jars. Tamp down on them until they release enough liquid to cover them.

5. Cover

Fill the jars with brine to the top. The cabbage should have generated enough brine, but if not, make additional brine by dissolving 1 1/4 teaspoon fine sea salt in 1 cup water and add as needed.

Cover the jars with their lids, then loosely affix the screw bands. Set the jars on a saucer to catch the brine that will overflow once fermenting starts.

6. Allow the pickles to cure

Set the jars where the ambient temperature will remain between 65 and 75 degrees F, if you can. Fermentation should begin with a day or two, depending on the temperature. If you gently tap on the jar, you should see gas bubbles rising.

Begin tasting after 10 days. Once the kraut is cured to your satisfaction, refrigerate it to halt the fermentation.

Andrea Chesman is the author of many cookbooks focusing on homesteading skills and cooking from the garden, including “The Pickled Pantry” (Storey Publishing).