Lacto-fermentation is an age-old process where beneficial "friendly" bacteria, known as lactic acid bacteria (LAB for short), transform vegetables into more nutritious and complex flavored foods with an extended shelf life. These microorganisms break down complex molecules into simpler, more digestible substances, increasing the bioavailability of vitamins, minerals and enzymes. Food that has been fermented supports our digestive system, and enhances the health of our gut flora. The health of our gut flora is essential to our overall well-being, especially our immune system.
Lacto-fermenting at home is easy, safe and economical. It can be accomplished without investing in any special equipment. With nothing more than salt, water and the bacteria already living on your vegetables, you can transform cabbage into more digestible sauerkraut, and perishable cucumbers into long-lasting pickles. All you need are some clean wide-mouthed canning jars with their lids, and some uniodized salt. A kitchen scale is optional, but useful. You can purchase special fermentation lids that allow gasses to escape, and weights to keep the vegetables submerged, but these functions can be easily accomplished with items on hand.
Before jumping into specific recipes, it's important to understand a few basic principles of lacto-fermentation. The goal is to create an environment that encourages the proliferation of beneficial bacteria, while preventing the growth of harmful bacteria. This can be achieved by immersing the vegetables in a salty brine. Salt creates an inhospitable environment for undesirable bacteria and molds. However, the beneficial LAB can handle the salt and create their own acidic environment by forming lactic acid as a byproduct of metabolism. The process by which the LAB breaks down vegetables and produces lactic acid is anaerobic, so it's important to keep the fermenting vegetables submerged in the brine and protected from exposure to oxygen.
Dry salting (or self-brining) is used for vegetables with a high moisture content, such as cabbage. Self-brined vegetables have to be shredded into very fine pieces to increase the surface which allows the salt to penetrate into the vegetable and draw out large amounts of liquid.
Vegetables with a lower moisture content are usually fermented in larger pieces in a saltwater solution, a process known as "wet-brining." This technique is also used for vegetables that would be texturally unappealing if grated, such as cucumbers.
The optimal salt concentration for lacto-fermenting most vegetables is between 1.5% and 3%.
Too low a concentration will lead to rot. Too high a percentage of salt will kill off all bacteria, including the LAB. Our ancestors would have relied on taste and trial and error to determine how much salt to use. However, first-time fermenters need guidelines. A typical recipe for sauerkraut might call for adding 1½ tablespoons of kosher salt to a medium head of green cabbage. Though this formula will yield acceptable results most of the time, it's very imprecise. How big is a medium head? What type of kosher salt are you using: Diamond Crystal or Morton's? Different salts have different crystal sizes. To achieve the same degree of saltiness as a tablespoon of Morton Kosher salt, you would need to use 1.85 tablespoons of Diamond Crystal Kosher salt.
The most reliable method is to measure the salt by weight rather than by volume. My Ozeri kitchen scale cost me less than $12 and I use it constantly. If I'm making sauerkraut by dry salting and I want to achieve a 2% brine, I'll weigh the shredded cabbage and multiply that weight by .02 to determine how much salt to add. If I'm fermenting cauliflower and want a 2% wet brine, I would tightly pack my vegetables into a jar and cover with enough filtered water to fully submerge them. Next I would multiply the total weight of the vegetables and water by .02 to determine how much salt to add.
After determining how much salt to use, the next step is to pack the prepared vegetables into clean wide-mouthed canning jars. The jars should be filled to no more than an inch from the top, and the vegetables should be totally submerged under the brine. Special fermentation weights can be used to keep the vegetables from floating to the top, but an equally effective method is to fill a resealable plastic bag with some extra brine to weigh down the vegetables.
As the vegetables ferment, gases are formed which need to be released in order to keep the jars from exploding. You can purchase special fermenting lids with airlocks or one-way vents to allow the gases to escape, but an effective low-tech option is to "burp" the jars every day by partially unscrewing the lids to release the built-up gases.
Self-brined fermentation: Sauerkraut
1 medium head of cauliflower
Uniodized salt (kosher or sea)
Distilled or filtered water
Optional: caraway seeds or juniper berries
Thinly slice the cabbage.
Weigh the cabbage in grams, and multiply that weight by .02 to calculate the weight of salt to add. Sprinkle the salt over the cabbage and massage until liquid is released – about 10 minutes.
Add the caraway seeds or juniper berries (if using).
Pack the cabbage and liquid into a jar and press down until the cabbage is submerged.
Add a weight or a brine-filled zip-close bag to keep the vegetables submerged. Cover jar with a canning lid or fermentation lid. If using a canning lid, loosen and burp daily to release gases.
Ferment at room temperature for at least two weeks, then move to the refrigerator.
Wet-brined fermentation: Lacto-fermented cauliflower
1 small cauliflower
4 garlic cloves, smashed
2 dried chilis
Filtered or distilled water
Uniodized salt (kosher or sea)
1 tablespoon curry powder
1 tablespoon chili powder
1 tablespoon turmeric powder
1 teaspoon cayenne
Rinse and cut the cauliflower into florets.
Pack your fermentation jar with the cauliflower, chilis and garlic cloves. Leave one-inch space between the top of the vegetables and the rim of the jar.
Cover the vegetables with enough water to fully submerge them, and note the total weight of the water and vegetables (less the weight of the container). Multiply the total weight by .02, and measure that amount of salt into a mixing bowl. Pour off the water from the vegetables into the mixing bowl, stir until the salt is dissolved, add the remaining four spices, and pour the liquid back into the fermentation jar.
Add a weight or a brine-filled zip-close bag to keep the vegetables submerged.
Ferment at room temperature for 3-5 days, then refrigerate. Cauliflower will keep refrigerated for at least two months.
Peter welcomes readers' questions. He can be reached at email@example.com.