Fermentation:
Everything you need to know at a glance.
Your Guide to Fermentation: Basics and Helpful Tips for Getting Started.
What is fermentation?
Fermentation is a natural method of altering food using microorganisms such as lactic acid bacteria, yeasts, or certain molds, thereby preserving it. During this process, sugars and other components in the food are broken down and converted into new substances. This process is called fermentation.
The Benefits of Fermentation
Fermentation offers several benefits—for flavor, health, and sustainability. That is exactly why this traditional preservation method is making a strong comeback today.
Rich flavor and umami
Rich flavor and umami
Natural preservation without chemicals
Fermentation is a preservative-free method. Salt and lactic acid naturally protect food from harmful bacteria. This keeps vegetables, beverages, and dairy products edible for months—all without a refrigerator.
Sustainable and zero-waste friendly
Fermentation helps keep food fresh longer, make use of surplus harvests, and reduce food waste. It’s perfect for a resource-conscious kitchen.
Improved digestibility
During the fermentation process, carbohydrates, proteins, and dietary fiber are partially broken down. This makes foods easier to digest, often more easily absorbed, and better tolerated by many people.
Naturally rich in probiotics
Fermentation produces live lactic acid bacteria, known as probiotics.
More Nutrients
Unlike cooking or canning, fermentation preserves many heat-sensitive vitamins. In some foods, the vitamin content actually increases—for example, vitamin C and B vitamins in sauerkraut.
Here's what you need for fermentation
To ferment, you only need a few simple items, and you probably already have most of them at home. The key ingredients are fresh vegetables, natural salt (without anti-caking agents), and a clean glass jar with a lid or a fermentation valve. The salt helps inhibit unwanted bacteria and allows the lactic acid bacteria to thrive. Also, the vegetables should always be completely covered with liquid. Weights or a small glass weight are handy for this. A cutting board, a knife, and a little patience are all you need to get started.
Here's how it works
The fermentation process is usually straightforward: First, the ingredients are prepared and cleaned, then mixed with salt or starter cultures and placed in a clean container. To create optimal conditions, contact with air should be avoided as much as possible. The actual fermentation process then begins, which can take anywhere from a few days to several weeks, depending on the food. Finally, the fermented foods are checked regularly and stored in a cool place.
Fermentation is a natural process in which microorganisms such as lactic acid bacteria, yeasts, or fungal cultures convert sugars and other nutrients into new substances such as lactic acid, carbon dioxide, or alcohol. Lactic acid bacteria play a particularly important role in vegetable fermentation: They multiply under low-oxygen conditions and produce lactic acid, which lowers the pH and naturally extends the food’s shelf life. Salt further supports this process by inhibiting unwanted bacteria and creating optimal conditions for the desired microorganisms. During fermentation, this not only alters the shelf life and texture but also the flavor and aroma. Simple ingredients are thus transformed into complex, slightly tangy, and distinctive fermented foods.
The Most Popular Fermented Foods
Fermented foods are becoming increasingly popular, and for good reason. Natural fermentation produces intense flavors, extends shelf life, and provides valuable probiotics.
We’ve been familiar with many of these foods for centuries through traditional cuisines around the world. Whether it’s sauerkraut, kimchi, kombucha, yogurt, or sourdough—each fermented food offers its own unique flavor and health benefits.
Fermented vegetables are one of the easiest and most popular ways to get started with fermentation. Salt and natural lactic acid bacteria preserve the vegetables, give them an intense flavor, and ensure they remain rich in valuable nutrients. Whether carrots, cabbage, cucumbers, or bell peppers, almost any vegetable works. They’re perfect for a healthy, fiber-rich diet and ideal for enjoying the seasonal harvest for longer.
Kimchi is a traditional Korean fermented dish made from napa cabbage, garlic, ginger, and chili peppers. Its spicy, tangy flavor makes it a real flavor booster for bowls, rice dishes, and soups. Kimchi is a classic for anyone who loves fermented foods.
Fermented dairy products such as yogurt, kefir, and skyr contain live cultures. They have a fresh, mild, or slightly tangy taste and can be easily incorporated into breakfasts, snacks, and smoothies.
Sourdough is created through the fermentation of flour and water. Natural yeasts and lactic acid bacteria give it an aromatic flavor, a light crumb, and make it easier to digest. Compared to industrial bread, sourdough bread contains fewer additives and is often easier to digest. It also stays fresh longer. Perfect for anyone who enjoys mindful eating and wants to bake their own bread.
Some of the best-known fermented beverages include kombucha, water kefir, and ginger beer. Natural yeasts and bacteria give them a slightly fizzy quality, and they contain probiotic cultures. Many people enjoy them as a refreshing, low-sugar alternative to soft drinks. Their vibrant flavor ranges from mildly sweet to pleasantly tart.
Possible Problems During Fermentation
Things can sometimes go wrong during fermentation. But most problems can be easily avoided. Mold often forms when the vegetables aren’t completely submerged in the brine. So always make sure everything is well covered and use clean jars and utensils whenever possible. Another problem is unpleasant odors: During the first few days, the smell is often stronger, but afterward, the fermented mixture should have a fresh, tangy aroma—not a rotten one. If the vegetables become too soft or mushy, it’s usually because the salt content was too low or the temperature was too high. The ideal conditions are about 2% salt and a room temperature of 18–22 °C.
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Frequently Asked Questions
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Yes, fermentation works very well at home, often without any special equipment. All you need is fresh vegetables, salt, a jar with a lid or an airlock, and a clean workspace. Nature takes care of the rest. It’s important to make sure the vegetables are completely submerged in the brine to prevent unwanted bacteria from growing. Many beginners start with sauerkraut, kimchi, or fermented carrots, as these turn out well every time. Fermenting at home is inexpensive, sustainable, and fun.
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Fermentation is the process by which natural microorganisms, such as lactic acid bacteria or yeasts, transform food. They break down sugars, producing acid, gas, or flavor in the process. This preserves the food, gives it a richer flavor, and can result in the presence of health-promoting probiotics. This happens all on its own as soon as the food is left to rest in brine or in a controlled environment. In other words, microorganisms are deliberately used to improve flavor, shelf life, and digestibility—all without additives or cooking.
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To ferment, you usually just need vegetables, salt, a clean jar, and time. The vegetables are cut, mixed with about 2% salt, and pressed firmly into the jar so that juice is released and they are completely covered by the brine. The jar is then sealed and left to sit at room temperature for a few days to a few weeks. The natural lactic acid bacteria begin to work, converting sugar into lactic acid, which develops flavor and extends shelf life.
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Many foods are suitable: Vegetables such as cabbage, carrots, cucumbers, and radishes are particularly popular. Dairy products can also be fermented, for example, into yogurt or kefir. Grains become sourdough, tea becomes kombucha, and soybeans become miso or tempeh. Even fruits and herbs can be fermented. It’s important that the food be fresh and clean when processed. This variety makes fermentation a creative way to discover new flavors and textures.
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The minimum duration depends on the food. Vegetables usually take 3 to 7 days for the first flavors to develop. Sauerkraut often ferments for 2–4 weeks to develop a fuller flavor. Sourdough starters develop in 5–7 days, and kombucha in 7–14 days. The longer the fermentation process continues, the more intense the flavor becomes and the longer the shelf life. It’s important to taste it regularly to determine when it has reached the desired flavor.
You can find all FAQs and answers here.