Fermentation for beginners: why, how and what to watch out for

Fermentation is experiencing a renaissance, sourdough bread, kombucha and our kimchi all rely on the same principle: you let microorganisms do the work for you. For a beginner this may sound like alchemy, but the basics are simple and safe if you follow a few rules. In this article we will cover why you should try fermenting at all, what can be fermented at home, what equipment you need and how to safely tell when a jar should be thrown away.

Fermentation is the oldest method of preserving seasonal harvests for months in advance, long before refrigerators existed. Lactic acid bacteria break down sugars in vegetables into lactic acid, which acts as a natural preservative while giving the vegetables a more pronounced, tangier and deeper flavour than raw or heat-treated produce.

On top of that, it is an excellent way to process surplus vegetables from the garden or a farmers' market without having to eat them all at once or freeze them. Fermentation actually enhances the vegetables, turning ordinary cabbage or carrots into a distinct, standalone ingredient.

Fermented foods also contain live lactic acid bacteria, probiotics, which neither raw nor cooked vegetables can boast of. We write in more detail about what fermentation brings in the article Health benefits of kimchiAt Kimchi & Prosecco courses, fermentation takes place live and participants take their own jar home: the full process is also described in the article. How to make kimchi at home.

Almost any vegetable and some beverages can be fermented. The easiest place to start is:

• Kimchi & Prosecco - a classic that never fails and also the foundation for our Kimchi & Prosecco
• Pickles - crunchy sourdough pickles without vinegar, just salt and water are needed
• Carrots, radishes and cauliflower - quick vegetable smoothies, ready within a few days
• Peppers and chillies - fermented paste is suitable for sauces and marinades
• Kombucha fermented sweetened tea using vinegar fermentation
• Kefir and water kefir - a milk or water-based beverage fermented with kefir grains

Kimchi is essentially just a specific variant of vegetable fermentation, Chinese cabbage enriched with gochugaru chilli, garlic and ginger. Anyone who can ferment sauerkraut can make kimchi without any problems.

To get started, you don't need any expensive equipment:

• Wide-necked glass jar or ceramic fermentation vessel
• Kitchen scale: the salt-to-vegetable ratio must be exact
• Coarse uniodised salt: iodine inhibits fermentation bacteria
• A fermentation weight or a small bag of water to keep the vegetables submerged under the brine.
• Rubber gloves, especially when working with caustic paste.
• A clean napkin or gauze to cover the container

The most important rule of fermentation is simple: the vegetables must remain fully submerged in the brine at all times. Once exposed to air, you risk mould growth.

The fermentation time depends on the temperature, the amount of salt and how strong a flavour you want. At room temperature (18-22 °C), most vegetable ferments are ready in 3 to 7 days, with the first bubbles appearing after 24 to 48 hours. The warmer it is, the faster, but also the sooner the fermentation will "over-ripen" and the flavour intensify.

In the fridge, the process slows down significantly, so you can store the finished ferment for weeks or even months while the flavour continues to develop slowly. The best way to tell when fermentation is ready to your taste is simply to taste it: a spoonful a day will tell you more than any universal recipe.

Fermentation is safe if you follow basic hygiene rules, but there are a few signs you should not overlook.

In practice, a simple rule applies: when in doubt, throw it away. The risk is certainly not worth a single taste. Fermentation can also be given as a gift, how the gift course works is described in the article. Kimchi as a gift.

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