Fermentation – what’s it all about

Fermentation – what’s it all about


The difference between Wild Fermentation, Lacto-Fermentation, Culturing and Pickling Adapted from: The Wild Gut

There is nothing new about Fermentation – humans have been utilising it as a way to preserve foods since the Neolithic era.  Way back then, it was simply a way to ensure that there would be nutritious food to eat through the winter months when there was little fresh food around.  Today, it is said to be one of the biggest food trends around.

It is still the case that there are many people using fermentation for its preservation qualities, many others are beginning to recognise the huge heath benefits of including fermented foods and drinks in the diets daily.  Research is showing that there are many positive effects with much work being done on the link between gut health and mental health. It’s fascinating to think about the microbiota in the gut having a positive (or negative) impact on the brain and emotional and mental well-being.

Probiotics have a range of positive effects on health, including the improvement of various intestinal inflammatory conditions, positive impacts on the immune system and even weight loss. They can alter the composition of the gut microbiome crucially affecting digestion, elimination and the absorption of nutrients.

What is Fermentation?

When it comes to food, fermentation simply refers to the metabolic process that converts sugar to acids, gases, or alcohol. This results in the uniquely flavoured food that fermentation enthusiasts love.

Fermentation is a mostly anaerobic process (meaning without oxygen) carried out by micro-organisms. These micro-organisms convert sugars, such as glucose, into other compounds, such as alcohol, to produce energy to fuel their metabolism. Bacteria and yeasts (which undergo lactic acid fermentation and ethanol fermentation, respectively) are used in the fermentation of foods. The unique flavours and textures of fermented foods are due to the different species of bacteria and yeast used.

What types of fermentation are there and how are they different from each other?

When it comes to fermentation, there are three terms widely used: wild fermentation, lacto-fermentation and culturing (pickling, as you will see below, really doesn’t come into the conversation). Although these ideas overlap, they are actually three different processes. These terms are often used interchangeably, so it’s good to see what the differences are, and better understand what is happening with these foods.

Wild Fermentation

Wild fermentation occurs when microbes naturally found on foods or in the air are used to initiate the fermentation process. Essentially, spontaneous fermentation. Wild fermentation is often a first introduction to the world of fermented food and drinks. For example, the initial process of creating a sourdough starter illustrates wild fermentation, as it utilises wild yeasts found in the air. That is why a sourdough starter originating in Bridport will taste subtlely different from a sourdough starter originating in Bradford: different locations, different yeasts in the air!

Sauerkraut is also an example of wild fermentation. Sauerkraut utilises the naturally occurring lactobacillus bacteria on the cabbage, to break down and ferment in an anaerobic environment.

If left exposed to oxygen, the cabbage would simply mould and rot. The anaerobic environment combined with a little salt keeps the bad bacteria away and allows the beneficial probiotic bacteria (lactobacillus) to produce lactic acid. The end result is the sour-tasting fermented cabbage that we call sauerkraut.  Other examples are miso, kimchi, apple cider vinegar and ginger beer.


Lactic acid fermentation (AKA: lacto-fermentation) is a variant of wild fermentation. Lacto-fermentation refers specifically to lactobacilli bacteria. Lactobacilli are present on anything grown in the earth. So, sauerkraut is actually an example of both wild fermentation and lacto-fermentation. The naturally occurring lactobacillus bacteria found on the cabbage feed on sugars in the cabbage and produce lactic acid as a by-product.


Many non-fermenters will inter-change the words “fermented” and “cultured”, and in many cases it doesn’t really make much difference which word is used.  However, in fermenting circles, culturing generally means there has been some sort of microbial starter used to initiate fermentation. Common microbial starters include whey, grains, SCOBYs and powdered starter cultures. Water kefir is an example of culturing. The water kefir grains are actually lentil-sized symbiotic colonies of yeast and bacteria. These grains feed on sugar water producing a cultured beverage containing beneficial yeast and bacteria.  Under the culturing heading you would find water kefir, milk kefir, kombucha and jun.

As you can see, a wild ferment can also be a lacto-ferment, but not always. A lacto-ferment is a wild ferment. And culturing is a fermentation process where a microbial starter is used.  And not all fermented food/drink is full of probiotics – table vinegar, wine and beer being obvious examples.


Foods that are pickled are those that have been preserved in an acidic medium.  In the case of various types of supermarket pickles on the shelf, the pickling comes from vinegar.  These vegetables, however, are not fermented (even though vinegar itself is the product of fermentation) and hence do not offer the probiotic and enzymatic value of homemade fermented vegetables.

One question that often arises is “can these bacteria survive the stomach?”  From many research studies, it seems that the bacteria in fermented dairy and vegetables can indeed survive their perilous journey through the digestive tract. Once they are there, it’s clear that they have at least some positive effects on human health, ranging from the enhanced nutritional contents of the foods themselves, to alleviation of inflammatory bowel conditions, to restoring normal gut microbiota after antibiotics, to enhancement of the immune system, and possibly even weight loss. It would be nice to know more about the mechanisms of these effects – and maybe we will know soon, because it is currently a hot area of research.

Some common fermented / cultured foods:


Coffee beans are surrounded by a stubbornly sticky pulp. After picking, they are crushed to loosen the pulp, then fermented. The length and technique of the fermentation process, along with roasting, determines the final flavour of the coffee.


Fermentation is a crucial step in chocolate production, removing bitter tannins and imparting flavour complexity.


The differences among teas can largely be explained by the method of processing, as most teas come from very similar plants. All teas are oxidized, but some teas undergo a second fermentation that imparts a unique flavour.

Sourdough Bread

Sourdough bread is fermented with the help of wild yeasts that are unique to a region, climate, or even a kitchen. Mixing wild yeast culture into flour and water to make bread will create bubbles that cause the bread to rise, and give the bread a characteristic sour taste.


Cheese is really milk gone bad (in a controlled way). All cheese consists of milk, culture, and sometimes coagulant. Different cheeses began with different cheese cultures, some of which have been handed down for generations.


Yogurt is milk that has been cultured with two very specific strains of bacteria: streptoccus thermophilus and lactobacillus bulgaricus. Most shop-bought yoghurts are filled with artificial additives, colours, and sweeteners. When shopping, look for plain yoghurt containing nothing but cultures and milk. Or make your own.


Kefir is sometimes known as drinkable yoghurt, and is a cultured dairy product similar to yoghurt, but it contains more strains of friendly bacteria than yoghurt.


Sauerkraut is another very simple home fermenting project. You can ferment cabbage easily with just salt, or you can use a lacto-fermentation method by adding a little yogurt whey.

Traditionally, dill pickles were made through fermentation. Now they are most often made with vinegar. The traditional types are making a resurgence, however, and can be found in specialty shops carrying local products. Or you can make them yourself.

There are more varieties of kimchi than cars, but all have a delicious funk in common, and that funk comes from fermentation. Kimchi is made like sauerkraut but may contain different types of vegetables and seasonings, and sometimes dried or fermented fish paste.

This popular drink is the product of a very specific culture. The culture is a spongy, slightly slimy disc that is sometimes called ‘the mother’ and sometimes called a SCOBY. The culture ferments a mixture of black tea and sugar into a tart, slightly fizzy drink that some people insist is a cure-all for many ailments.

Fish Sauce
In Thai and Vietnamese cuisine, the fish sauce is made of mashed up whole fish, packed in salt and fermented. But beware. Not all fish sauce is created equally. Some brands are produced through a chemical process, not a natural fermentation process.

Vinegar is made by fermenting wine with a mother, which is a stringy mass of bacteria found in unpasteurised vinegar. It’s easy to make vinegar at home from leftover wine and culture, either purchased or obtained from another vinegar.

The salty paste used in Japanese cooking is made with a special koji culture, rice or barley, and soybeans. Many people think it’s the key to Japanese longevity.

This meaty tasting soybean cake, popular in Indonesian cuisine is a product of fermenting cooked soybeans with a special mould. If the tempeh sometimes appears mouldy, that’s because it is. But rest assured, it’s like the mould in blue cheese and ok to eat.



Vegetables fermented at home using a starter, salt, and some filtered water create their own self preserving, acidic liquid that is a by-product of the fermentation process. This lactic acid is incredibly beneficial to digestion when consumed along with the fermented vegetables or even when sipped alone, as anyone on the GAPS Intro Diet has discovered (cabbage juice anyone?). In other words, homemade fermented veggies are both fermented and pickled.

Home fermentation of vegetables does not use any pressure or heat unlike supermarket versions of the same foods.  It allows the beneficial lactobacilli present on the surface of all living things, even your own skin, to proliferate creating lactic acid. This not only ferments and preserves the vegetables, but also promotes the health of those that consume them because fermenting:

  • enhances the vitamin content of the food,
  • preserves and sometimes enhances the enzyme content of the food,
  • improves nutrient bio-availability in the body,
  • improves the digestibility of the food and even cooked foods that are consumed along with it.


Adapted from: The Wild Gut