Fermentation. What is this beast?

Fermentation and fermented products, like sourdough bread, yoghurt, kimchi, sauerkraut have become quite fashionable in the past years for their ability to improve the health of our gut microbiota, but this kind of preparation is nothing new really, even if it is a new diet and gastronomy fad today. I have been eating fermented pickles and sauerkraut my whole life as it is part of Latvian culture, so it is quite curious to see these things offered as some kind of innovation.

Photo by Michael Schiffer on Unsplash

Fermentation is probably the oldest way of how to preserve food over long periods of time. There was no fridge even 200 years ago, but humans have lived since way before that! And food, especially during winter time had to be preserved somehow to maintain good and varied nutrition.

Microorganisms were the first to populate the earth, so they have accompanied the evolution of humans since the beginning of time. Even our gut contains billions of bacterias that help us digest, absorb, keep good health, control our digestive and even nervous system. If we take care of them, they can keep us in good health but if we don’t keep good nutritional habits, other unwanted microbes can overpopulate our gut and increase the possibility of suffering from such diseases as Alzheimer’s and heart disease. The bacteria in our bodies outnumber our unique DNA by more than 10 to 1!!! (The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from Around the World)

But we’ll talk more on our gut microbiota another time, as it is such a complex thing and first we need to talk about fermentation!

I have already mentioned this one, but considering the theme here, I’ll do it again. A fantastic book on the human microbiome, how or gut microbiota influence the wellbeing of our mental health and holistic physical health.

Why do we need to ferment anything anyway?

For me this is quite an interesting topic, especially because the word “to ferment” is more than often used wrongly in the gastronomy industry even by specialists, especially coffee and tea. So instead of describing types of fermentation for these industries, it’s better to understand how fermentation works in general.

Wine, beer and other alcoholic beverages, different in all countries and cultures, come from the miracle of fermentation.

Bread, the base of the Mediterranean diet – fermented.

Cheese, for goodness sake! A fundamental part of our (mine for sure!!!) diet!

Things would ferment with microorganisms floating in the air or being present already on the foods in the correct conditions without human help, of course. But we have learned how to control the fermentation to our benefit, and to produce tastier, more digestible food, or spectacular products such as chocolate, coffee, wine etc.

Let’s get it straight – fermentation is an anaerobic metabolism.

Biologically speaking, fermentation is an anaerobic metabolic process, meaning it needs no oxygen to produce nutrients. Microbes were the first to populate the earth when there was not even sufficient oxygen in the atmosphere for aerobic organisms (like animals and humans, for example) to survive. It is thanks to their evolution and their existence, that aerobic organisms evolved.

What does anaerobic mean? The process doesn’t require oxygen to be carried out. It doesn’t mean that all microorganisms, like bacteria and yeasts, have to be in an oxygen-free environment, it just means that fermentation biologically and chemically doesn’t use oxygen in the metabolism. Correctly speaking, everything that uses oxygen in the metabolism, like our mitochondria in the cells producing ATP (energy) is called oxidation, also known as cellular respiration.

In many cases distinguishing whether it is an anaerobic fermentation or an aerobic oxidation determines a desirable or undesirable action in a product. For example, if speaking about wine, Saccharomyces cerevisiae eats sugars and in an anaerobic process creates energy and ethanol and CO2 as byproducts. Brettanomyces on the other hand is a microorganism that works in aerobic conditions and if very active, it can produce very unpleasant aromas in wine.

Of course, that is not always the case! There are microorganisms work in moth conditions, just produce different compounds at different stages.

That brings us to the point…

This is a fantastic book to read to learn about the fermentation of any fermented product you might imagine, like bread, yogurt, kvass, kimchi, sauerkraut. Worth the read!

Don’t say over-fermented

This is a wrong expression that I have also wrongly be using on many occasions like many others. You cannot over-ferment something. The difference on whether good or bad flavours will be produced in a food depends on the environment and microorganisms growing in it.

If desirable microorganisms are growing, like lactic acid bacteria for coffee fermentation, the result will lead to a clean cup. When this fermentation is ready to come to an end because all the lactic acid bacteria food will have been consumed by that microorganism, it should be the point at which a producer should start controlling with utmost care to follow on to clean the coffee and dry it.

If care is not taken of the time, temperature, humidity, other microorganisms can overpower the desirable ones, like acetic bacteria in coffee fermentation that will produce the unpleasant vinegary flavours.

It’s all about the perfect conditions for the desirable microorganisms to grow in!

So it is the same when speaking about our gut. If you take good care of your nutrition and don’t put trash in your body, only good microorganisms should be growing in your intestine producing vitamins, digesting food and bringing you wellness. Take care of yourself!


Graduate in Gastronomic Sciences, Q Arabica Grader, WSET L2 in wine. Obsessed with cooking new recipes, I love visiting producers and travel for food!

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