Bar fermentation: basic concepts and applications | Giovanni Ceccarelli

Bar fermentation: basic concepts and applications

Lately, we often hear about fermentation and fermented foods, including drinks, which are of great interest to many chefs and bartenders. Actually, fermented foods are part of our gastronomic culture since a long time but we have lost their use mainly due to, or thanks, to the advent of the domestic refrigerator and industrial production that, sterilizing containers and foods, avoids the presence and proliferation of any microorganism. In fact, fermentation was mainly used as a method of conservation.

In the last few years there has been a rediscovery of fermentation and fermented foods. The reasons are manifold and mostly related to the will to break away from mass production, in the wake of all the movements related to environmental sustainability, farm-to-table and similar.

The fermented product is seen as something crafted, home-made and therefore of superior quality.


But actually what does it mean that a food is fermented? And above all, what has changed in it?

Fermented foods are foods that have undergone a series of transformations mainly due to bacteria and yeasts, which have altered the chemical composition of the foods and the liquid medium in which they are immersed.

These transformations have 3 major consequences:

  • They allow you to preserve medium to long term foods. Think of cheese, salami and pickled vegetables: all fermented to allow preservation. The fridge and the supermarket have not always been part of our daily life;
  • They develop several compounds that partly change the flavour of foods;
  • They change the availability of some substances in foods, improving their nutrition and health. This is not an aspect that we will deepen in this blog because we believe it is not inherent in the mixology world.

All these transformations are possible thanks to the presence of “good” microorganisms that allow the desired organoleptic result and protect the fermented food from microorganisms that make it rot or worse make it dangerous for human health. “Good” microorganisms are not limited to carrying out their transformations but, changing some environmental parameters such as pH and producing some substances called bacteriocines, prevent “harmful” bacteria from proliferating.

From our point of view, the most important and interesting aspect of fermentation in bartending and cooking is the second: a technique to obtain different and unique flavours. Fermentation leads to a greater variety of molecules present, increasing the aromatic complexity of the food that has been fermented, and thus allowing for unique results.

Fermentation is a formidable tool in the hands of those barman and chef who want to distinguish.

Now that we understand what it takes to ferment, let’s try to give it a more technical definition.

Fermentation is a biochemical process under anaerobic conditions (absence of oxygen), that takes place in several microorganisms, mainly bacteria and yeasts, which use sugars and other substances present in food to produce energy, that is, to live. However, this “biochemical” definition confines us to the world of the absence of oxygen, excluding certain processes involving specific bacteria that need oxygen to happen, such as in vinegar production.

From now on, we will broaden the definition of fermentation to all food processes performed by microorganisms, regardless of whether they occur in presence or absence of oxygen. This is a small linguistic freedom that we take to simplify and avoid using unnecessarily too many scientific terms.

In general, bacteria and yeasts fermenting foods are called ferments, but this term can be extended to enzymes that microorganisms use in biochemical processes, that are proteins specializing in the transformation of certain molecules. Often, individual enzymes are isolated by humans and used to achieve a specific result without the implementation of microorganisms.

How many types of fermentation exist?

Depending on the microorganisms involved in fermentation and final products, we will have different types of fermentation, which take the name from the most important substance produced at the end of the process. The two types of fermentation that most interest us are lactic fermentation and alcoholic fermentation. There is also acetic fermentation, but we will treat it individually.

Lactic fermentation will mainly produce lactic acid, while alcoholic fermentation will produce alcohol (mainly ethanol). In both fermentations, there is a production of CO2.

Even within the single lactic or alcoholic fermentation we can have different results and flavours, depending on the most present microorganisms.

But how do we make this or that fermentation happen?

As we said, fermentation is a process carried on by some microorganisms. So, if we want a specific type of fermentation to take place, we will have to make sure that the particular microorganism that causes the desired process is more present.

To do this, there are two ways: either to create optimal conditions for that kind of microorganism at the expense of others or to inoculate that exact bacterium or yeast in a massive manner.

The first method takes the name of wild fermentation. To achieve wild fermentation, it is necessary to create the ideal conditions for proliferating only the desired microorganisms already present in the environment (yep, microorganisms are everywhere even if we do not see them!), so that they have an advantage in proliferating. Once given this advantage, they will take care of making the environment more suitable for their proliferation and inhospitable for all other microorganisms.

With the second method, the same result is obtained but the desired microorganisms are inoculated in bulk. This will give them an initial numeric advantage that will allow them to change the environmental conditions to their advantage. These selected bacteria or yeasts are named starter.

Now that we know what fermentation means and the main aspects, we can deepen the individual fermentation processes in the future by applying them to some preparations.

I wish you a good fermentation!

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