Sourdough bread, sauerkraut, fermented cheese, and quality wine. In addition to the rich taste and health benefits, these things have something else in common - fermentation.
The fermentation of food is an ancient process that humans have used since before we understood the scientific background of this process. The process of fermentation is known almost everywhere in the world. In most cases, people ferment drink and food which has a very important place in the culinary culture of a specific nation or region.
WHAT IS FERMENTATION
In short, fermentation can be described as a chemical process in which the activity of microorganisms produces desired changes in taste, preservation, or health effects.
To simplify, fermentation occurs with the absence of oxygen and in the presence of beneficial microorganisms (yeast, mold, bacteria) which convert into alcohol and/or acid with the help of sugars and starch in the food. This makes food and drink more nutritious and extends its durability.
The fermentation produces enzymes necessary for digestion and this is of the utmost importance because humans are born with a limited amount of those enzymes and these also decrease over the years. However, the fermentation helps in the pre-digestion itself because microbes which feed on sugars and starch thus accelerate the degradation process which begins before the consumption itself.
ADVANTAGES OF FERMENTED FOODS
Fermented products are rich in probiotics, useful microorganisms that help maintain a healthy intestine do its job – extracting nutrients from food. Probiotics help the immune system because our intestine produces antibiotics, anti-tumor, anti-viral, and anti-fungal substances - and pathogens do not like the acidic environment created by fermented food.
Fermentation also helps neutralize anti-nutrients such as phytic acid, most commonly found in grains, nuts, seeds, and legumes and it inhibits the absorption of minerals. The phytic acid also makes starch, proteins, and fats less digestible and its neutralization is extremely important. Fermentation can increase the content of vitamins and minerals in food and makes them more accessible for absorption.
TYPES OF FERMENTATION
We distinguish between three typical fermentation types:
Lactic acid fermentation. This process is triggered by lactic acid bacteria. For example, sauerkraut is induced by Leuconostoc Mesenteroides, which only slightly increases the acidity level of the saline (0,3%). As the acidity of the solution increases, these bacteria die, and Lactobacillus Plantarum bacteria activate which raise acidity levels up to 2%. No thermal treatment is required for the lactic acid fermentation process and the temperatures applied are between 15 and 22 °C. In addition to lactic acid, which prevents the growth of acid-sensitive organisms, lactic acid bacteria also form a substance that prevents the growth of mold and substances with bactericidal properties. Examples of lactic fermentation are sour bread, sauerkraut, pickles, kimchi, and yogurt.
Alcohol fermentation. Ethanol fermentation is a biological process most easily described as the transformation of the sugars (such as glucose, fructose, and sucrose) to ethanol and carbon dioxide. The process takes place in the cells of micro-organisms, yeasts, and some bacteria. This is a complex process that contains a variety of biochemical reactions. A number of different types of yeast are involved throughout the whole process, which is divided into a latent phase, exponential growth phase, quasi-stationary phase, and death phase. Wine and beer, for example.
Acetic acid fermentation. This fermentation must already meet the conditions of alcoholic fermentation. Unlike the fermentation types mentioned above, acetic acid fermentation requires oxygen and slightly higher temperatures (between 25 and 28 °C). For this type of fermentation, you can use the starter culture (sponge) and it can be also successful (only a little longer) without it. Example: wine vinegar, apple cider vinegar, kombucha.
HOW TO START
With some fermentations you will need a starter culture: for kefir, you need kefir grains, for kombucha you need a symbiotic colony of bacteria and yeast (SCOBY), and for Japanese miso, you need koji bacteria. There are also some other starter cultures available on the market.
However, food can be acidified without the use of starter cultures, only with salt. Natural acidification without salt is also possible, but in this case, the food is softened. In addition to its consistency, the salt also adds flavor and prevents harmful bacteria, that are not suited to the salty environment, from developing. At the same time, it produces a bloom of beneficial lactic acid bacteria of the genus Lactobacillus.
The general rule for fermentation is 2% salt per kg of vegetables (20 g) and 2% saline (20 g per 1 l of water) for fermenters where you need to add liquid. Foods with all spices must be completely covered in liquid at the fermentation stage, as it may cause mold growth on the floating pieces, which may corrupt the entire contents of the jar. This is why it is recommended to add the spices to the bottom of the jar so they don't float to the top.
Vegetables (or fruit) you want to ferment should be fresh and organic. In non-organic vegetables, which have been stored for a long time, solutions that maintain a good appearance are often used, thereby destroying naturally occurring bacteria.
WHAT TO FERMENT
We can ferment almost every fruit and vegetable. This way you can preserve food for winter, you can make sauces, salads, drinks, or improve already prepared meals.
We know a number of traditional fermented foods, and let me just name a few of the most famous and delicious dishes: