THE 3 TYPES OF FERMENTATION: ALCOHOLIC, LACTIC AND ACETIC

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There are numerous types of fermentation, the main ones being the alcoholic, lactic and acetic. We are talking about metabolic processes that take place in the absence of oxygen, where glucose is degraded into other organic compounds. Normally these processes take place through bacteria and yeasts, and are widely used in the industrial field for the production of beverages and foods such beer, wine, vinegar, yogurt and fermented foods.

ALCOHOLIC FERMENTATION

In this natural biological process, sugars such as glucose, fructose and sucrose, are converted into cellular energy by yeasts when placed in an oxygen-free environment, the microorganisms also produce ethanol (alcohol) and carbon dioxide as their metabolic by-products.

Rum is produced from the fermentation of sugar cane and whiskey, vodka and beers are produced from the fermentation of wheat. Alcoholic fermentation produce ethanol which, acting as a germicide, allows for longer conservation.

Let’s take some examples. In the case of beer, fermentation transforms maltose and sucrose into ethanol and carbon dioxide which will make the beer sparkling. The alcoholic fermentation that occurs instead for the wine transforms the fructose present in the grapes into ethanol and CO2. In the case of bread, the starch is transformed into ethanol (which evaporates during cooking) and CO2 which will allow it to rise.

LACTIC FERMENTATION

It allows the production of acidic foods such as yogurt, where lactobacilli are used. This fermentation also takes place in the absence of oxygen and glucose is converted into lactic acid. Lactic acid fermentation occurs when bacteria convert the sugars present in food into cellular energy and lactate, or lactic acid. Lactic acid is a natural preservative that inhibits food spoilage.

Examples of vegetable lactic acid fermentation include sauerkraut, olives, kimchi, kefir, yogurt, soy milk, cheese and tofu.

ACETIC FERMENTATION

This fermentation takes place in the presence of oxygen, and allows the ethanol contained in alcoholic beverages and foods such as fruit, vegetables and cereals to be transformed into acetic acid. This process is carried out by acetic bacteria, and is fundamental in the production of vinegar.

This type of fermentation process occurs when ethanol is exposed to oxygen. Vinegar is produced by a group of bacteria known as aceto-bacter, which convert alcohol into acetic acid or vinegar. If you’ve ever left a bottle of wine open for too long, you’ve probably experienced this type of fermentation.

Examples of acetic acid fermentation include apple cider vinegar, wine vinegar, coconut water vinegar. The production of acetic acid extends storage even beyond that of ethanol. Depending on the quantity, acetic acid can inhibit the reproduction of pathogenic bacteria or even kill them completely. This is why vinegar is such a common commercial condiment for pickling and preserving vegetables.

FERMENTATION BASICS

1. Begin with small productions
Start with small and manageable projects, become familiar with it, then expand your brewing projects. Fermenting food is an all-round enjoyable experience, can be done with family, friends, or find some fermenting colleagues to expand your horizons with. There are ideal productions for those who start as for Greek-style low-fat yogurt, sauerkraut, kimchi, and various sauces. You may want to consider making natural sodas, even if they require specific starter cultures, such as basic Kefir or Kombucha.

2. Expectations
After the first initial successes, you will be more and more tempted to take on new projects. Try to be realistic about your and space available. Determine the number of jars and other fermentation vessels you are able to handle. Design your pantry the best as possible, considering that some items will need to be kept at room temperature, others in the refrigerator. In no time, you may handle several fermentation simultaneously. The list of options is limited only to the space available, time and imagination.

3. Planning and preparation
The fermentation of certain foods involves ordering special equipment or supplies, so consider these times in your schedule. Fermentation may require a variable time commitment depending on the type of fermentation undertaken. Make a realistic work plan and familiarize yourself with techniques you are yet unfamiliar with.

4. Sanitize
When you use the kitchen at home, it’s essential to keep the environment where you are going to work scrupulously clean. Although the fermentation process includes bacteria, these must be of the right type! An adequately clean environment allows to reduce the possibility of interference and external contamination in the preparations you are going to make.
• Sanitize your workplace simply with a solution of water and distilled vinegar as an antibacterial agent.
• All the equipment used must be disinfected, rinsed and air dried before use. You can wash your glass containers with hot soapy water and rinse with a solution of water and vinegar. Leave to air dry.
• Even the equipment used exclusively for fermentation must always be disinfected, rinsed and air dried before being used and stored. If possible, keep everything in one container.
• Washing your hands thoroughly with an odorless bar of soap before starting and after handling food or other non-sterile items is essential.
• Do not prepare different categories of food on the same work surface. To avoid the risk of cross-contamination, try to focus on one fermentation category during each session, and if possible avoid cooking other foods in the same place where you handle fermentation.
• Bring some paper towels and a small bin for garbage, a second bin for your utensils, and a couple of cotton kitchen towels to dry your hands while you work.

5. Take notes
Record your observations along with your results so that you can draw on that information for your future brews. Each experience will enrich you and help you to master this art more and more!

THE BRINE

Vegetables in particular ferment best under the protection of brine. Brine is simply water with some salt dissolved in it. In some fermented products, such as sauerkraut, the salt is used to draw water from the cabbage, the vegetable juice becomes an intense brine.

The brine acts as a protection against the growth of unwanted microorganisms, promoting the growth of the desired bacterial strains, the lactobacilli. The amount of salt used in the brine can vary according to the preparations and personal tastes. The more salt you use, the more acidic and slower the resulting fermentation will be. With too much salt, however, no microorganisms can survive, and fermentation will not take place.

Another “guarantee” for rapid and optimal fermentation is the use of whey. This serum allows us to introduce live enzymes to our vegetable fermentation. Usually a couple of tablespoons of whey are always added to the preparation when possible. Whey is easily extracted from yogurt and kefir, draining through a cloth to separate the solid mass from the whey. We can keep whey for over a month in the refrigerator.

Once you’ve filled your crock with the ingredients you want to ferment, find a lid that fits inside. To prevent the vegetables from floating upwards, where exposure to air would cause them to mold, you need a cover and a weight.
For a weight, I usually use a 2-liter glass bottle full of water, rather than a stone sterilized in boiling water.
Another method I sometimes use is to ferment vegetables in a wide-mouthed jar, is using a smaller jar with a weight tucked into it. Even if there is some space left between the walls of the cans it would not be a problem. You can always cover everything with a tea towel or coffee filter to keep out insects and dust.

FERMENTATION AND PROBIOTICS

A healthy and thriving digestive system is full of these good bacteria that positively affect our immune system, our mental health and our digestion. Many factors can alter the ideal balance of good intestinal bacteria. Stress, processed foods, antibiotics, a lack of fiber (especially green leafy vegetables), and poor sleep habits damage the gut microbiota.
Buying fermented foods is an option. Unfortunately many of those fermented foods on the market are pasteurized, and don’t contain probiotics. The cheapest and most effective option for having foods rich in probiotics is home fermentation.
Sauerkraut is probably the simplest food to prepare. Cabbages are relatively cheap, easily available and don’t need any starters to ferment.

Here a simple recipe to prepare delicious sauerkraut, you will only need three ingredients:  cabbage, some sea salt and a container!