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Wild fermentation is synonymous with natural, spontaneous and indigenous fermentation. It means that the beneficial yeasts and bacteria which are naturally occurring on the food or drink are allowed to grow throughout the fermentation process. When put in the right environment the beneficial yeasts and bacteria dominate the culture preventing the growth of pathogenic or spoilage organisms. It is used in the production of all types of fermented foods like sauerkraut, pickles, vinegar, wine and beer. It may sound like an uncontrolled process but in fact it is highly controlled and scientific in nature. Each type of fermentation requires a different temperature, container, timeline and ingredients to be successful.
Three common types of wild fermentation
Yeast fermentations
Yeast cultures need simple sugars to multiply and grow quickly in a warm environment. Most yeast strains are not salt tolerant. They do not need oxygen to multiply but their respiration is more efficient in the presents of oxygen which produces less alcohol. These conditions have been taken advantage of by the alcohol production industry.
Alcoholic beverages and other alcoholic liquids are fermented in anaerobic conditions, mostly in warm conditions without the addition of salts. This is done whether the fermentation is wild or not. The difference being wild fermentation relies on naturally occurring yeasts rather than packaged yeasts developed for specific purposes.
Wild yeast fermentations found in the wine and beer industries are referred by the terms “natural” and “spontaneous” respectfully.
Natural wine is how wine was made for centuries. Although the term natural encompasses a wider meaning which includes growing grapes without the use of pesticides and chemical fertilizers and non-mechanized methods of harvesting.
Fermenting grapes naturally relies on the yeasts which are found on the grapes and in the environment. The process involves the crushing of grapes which helps the resident yeasts of the grapes to access the sugars found in the fruit. After a short period of exposure to oxygen the grapes are then pressed leaving the resident yeasts in the must. The must is then placed in air locked containers to limit the growth of unwanted bacteria like acidic acid bacteria (which will turn wine into vinegar).
Spontaneous fermentation of beer is done quite differently. The wart is made by boiling the ingredients to stratify the carbohydrates into simple sugars. The boiling also kills off the natural yeasts needed to convert the wart into beer. To encourage spontaneous fermentation in beer the wart is poured into wide and shallow vats which are exposed to the air of the brewery. The resident yeast cultures in the air are deposited into the wart which has a high sugar content. The yeasts quickly dominate the culture in the first few days of the fermentation. Once the rapid fermentation subsides it is filtered and placed into a secondary fermentation container with an air lock. This allows the yeast to consume the remaining sugars without competition with other bacterial cultures.
Lactic acid bacteria fermentations
To successfully ferment using wild lactic acid bacteria the environment needs to have a brine with a salt percentage of at least 2.5%, kept in a cool location not above 72 degrees and in an anaerobic environment.
Lactic acid bacteria fermentation is usually used for fermenting vegetables. A wide variety of fermented vegetables are made by the simple process of stuffing vegetables into a jar with salt and some type of liquid and then sealed to limit the oxygen in the container. Lactic acid bacteria do not need oxygen to live and they are salt tolerant so they can survive the brine made by the salt mixing with the liquid. Yeast and mold are not as salt tolerant so they cannot dominate the culture. Once the lactic acid has acidified the vegetables other cultures cannot get a foothold in the culture which further protects it from spoilage.
Sauerkraut is made by shredding cabbage, adding spices and salt and then jammed into a crock until the cabbage juice covers the shredded cabbage. It is then sealed in a variety of ways and left to ferment in cooler temperatures. Pickles are made using a salt brine rather than the cucumbers natural juices. The process is the same, stuff a container with cucumbers add the brine and cover.
Acidic acid bacteria fermentations
Acidic acid bacteria grow best when they have access to alcohol and oxygen. They are used to make vinegar from any type of alcohol including grape wine, beer and sake. They also will produce vinegar from any liquid which contains yeasts while exposed to the air.
Acidic acid bacteria are the culprits which turn wine into vinegar. They need oxygen to grow well which is why alcohol fermentation includes a period of fermentation in an anaerobic environment.
Acidic acid bacteria grow wherever there is access to oxygen.. Although they grow best with alcohol there are strains which can use sugar as well.
There are several ways to make vinegar which include simultaneous alcohol-acidic acid fermentation, pre-fermenting the liquid into alcohol then aeration of the liquid. Each method produces different flavors and characteristics of the vinegar.
Not all wild fermentations are limited to only one type of fermentation culture
If you have ever made sourdough you have used a culture which has all three of these cultures in it. The yeasts in the sourdough starter are joined by lactic acid bacteria and acidic acid bacteria which when mixed with fresh flour act on the sugar in the mixture to produce CO2. The CO2 gets caught in the dough causing it to rise.
Kombucha can also be wild fermented by acidifying a batch of sweet tea and placing it in a warm location. The liquid will become a breeding ground for yeast and lactic acid. Once the yeast starts to produce alcohol acidic acid bacteria will also start to grow.
Ginger bug is another wild fermentation which is dominated by yeast and lactic acid bacteria. Made by adding chopped ginger water and sugar to a jar the yeasts and lactic acid bacteria quickly dominate the mixture and prevent spoilage cultures from getting a foothold.
Fermentation will happen
Let’s be clear. Fermentation is not something which we invented, developed or fully understand. It is a natural process which breaks down organic material into simpler forms. It is God’s recycling program. We have just learned how to control the conditions of the fermentation to produce a wide variety of foods and drinks.
Wild fermentation is how these products were developed and made through the centuries. Although not all fermented products are made today through wild fermentation they all have their roots in a spontaneous event where some useful microorganism ended up in a food product and produced something good. Once it was discoverd that using some of the new fermentation to start another batch worked the process of backpropagation and selection began.
This is where cultures which fit a certain criteria are used to start the next batch, environmental conditions and length of time are considered to control the outcome. The method of using one culture to start another is called backslopping. This method has been taken to the extreme with the development of packaged starter cultures. These starter cultures are grown in ideal conditions for specific uses such as bread yeast, wine yeast, even mold cultures in the case of Japanese koji, but they all started with a wild fermentation.
Not all fermentations can or should be made using wild fermentation
Some fermentations undergo several steps to be successful and must be treated correctly to get a specific result. These include making any fermentation using koji like saki, soy sauce and miso. Tempeh also needs a specific mushroom culture to produce the wanted flavors and health benefits.
Another culture specific product is cheese. Cheese is made from a variety of milks and cultures, fermented at different temperatures and times and with different starter cultures. All these variations produce an unlimited number of different cheeses. If they were wild fermented the end product would be unpredictable, not bad or unhealthy just unpredictable. Therefore to control whether cheddar or blue cheese is made the conditions are controlled including the culture which is introduced at the correct time and temperature.
Natto is another fermentation which had its roots in wild fermentation when boiled soybeans were packaged in straw. Providing an ideal environment for the bacterial culture Bacillus subtilus which is naturally found on grass throughout the world to grow. The beans were consumed and found to be healthy and appealing.
Why you should try wild fermentation
Just like modern fermentation methods wild fermentation is not dangerous or risky when the proper methods are used. It can be done with a minimum of equipment with a wide variety of mediums. You can make alcohol, preserve vegetables, produce healthy drinks and above all add to the variety of bacterial cultures in your gut.
Wild fermentation produces some of the best tasting products. Adding depth of flavors to alcoholic drinks, vegetable preserves and non-alcoholic drinks which cannot be duplicated using modern methods.
So give it a try. It is easy, healthy and delicious.