What do vinegar, blue cheese, sauerkraut, and wine have in common? They are all fermented but they are not the same type of fermentation. For fermenting foods and beverages we can use bacteria, yeasts, molds, and other microorganisms. Each of those will produce a different type of food and beverage. The process of fermentation will also be different in flavors, acidity, and duration of the fermentation process.

So if you are feeling a little confused about what are you supposed to be using to start with your first fermentation recipe this little guide will make it more clear and concise. And if you are just trying to learn more about the world of fermented food and beverages you have come to the right place. There is another difference you need to learn What Is The Difference Between Pickling & Fermenting?

1. Lacto-Fermentation

A genetic strain of bacteria called Lactobacillus is responsible for Lacto fermentation. The bacteria feed on the glucose in the carbohydrates and sugars naturally occurring in foods. They convert glucose into lactic acid as a byproduct. It’s the lactic acid that gives Lacto fermentation that distinct tangy to sour flavor. Some of the most commonly known Lacto fermented foods include sauerkraut, kimchi, and yogurt.

This lactobacteria are commonly called probiotics, the bacteria that are good for our digestive system. They are naturally occurring in the environment including on vegetables and the soil. While many harmful microorganisms typically can’t survive without oxygen nor in a highly salty or acidic environment, lactobacillus can. They are salt and acid-tolerant while also anaerobic, meaning they don’t require oxygen. In the instance of fermenting vegetables, a saltwater solution is used called brine. The vegetables are submerged under this brine and as nature would have it this is a perfect design. Since the combination of no oxygen and salt contributes to an unhospitable environment for harmful pathogens.

While the lactobacteria are feeding and thriving they are also generating lactic acid which additionally acidifies the brine, again contributing to an inhospitable environment for harmful pathogens. Since lactobacillus naturally occurs in vegetables no starter culture is required. A saltwater solution brine is not mandatory for other Lacto fermentation mediums such as milk, seeds, and nuts used in making both dairy and nondairy yogurts and kefirs. All that’s needed to get a Lacto fermentation initiated with those mediums is a starter culture of lactobacillus strains. From there you can lacto ferment just about anything including water.

2. Alcohol Fermentation

Yeast is the microorganisms that ferment sugars into ethanol alcohol and carbon dioxide as byproducts. The alcohol element is what gives wine, beer, mead, and spirits their kick and carbon dioxide is the gas that can be seen as bubbles during the fermentation process. And later used to generate carbonation in a fermented beverage.

Alcohol fermentation can be overly simple to quite complex. The naturally occurring yeasts are what causes the spontaneous alcohol fermentation of damaged or over-ripe fruits and require no human intervention. On the flip side with human intervention the science and art of making specialty alcoholic beverages like beer and wine can be complex and precise.

3. Aceto-Fermentation

Vinegar is generated by a genus of bacteria called acetobacter. They are responsible for creating vinegar. What type of vinegar that produces depends on the medium used to start the process. Apple cider vinegar uses apples, wine vinegar uses grapes and rice vinegar uses rice.

Vinegar making is a two-phase process of fermentation. Phase one is fermenting the medium such as apples into an alcohol ferment, hard cider. This is the same type of alcohol fermentation where yeast consumes the available sugar and converts it into alcohol. Once the alcohol fermentation has commenced the yeast dies out due to having consumed the available sugar of the medium.

Next, come phase two aceto-fermentation. Acetobacter is naturally present in the air around us and is an aerobic microorganism, meaning they require oxygen. By exposing the commenced alcohol fermentation to the air the acetobacter begin doing their job by consuming the alcohol and generating acetic acid as a byproduct. Acetic acid is the primary constituent of vinegar other than water. And is the acetic acid that acidifies the vinegar, gives the sour taste, and generates flavors. The duration of the vinegar-making process from phase one through phase two is about 6 to 8 weeks.

4. Mold Fermentation

In modern western culture, mold is generally associated with food spoilage and it is avoided. However, not all mold is bad. Mold cultures have been traditionally derived from the environment for many centuries around the globe by nearly all societies. In the west the most familiar mold fermentations are cheeses. Asian cultures have many distinguishing mold ferments such as Japanese koji used to make sake, miso, soya sauce, and tempeh are also created using mold fermentations.

Molds of all kinds need oxygen, moisture, and warmth to grow. However for kinds of molds intended for fermentation processes they need each of those environmental conditions in balanced and controlled proportions. Different environmental niches give rise to different molds and their characteristics including flavor. Compared to other types of fermentations, molds have a reputation for being quite risky.

5. Symbiotic Fermentation

Many types of fermented foods either rely on or coexist in a symbiotic relationship. Other ways to describe a symbiotic fermentation is to say interdependent, collaborative, or combining. Essentially it’s where one type of fermentation can’t happen unless another type happens first, or more than one type of fermentation is happening at the same time. Kombucha, soy sauce, and sourdough are other foods that have a symbiotic fermentation relationship unique to themselves.