What Are the Two Main Types of Fermentation?

For many people, there exists much mystery around fermentation, the process, what it requires, and what the end result is. It may surprise most people to know that there are only two main types of fermentation, and that, when it comes to most fermentation industries, there is really only one.

So, what are the two main types of fermentation?

Let’s start with the fermentation process in general.

What Is Fermentation?

First, when most lay people around the world think about fermentation, they typically think about fermented foods – sauerkraut, pickles, kimchi, even yogurt.

Others may go so far as to know that kombucha is a product of fermentation.

But few understand that fermentation is also taking place in beer, wine, and all other alcoholic beverages.

How can this be possible?

How can fermentation produce yogurt and vodka?

Well, the precise definition of fermentation according to the Encyclopedia Brittanica is “a chemical breakdown of a substance by bacteria, yeast, or other microorganisms, typically involving effervescence and the giving off of heat.”

Basically, a teeny tiny living organism feeds on a substance and converts that substance to something else, usually something even more useful.

Grain is fermented to make beer or liquor.

Grape juice is fermented to make wine.

Tea is fermented to make kombucha.

Cabbage is fermented to make sauerkraut.

Milk is fermented to make yogurt.

In each of these scenarios, the end product often offers many more health and nutrition benefits than the original substance, including condensed and broken-down nutrients, probiotics, and more.

Two Types of Fermentation

The two main types of fermentation are a result of the two widest spread microscopic living organisms on the planet – bacteria and yeast.

Bacteria is the oldest known life form on earth, thought to be approximately 3.5 billion years old. It is a member of a large group of unicellular microorganisms which have cell walls but lack an organized nucleus. Bacteria is tiny, invisible to the human eye, and are virtually everywhere at all times.

Test Your Yeast


Bacteria can grow in the harshest conditions and when it cannot grow, it can lie dormant for millions of years, frozen in place, waiting to wake up and get back to work.

The job of bacteria is to break things down, and most bacteria, contrary to common belief, are good for us.

They help us digest food, they fight disease causing cells, and they give our bodies vitamins.

In fact, good bacteria will fight off bad bacteria and viruses in our bodies.

One of the many functions of bacteria on earth is lactic acid fermentation.

Yeast is also a tiny, microscopic, living organism, which is a member of the fungus family, the oldest living organism on earth. So, bacteria are the oldest life form, but fungus is the oldest living organism.

As a living organism, yeast is also unicellular, but it has its own nucleus. It is significantly larger than bacteria, so while there is less yeast than bacteria, yeast actually takes us more space on earth.

Yeast is also known to survive and thrive under pretty extreme circumstances, lying dormant during times of stress, and going into deep freeze when conditions get too cold.

We also have yeast in our bodies that serves the purpose of keeping our digestive system healthy and in balance. It supports our immune systems and works with bacteria to keep our guts healthy.

Yeast is also solely responsible for alcohol fermentation.

Lactic Acid Fermentation

Lactic acid fermentation occurs when bacteria are introduced to sugars in foods. The bacteria get in, break down the sugars, and produces lactic acid, which is an excellent source of probiotics for human health.

Fermented Foods

Some of the healthiest foods for humans are fermented dairy, sauerkraut, kimchi, and other fermented foods.

Further, the good bacteria that ferment, kill off the bad bacteria that can make us sick and even kill us. They do this both in the food and beverages they ferment and within our own body.

It has been found that often the best treatment for a bad bacterial infection is the introduction of good bacteria. And a gut rich with good bacteria will even prevent bacterial infections, disease, and chronic illness.

The Human Body

Lactic acid fermentation is also a process that takes place within the human body when we need energy but don’t have enough oxygen.

Typically, we get our energy when we breathe – aerobic cellular respiration takes place all day – as we breathe, carbohydrates in our body are converted to ATP to provide us with all the energy we need.

But when we put our bodies under extreme stress – running, lifting weights, or anything else that shortens our breath – and we are not providing our bodies with enough oxygen, our bodies switch into lactic acid fermentation – the muscle cells call for energy, and lactic acid fermentation kicks in and provides the ATP necessary, and much more quickly than regular aerobic cellular respiration.

Alcohol Fermentation

Alcohol fermentation is created by yeast.

The only ingredient necessary is sugar.

So brewers create a vessel filled with sugary grain wort, winemakers crush grapes in a large barrel, or ethanol producers crush and boil corn, and the sugars in those liquids settle in. The yeast in the atmosphere senses the sugar and is naturally attracted.

Of course, bacteria is also often attracted to those sugars, which is why many beers and wine from times past also contained good bacteria, which created a souring effect.

Today, of course, most alcohol producers keep their worts and musts in an airtight container to prevent cunicelontamination from unwanted yeast or bacteria and simply add their own yeast and potentially bacteria. Fermenting in this way allows for more control over the end product, of course.


Passionate about the fermentation process? So are we! If you’re interested in finding out how you can use our technology to control fermentation and monitor your yeast, save work hours and improve the cost-efficiency of your business, drop us a line at [email protected] or check out our product pages:

Also, you can now get access to a fully functional demo account to test our Web App. Completely free of charge and with no commitment to purchase.


  1. https://www.britannica.com/science/fermentation
  2. https://bio.libretexts.org/Bookshelves/Human_Biology/Book%3A_Human_Biology_(Wakim_and_Grewal)/05%3A_Cells/5.10%3A_Fermentation
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