Everything You Need to Know About Fermentation


Whether it be a pint of beer or a serving of Greek yogurt, fermented foods are all around us. But why are these products so beneficial - or on the contrary, irritating - to our systems? Let’s dig into the details. 

What is fermentation? 

In its simplest definition, fermentation is an ancient technique used to transform and preserve food. Typically the process yields a product that is different or more complex than the starting point. For instance, milk can be combined with certain yeasts and probiotic strains to produce kefir or yogurt; the end product post-fermentation is completely unique and rich in beneficial prebiotics and probiotics. 

What happens during fermentation? 

During the fermentation process, probiotic organisms transform sugar or starch molecules and break them down into simpler compounds in the absence of oxygen. This produces beneficial byproducts that did not previously exist in the food, like amino acids and enzymes.   

There are three common types of fermentation: lactic acid fermentation, ethanol (or alcohol) fermentation, and acetic acid fermentation. 

Lactic acid fermentation. Probiotic organisms break down sugar or starches, producing lactic acid which can protect foods from spoiling. This is the go-to fermentation for foods like yogurt or sauerkraut. 

Ethanol fermentation. Yeasts break down compounds called pyruvate molecules and transform them into alcohol to produce products like beer, wine, tasty sourdough bread. 

Acetic acid fermentation. Sugars in grain or fruit are transformed into sour-flavored products like apple cider vinegar.1 

What are the health benefits of fermented foods? 

With gut health being directly tied to overall wellness, incorporating foods that are naturally rich in prebiotics and probiotics can be a win-win for your system. The catalysts that make fermented foods so beneficial are many, but recent research has put a focus on both the byproducts or nutrients created during fermentation as well as the probiotic strains that create them. For instance, certain lactic acid bacteria (LAB) produce active peptides and enzymes that are renowned for their ability to support health benefits such as maintaining healthy blood pressure and fortifying the gut’s lining. 

As a whole, fermented foods can provide a host of antioxidant, microbial-balancing, and digestive-soothing benefits.2

When should you avoid fermented foods? 

If there’s anything we’ve learned, it’s that not all foods are for everyone. One person’s superfood could be another’s kryptonite. Fermented foods are no exception. Eating such a nutrient-rich food could require you to ease in; sometimes diving into fermented food without easing in could lead to uncomfortable bloating or gas. Also, if you have a food intolerance for cabbage, kimchi might not be the best option for your unique gut microbiome. As a starting point, lean into personalized nutrition with precision health and testing insights that can help you determine if a food is right for you.  

In addition to adjusting to fermented foods and food sensitivities, some people may have something called FODMAP sensitivity. FODMAPS refer to short-chain carbohydrates like lactose or fructose that can spark irritation in some people during digestion. Fermented foods like kombucha, kimchi, and sauerkraut contain FODMAPs and should be introduced steadily into the diet to see how you feel.3

What foods are commonly fermented? 

There are hundreds of food products available today that incorporate fermented foods. Like we mentioned above, most of us have, at some point, had fermented food sitting in our refrigerator. Here are three common fermented foods and the benefits they can bring.  

Kefir: Dairy products can be hit or miss for a lot of people. If compatible with your gut microbiome, kefir can be a viable alternative as studies show it could help ease lactose digestion in certain subjects. 

Flavor profile: Tangy

Benefits: Could help support bone health and promote smoother digestion. 

Tempeh: With a “cake-like” texture, tempeh is what happens when you ferment compacted soybeans. Studies show that increasing your soybean intake could result in lower cholesterol.

Flavor profile: Hearty

Benefits: Helps support cardiovascular health 

Kimchi: A popular Korean side, kimchi is typically made from fermented cabbage. Perfect for the spice-lovers out there, studies show that kimchi may help support healthy insulin and blood sugar levels.

Flavor profile: Spicy

Benefits: Supports healthy cholesterol and insulin levels.4 


Jar Your Summer 

Ever heard of the second summer? It’s the act of jarring or canning after the summer harvest, so you can enjoy beneficial foods long after the season is over. For the adventurous eaters out there, try your hand with at-home fermentation and do just that! 


  1. Tay, A. (n.d.). The science of Fermentation. Lab Manager. Retrieved September 1, 2022, from

  2. AC, Ş. N. G. B. B. S. (n.d.). Health benefits of fermented foods. Critical reviews in food science and nutrition. Retrieved September 1, 2022, from 

  3. Isadora Baum, Isadora Baum, & Baum, I. (2020, January 24). 5 possible reasons why gut-friendly foods make your stomach feel like Garbage. Well+Good. Retrieved September 1, 2022, from

  4. Link, R. (2017, October 18). 8 fermented foods and drinks you should try, from kefir to Kimchi. Healthline. Retrieved September 1, 2022, from