Wednesday, February 16, 2011

Get Over Fear of Bacteria: Fermentation Primer

Fun with fungi and bacteria. 
In my last post I mentioned how I had been experimenting with some home fermentation techniques. Well it took a little while, but the ball is really rolling on this now. I just tried a bottle of the latest elixir... Wow! It inspired me to sit down and type this out right now.

Some gooood stuff. 
Here's a brief explanation of  what fermentation is, its history, and benefits.

What is fermentation?
Fermentation is when microorganisms eat a carbohydrate, usually sugar, and release byproducts such as ethanol, lactic acid, and carbon dioxide. Basically you feed bacteria or yeast (fungi) sugar and they produce copious amounts of alcohol, CO2, and lactic acid. This results in a well preserved and usually bubbly (and sometimes alcoholic) food or drink. Think of fermentation as bacteria predigesting food to make nutrients more available for absorption.

History of fermentation.
Fermentation has been occurring in nature for longer than humans have been on the planet; in fact it's a vital process in the cycling of nutrients through the food chain that makes life possible.

The earliest evidence of humans controlling the fermentation process is wine-making about 8,000 years ago in the country of Georgia [1].

The first alcoholic society. Just kidding.
Iran, Babylon, Egypt, Sudan, and Mexico all were using fermentation techniques thousands of years ago and nearly every indigenous culture has developed some type of fermentation techniques. But why is it that fermentation has been sought out by so many different societies?

What kinds of food are fermented?
Here's a small sampling of foods that are dependent on the action of bacteria and yeasts.
  • Alcoholic beverages: Wine, Beer, Liquors, Mead
  • Lacto-fermented vegetables: Sauerkraut, Kimchi
  • Fermented dairy products: Yogurt, kefir, cultured milk, cheese
  • Bread: Such as sourdough (CO2 gas from bacteria causes bread to rise)
  • Fermented teas: Kombucha
  • Water kefir
  • Beet/bread kvass
  • Fermented soy: Miso and tempeh
  • Cured meats: sausages, salami, etc.
  • Other meats: rotten fish in the ground (yum!)
  • Poi - fermented Taro root
  • Fermented cassava
  • Many types of fermented grains and legumes.

Benefits of fermentation.
Although there are probably a lot of things I'm missing, fermentation seems to be generally used for these reasons:
  1. Adds a diversity of textures, flavors, and smells to foods.
    • Fermented foods taste awesome, but are definitely an acquired taste. 
  2. Preserving foods to last a long time without refrigeration.
    • Using bacteria or yeasts to convert carbohydrates in to alcohol, lactic acid, and acetic acid dramatically increase the amount of time that foods can go without spoiling. Before refrigerators, this is what everyone had to use.
    • For example lacto-fermentation creates lactic acid, a natural preservative that inhibits the growth of putrefying bacteria. 
  3. Improves nutrients available in foods.
    • Fermentation dramatically increases the availability of nutrients such as vitamins, minerals, and amino acids through a variety of mechanisms. Bacteria predigest foods and make them available for us to absorb. This really deserves an article of its own.
    • Fermentation creates Vitamin K2, an extremely important nutrient that nearly everyone is deficient in.
  4. Gets rid of anti-nutrients.
    • Double star this one- this is really important. A main part of ancestral nutrition is to not eat the anti-nutrients that are present in grains and legumes such as phytic acid, lectins, and other proteins. 
    • Fermentation breaks down phytic acid, destroys lectins, and can eliminate other problematic proteins. This is why it's so important to properly prepare grains and legumes if you are going to eat them.
  5. Decreases cooking time and uses less fuel.
    • This isn't so important in the modern world, but if you had limited amount of time and fuel this could be a big benefit. 
  6. Indirect benefits- Probiotic Bacteria:
    • Double star this one too, probiotic bacteria deserve an article of their own. In short, humans depend on the bacteria in our guts for a huge range of physiologic functions. With our industrial diets, good bacteria are often forced out and putrefying bacteria take over the gut which leads to a wide variety of nasty problems. 
So here's what some experts say on fermented foods:

Chris Kresser - The Healthy Skeptic:

"Almost all healthy, traditional cultures that have been studied regularly consume fermented foods like yogurt, kefir, sauerkraut, kim chi and kombucha. These foods have numerous health benefits, but in the context of heart disease one of the most important reasons to include them in the diet is that they are one of the few dietary sources of vitamin K2.  
...A 1993 study showed that those in the highest third of vitamin K2 intake were 52 percent less likely to develop severe calcification of the arteries, 41 percent less likely to develop heart disease, and 57 percent less likely to die from it."
"Probiotics found in fermented foods like yogurt, kefir, sauerkraut and kimchi strengthen and maintain the mucosal barrier system (in our respiratory and intestinal tract), which is our first line of defense against pathogens. What’s more, 75% of our immune system if found in the gut."
 Stephen Guyenet - Whole Health Source
"Healthy grain-based African cultures typically soaked, ground and fermented their grains before cooking, creating a sour porridge that's nutritionally superior to unfermented grains. The bran was removed from corn and millet during processing, if possible. Legumes were always soaked prior to cooking.

These traditional food processing techniques have a very important effect on grains and legumes that brings them closer in line with the "paleolithic" foods our bodies are designed to digest. They reduce or eliminate toxins such as lectins and tannins, greatly reduce anti-nutrients such as phytic acid and protease inhibitors, and improve vitamin content and amino acid profile. Fermentation is particularly effective in this regard. One has to wonder how long it took the first agriculturalists to discover fermentation, and whether poor food preparation techniques or the exclusion of animal foods could account for their poor health."
Good resources from Stephen:

Chris Masterjohn - The Daily Lipid
"Vitamin K2 is abundant in grass-fed animal fats and fermented foods, and promotes broad facial structure, healthy bones and teeth, a properly functioning nervous system, and robust cardiovascular health.
An accumulating body of research suggests that vitamin K2 may also protect against cancer."
 Robb Wolf - Paleo Solution
"The roles these bacteria play are varied, but they are critical in not only the digestive process, but also in actually protecting the gut lining. Our beneficial flora (the living mass of bacteria in our intestines) actually line the villi and microvilli in such a tight association that the bacteria are literally the first layer of our intestines. These bacteria displace potentially pathogenic bacteria, yeast,k and parasites; help us to digest macronutrients; and are responsible for production of various vitamins from precursor molecules.
...Most people are familiar with various fermented foods such as yogurt, kiefer, miso, kimchi, and raw sauerkraut. All of these foods (if not pasteurized) provide live cultures of beneficial bacteria."
Mark Sisson - Mark's Daily Apple

"[F]ermentation can render previously inedible or even dangerous foods edible and somewhat nutritious. The lectins, gluten, and phytates in grains, for example, can be greatly reduced by fermentation. I don’t advocate the consumption of bread, but if you’re going to treat yourself to any gluten grain-derived food, make real, long-fermented sourdough bread the one. The Romans managed to do okay on the stuff, but that’s only because meat was expensive and didn’t travel as well. Real sourdough is a good choice for guests who simply must have their bread, but don’t think fermentation makes it Primal approved.
Dairy is another beneficiary of fermentation. In fact, next to no dairy at all, I put fermented, raw, grass-fed dairy as the optimum form. The fermentation process breaks down the lactose, thus mitigating a potentially problematic sugar and decreasing the carb content (you can consider the official carb count of real yogurt cut in half; producers list the number of carbs present in the dairy before fermentation, and the fermentation process breaks down the lactose/sugar)." 

Wrap up.
Fermented foods is fun to make and has numerous health benefits. Stay tuned for part 2 where I'll show you what I've been making.

What kind of fermented foods do you like? Leave a comment with your thoughts.


  1. Awesome write-up Tyler. I was on a kefir stint for about a month, drinking a pint day until I started getting congested from the dairy. It would have been nice to preserve the grains, but instead I ate the little boogers.

  2. Right on, Danny.

    I've been thinking about trying some kefir and seeing what happens. I love dairy products but after much trial and error I have realized that they make me congested for a couple days, and make me break out with a slightly delayed effect. This breaks my heart because I love cream and yogurt...

    Latley I've been making water kefir and kefir beer which are both dairy free.

  3. U should post a how to on home fermentation

  4. I can do that... what kind of things are you interested in fermenting?

  5. Great article! Fermented products have their pros/cons def. I think they should be enjoyed in moderation as they are strongly linked to allergies.

  6. Hi HTDY-

    I hadn't heard about the allergy connection before. Could you point me in the direction of somewhere I could learn about this?


  7. Here's another good beginner's resource to make your own fermented foods

  8. Hi Tyler,

    Great information! Incidentally, a new study came out last year finding that children with celiac disease are more likely to be K2 deficient. Another good reason for celiacs to eat fermented foods!

  9. Tyler, this one is again very good information from you. Thanks for share the detail about that news.