ANCESTRAL EATING: Five Easy Fermentation Recipes

Ease yourself into the wonderful world of external digestion with these delicious recipes

Welcome back, boys and girls, to another edition of ANCESTRAL EATING. The theme has been fermentation recently: we’ve looked at what fermentation is and does; we’ve made a simple sourdough starter; and we’ve used that simple starter to bake a basic einkorn loaf that resembles the kind of bread your ancestors would have eaten (if your ancestors ate bread, of course).

In this instalment, I’m going to give you five simple recipes to make delicious fermented foods. You’ll learn how to make sauerkraut; oat kissel; kvass; Tabasco; and a simple sour drink (kumis) from raw milk. How cool is that? Very.

Note that you don’t need any complicated apparatus to make fermented foods: just some jars with lids. Kilner jars look cool and are very fashionable (see pic above), but just plain old jars will do. Fermentation weights will also help, but they’re not strictly necessary.

Also: filtered water is best for all of these recipes, if you have access to it. It contains less chlorine and other nasty stuff that might retard the fermentation process.

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Before we get on to the recipes, let’s just have a quick recap about fermentation. On Thursday, I wrote about a new study which claims that fermentation may have had a key role to play in human evolution, allowing our ancestors to grow bigger brains by shrinking their digestive apparatus. Fermentation could have allowed this to happen by allowing circulating microbes to kick off the digestion process outside the body (“external fermentation”), meaning that our ancestors could absorb more nutrients from a smaller gut.

It’s worth emphasising again that fermentation — processes of chemical transformation of a substrate (i.e. food) — can take place anywhere, whether inside or outside the body. When you let microbes sour cabbage in a jar, this is a process that is little different from what happens inside your gut or the gut of a chimpanzee or giraffe.

Here’s a nice explanation, from the new study, which outlines the benefits of external fermentation.

Rather than relying on the microorganisms within the gut, external fermentation is carried out by organisms in the environment or on the surface of the organic material itself. Like internal fermentation, external fermentation increases the bioavailability of ingested nutrients, specifically, the absorption of macronutrients and micronutrients. In addition, external fermentation contributes to the health and efficacy of the host’s gut microbiome, in turn, facilitating nutrient absorption. External fermentation enhances digestibility of carbohydrates and proteins. Fermentation of legumes hydrolyzes macromolecules into more easily digestible individual amino acids⁷³ and sugars⁷⁴. These benefits have led public health scholars to recommend increasing the consumption of fermented foods in countries experiencing food insecurity and high infant mortality^75,76.

External fermentation also improves the bioavailability of micronutrients in a number of ways. B-complex vitamins produced from the external fermentation of carbohydrates can increase the amounts of B vitamins (thiamin, riboflavin, and niacin) by up to 10-fold^77,78. External fermentation can also break down ANFs [anti-nutrient factors].

Phytate, a chelating ANF, can be broken down by phytase, an enzyme that some mammals—but not humans—have evolved the ability to produce endogenously⁷⁹. External Lactobacillus-driven fermentation is an alternative to phytase: by lowering the pH, it provides a favorable environment for both bacterial and endogenous phytase to hydrolyze bound phytate and release minerals⁸⁰. Oxalate, another chelating ANF, and tannins, ANFs which bind to and lower the bioavailability of proteins, can also be degraded through external Lactobacillus fermentations^81,82. Of note, phytate is more effectively degraded by external fermentation than by cooking, as phytase bioactivity decreases above 80 °C^83,84.

External fermentation can go further than simply increasing nutrient bioavailability. It can also render poisonous foods edible. One example is the detoxification of cyanogenic glycoside in bitter cassava (also known as yuca or manioc), a common staple for hundreds of millions of people living within the Tropical Belt^75,85. If consumed unfermented, cassava’s cyanogenic glycosides are hydrolyzed by colonic microorganisms and absorbed as cyanide, causing convulsions, hypotension, respiratory failure, decreased heart rate, and death^85,86. When processed properly, cell walls in the cassava tuber are broken down by Lactobacillus bacteria, permitting endogenous enzymes normally sequestered from the cyanogenic glycosides to hydrolyze the toxin. The production of lactic acid during fermentation also acidifies the environment and provides a favorable milieu for other microorganisms to contribute to the hydrolysis of up to 95% of the toxin prior to consumption^85,87.

By doing this outside the body, the new theory goes, our ancient ancestors were able to dispense with a significant portion of their digestive tract and invest the freed energy into brain growth. The rest is history…

A nice diagram explaining the potential evolutionary benefits for our ancestors of the discovery of external fermentation

Whether or not this new theory is true, it’s absolutely true that eating fermented foods is very good for you indeed.

Let’s get fermenting!