Kakawa, Xocoatl, schokolade, chocolat

Yes, even chocolate is a fermented food.

Theobroma cacao trees (chocolate bean) flourish in the humid biospheres of Central and South America, and have now even made their way to Africa and the Hawaiian islands. The word Kakawa (which all other forms of cacao and chocolate derivate) comes to us from the ancient Olmecs, who were probably among the first civilization to taste the so-called food of the gods millennia ago. After Europeans got a taste of the thick, bitter, and aromatic drink made from cacao beans, a worldwide love-affair quickly developed. Chocolate is now consumed in tremendous amounts planetwide and in many different forms. While you should, and probably do eat chocolate on a regular basis, few people actually know the first step to making quality chocolate is fermentation.

By Photo by Medicaster. - en:Image:Cocoa Pods.JPG, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2973927

Chocolate starts its life as a brightly colored pod with a leathery rind that grows directly from the trunk of the cacao tree. Once the pods become dark purple they are considered ripe for picking. Inside you will find a white pulpy material known as mucilage, as well as numerous beans containing the precursor material to what we know as chocolate. The beans are separated and collected and then put into simple wooden boxes along with some of the pulp to begin the fermentation.

The fermentation is usually a spontaneous process (no added microbes) that is helped along by some of the chemical attributes of the cacao bean (lots of good sugars for microbes to munch, plus a healthy dose of citric acid). There are three distinct microbial communities that access the sugars and other molecules from the pulp to ferment the beans. The first group to the table are yeasts from an interesting genus called Hanseniaspora, which consume all available oxygen, while producing some alcohols, and lowering the pH of the fermentation. During the primary fermentation by the yeast (about 48 hours), a secondary group of lactic acid bacteria further consume sugars that have been made accessible by the yeast, producing lactic acid and keeping the pH low. One of our friends Lactiplantibacillus plantarum, (formerly Lactobacillus plantarum), often becomes a dominant bacteria during this phase which can last around 72 hours total. The last to eat are the acetic acid bacteria which typically arise once the fermentation is stirred with a large shovel or hand crank. As aeration increases, an exothermic reaction (that is, one that gives off heat) converts the alcohol into acetic acid, and temperatures can reach a staggering 122 degrees F (50 degrees C). The main bugs found to produce the acetic acid are Acetobacter pasteurianus and this final phase tends to last until the 4th or 5th day.

— Image from Schwan, RF, & Wheals, AE. (2004). The microbiology of cocoa fermentation and its role in chocolate quality. Critical reviews in food science & nutrition, 44(4), 205-21.

The whole process is fairly straightforward, however if the beans are left for too long, over-fermentation leads to a rise in bacteria in the genus Bacillus and filamentous fungi that can cause off-flavors to the final chocolate product. The beans are then sun-dried, roasted to some degree, and ground before further processing into cacao nibs and blending.

Microbes Matter

Interestingly, the fermentation process has a distinct impact on the flavors and aromas of the final chocolate products. Cocoa beans (cacao beans are called cocoa beans after fermentation for some reason), contain all essential cellular components of life including water, fats, proteins, fibers, and many interesting molecules called polyphenols. One way to understand how microbes change the final product is to do test fermentations with one group of beans inoculated with specific microbes and another left to ferment spontaneously. This work was done by Brazilian researchers and published in the journal Molecules in 2017. Through the use of a chemical analytical instrument (Gas Chromatography - Mass Spectrometry) as well as human sensory surveys, the authors found that chocolate produced from fermentation with just three added microbes: Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 was found to be less bitter, and have more of a pronounced cocoa flavor than beans that were spontaneously fermented. The authors attributed this to production of the alcohol 2,3-butanediol, which gives flavor to cocoa butter (sweet chocolate), and 2,3-dimethylpyrazine, which gives caramel and cocoa flavors. These two compounds were only present in the inoculated chocolate samples.

Omnia in Mensura (all in moderation)

The health benefits of chocolate are well-known and should be celebrated! Of course when I say eat more chocolate, I mean dark chocolate with limited amounts of sugars and fat added (milk chocolate being fairly unhealthy). The main health promoting molecules found in processed chocolate are polyphenols.

Polyphenols are a very diverse group of molecules which are overwhelmingly associated with benefits to human health including antioxidant and anti-inflammatory properties, regulation in fat synthesis and degradation, as well as glucose homeostasis. These metabolic improvements reduce the risk of obesity-induced disorders due to an increase in the expression of something called the peroxisome proliferator-activated receptor (especially PPAR-gamma). Cocoa polyphenols have also been shown to cross into your brain and improve the growth of synaptic connections and neuronal viability (brain cells are more connected and are more active). For a full review of health effects of chocolate see this article from Sorrenti and colleagues published in the journal Nutrients from 2020. There is also a positive influence from chocolate polyphenols on the intestinal microbiota, with beneficial members of the lactic acid bacteria increasing in your gut from chocolate consumption. All-in-all chocolate is a fermented food you should add to your diet and not feel guilty about, provided you choose the right stuff.

Please chonk responsibly

With globalization and the click-to-buy culture we currently rely on, it can be especially challenging to find chocolate that is both good for you and good for the planet. To get up on my soapbox for a moment, there is an urgent need to seek out chocolate companies which are transparent in their supply chain. Those companies are more likely to actively decrease native deforestation efforts and are also more likely to avoid child slave labor. Unfortunately, it is not always clear where beans come from, however, cocoa beans originating from West Africa should be avoided as it was estimated in 2013-2014 there was upwards of 1 million children involved in hazardous working conditions (child trafficking and forced labor) originating from Ghana and Cote d’Ivoire. One company I did find that seems to be on the up and up is based out of the Eastern African island of Madagascar: https://www.beyondgood.com/. This company claims to work directly with farmers to promote education and providing higher wages, and also to keep native forests of Madagascar thriving. By even just taking 10 minutes to google where your food is coming from and what companies are involved, you can make a huge impact on the earth.

Disclaimer: The opinions expressed in my articles are my own and do not reflect those held by the authors or publishers of the articles discussed herein. I do not claim ownership of any of the data, or images presented.

Thanks, I hope you enjoyed reading. and see you next time.