Funky Fermentations: The Chocolate Edition
A cacao pod sliced open to reveal its seeds (or beans)
Hello, friends! It’s been a minute. I write to you from Southeast Portland, where it is currently 1° above freezing. That is a sharp contrast to temperatures at the location I’m about to describe, the gloriously warm tropics of Hawaii. The Big Island is one of my happy places, the best spot I know to relax and revive, and I spent a couple weeks there this past, non-working month.
In my time there, I discovered a process with surprising relevance to this blog and the world of brewing. As a way of transitioning from the turquoise bathwater-warm seas of the Aloha State to the freezing drizzle of (equally but differently beautiful) Oregon, let’s dig into this fascinating world.
The eastern slopes of Hawai’i (the formal name of the Big Island) are bathed in over a hundred inches of rain a year, along with consistent high temps that are never that high, and lows in the sixties—even in January. That makes it a perfect place to grow tropical delights. Tom Menezes has been growing various organic fruits just north of Hilo since the turn of the century. In 2006, he planted cacao trees, and in 2008 began turning the pods he harvested into chocolate in his tiny operation, Hawaiian Crown Chocolate. Years ago, Sally and I had a blast at a coffee farm on the other side of the island in Kona, so we thought it would be fun to tour the farm.
I was just there on vacation, not planning to spring into work mode, but my spidey senses started tingling when our guide, Jonovi, flipped up a banana leaf to reveal a whitish film underneath. She raked her fingers across it to illustrate that it was a substance, not the leaf’s coloration—and of course identified it as yeast. This is an important component of processing cacao, which turns out to involves fermentation. Fortunately, no one else had signed up for the tour, so we did start paying close attention to what came next, and I asked a million questions (sorry Jonovi!).
The cacao tree is unimpressive—short and spindly—but it becomes laden with disproportionately-large seedpods, which start out dark and turn yellow. Jonovi pulled out a knife and sliced a pod in half, revealing a cone of tightly-packed seeds. She broke them apart and gave us one to eat. I was surprised at how sweet and fruity they were—similar to rambutan, longan, or lychee, all similar white-fleshed tropical fruits. (The sweet portion actually tasted at least as good as those other fruits, though as I worked one in my mouth I could see there was no way to easily separate them from the seed, for which humans discovered had even greater purpose.)
The seed was soft and bitter, though complexly so. In the picture below, you can see what it looks like—not a single piece, like an almond or cashew, but a brain-like collection of lobes and whorls.
The underside of a banana leaf.
A spindly cacao tree and pod.
A bean split in half.
Fermentation
For our purposes, the magic happens next. The sweet, sticky fruit on the outside of the bean is critical to transforming the inside into grist for chocolate—and it happens just like spontaneously fermenting a beer or wine/cider. Tom puts the beans in a cooler to preserve the heat fermentation will generate, and covers them with those yeast-covered banana leaves. Over a period of days, yeast and bacteria will attack the fruit pulp, conducting separate alcohol and lactic fermentations as well as other microbiological transformations. Tom described them as separate processes one can smell and observe as the days pass—just as happens in lambic. He had coolers with beans in two different stages of fermentation (see below), and they wafted amazing and familiar scents.
While I can’t speak to the specific microbes present in Hawaii, they’re probably quite similar to those described in Venezuelan cacao fermentation:
The fermentation process of cocoa is characterized by a microbial succession in which the yeasts participate first, then the lactic acid bacteria (LAB) act and, finally, the acetic bacteria (AAB) intervene. Additionally, spore-forming bacilli of the genus Bacillus, and filamentous fungi. This process is essential both to modify the beans, eliminating the mucilage, and to prepare the grain that requires a battery of enzymes responsible for modifying its color, taste and smell.
Two dominant bacterial species Lactobacillus fermentum and Acetobacter pasteurianus, together with four yeast species Saccharomyces cerevisiae, Hanseniospora thailandica, H. opuntiae and Pichia kudriavzevii, represent the central component of the bacterium-fungus association that lead to the fermentation of cocoa in many of the regions where it is produced.
Once conversion is complete, Tom spreads the beans on mats to dry. The fermentation penetrates the skin of the seeds and transforms the starches inside (in this way it’s something like fermentation and malting all at once), and now the lobes are fractured and rattle when you shake them. Those particles are the “nibs,” and Tom will roast them in a drum roaster back at his shop, grind them, and turn them into chocolate.
Early in the fermentation process.
Further on.
Dried beans.
All of that is fascinating enough, but wait, there’s more! Having seen and particularly smelled the process from the start, I was startled to discover that a big part of the flavor profile of chocolate came from the fermentation. It contributes a complexity and fruitiness that is especially evident in the dry, roasted beans Tom sells at his shop in Hilo. The type of fermentation affects how the chocolate tastes, and this was also a big revelation. I’ll admit it up front: I am a chocolate plebe. I don’t love the ultra-high level cacao dark chocolate bars artisanal chocolatiers seem to prize. To my palate they taste too bitter, and they’re waxy, like sucking on a Crayola.
That is apparently not a given (and wasn’t the case with Tom’s chocolate, which while bitter, were also fruity, nutty, and rounded). Fermentation affects the flavor and bitterness of the chocolate. It’s a complex process I won’t pretend I fully grasp after glancing at a couple scientific papers, but breaking down polyphenols and three other compounds (epicatechin, catechin and procyanidins) seems to be a big part of reducing the bitter flavor—all of which comes from fermentation. So what you find under those banana leaves and floating in the atmosphere may be as important as the seeds farmers harvest. People who make beer for a living are probably nodding wisely.
By the time the final chocolate was processed, the fermentation character had fallen to the background. Because chocolate is such an intense flavor to begin with, I’ve never noticed the fermentation flavors. In bars of Hawaiian Crown, I was able to locate them from the dried beans and scents of fermentation before them.
The drum roaster.
The dried and roasted seed cracked open (nibs inside).
Tom Menezes with tour guide Jonovi at the Hilo shop
The moral of the story is that most of the tastiest things in life are fermented: beer, cheese, coffee, and chocolate. For the most part we look at the ingredients of these foods and beverages, and are blind to the efforts of the tiny yeasts and bacteria busy transforming them. But in each case, those little creatures are key to the very reason we think these products are tasty in the first place. I recommend you track down a chocolate bar, an appropriate beer, and do a little field testing yourself.