Follow Along Fermentation
My first fermentation of the year is large for me but still tiny in the world of fermenting cacao beans. Follow along as I journal each day.
Hau'ole Makahiki Hou!
My cacao adventures this year started with a fermentation. I thought I would document each day in photos and observations, so you can follow along. I try to be as detailed as possible for people who also ferment at home, yet I hope it will be of interest to cacao enthusiasts who may enjoy more insight into the transformative process of fresh cacao seeds to delicious cocoa beans. The post below is structured but a bit messy, just like a cacao fermentation :)
Please note that I don’t ferment like the professionals, think cake factory versus a cake baked at home. I’ve been fermenting at home-scale for over a decade and consistently enjoying great results: delicious chocolatey chocolate lacking too much bitterness, astringency, or off-flavors.
I don’t intend this post to be a protocol to follow, it is just an example. There are many ways to achieve delicious cocoa beans, and no right way. Being willing to experiment and adjust according to what the fermentation is telling you is important for consistent success. Each fermentation I embark on is different adventure; let’s see where this one leads together.
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2 January 2024
My friend Guido and I picked 170 pods of mixed cloned trees in Hilo. We hadn’t harvested pods for at least a month, so they may have tended toward the riper side. I had no idea how many there were until I counted at home - and then panicked a bit. I was hoping for a mostly hands-off, incubated ferment, but this was too many pods.
As an aside, my current favorite ferment size is about 20-30 or 40-60 pods (depending on size), enough to fit nicely in either one or two 1-gallon glass jars. Using a temperature controlled incubator means not much babysitting is involved. However, my most flavorful batches I’ve worked with have been larger, pour-them-in-the-cooler style, 200ish pods, so this abundance of pods is a blessing. (Working with cacao at all is a blessing!)
4 January 2024 - Day 1
I picked 14 pods from seeding trees at home to add to the pod pile and cracked pods with Jeremy. It took about an hour, finishing around noon. We ended up not using eleven pods because their seeds were tiny and dry or because they had sprouted. Overall, the fruit pulp was nicely ripe. The seed sizes were mixed with many quite large and many quite small. While this is not ideal for homogeneous fermentation, drying, or roasting, it may allow more complexity the chocolate flavor. We’ll see!
In the past, if not using glass jars, I would put the freshly-liberated seeds directly in the fermentation cooler (an old picnic cooler). This time I employed a 6-gallon fermentation bucket for the first few days (yeast-phase) of fermentation. The spigot at the bottom allows for easy draining of the juice, which is a huge advantage over our cooler without one.
I lined the fermentation bucket with rinsed banana leaves and weighed the seeds in batches as I put them in. The final tally was 18.897 kg for 173 pods. They filled about 5 gallons of the 6-gallon bucket. I embedded a cheap probe thermometer in the middle of the heap, loosely placed on the lid, and used what was at hand (a cushion and towels) to insulate the bucket. I wheeled the bucket into the warmth of the sun during the day and brought it to our carport to tuck it in for the night.
About that thermometer: the probe will read one point in the middle of the ferment. This is a terrible indicator for how the whole ferment is going. Cacao beans are great insulators, and it is very common to find large differences in temperature between different parts of the ferment. Having the tiny window into temperature that the thermometer provides is just one data point to judge how the fermentation is going.
5 January 2024 - Day 2
No disturbing the seeds on day 2. The wild yeasts should be starting to grow, transforming the sugars into alcohol. Unfortunately these winter Days are cold. I’d like the ferment to be at about 95°F during this stage, but the highest temperature I saw was 80°F. At 3:00 pm, we drained the juice, collecting 770 g. The juice was delicious, still tasting fresh. It went in the refrigerator for a couple of weeks to turn sparkly.
6 January 2024 - Day 3
At around 11:00 am, we drained about 400 grams more of juice, again whisked away to the refrigerator for later enjoyment. This time the juice tasted slightly alcoholic. The temperature of the seeds read 82°F.
At around 4:30 pm, I opened the lid to find some white dots in the top. I wish I would have taken a photo. This is completely normal and expected, most likely from the yeast. I mixed the seeds by grabbing handfuls and transferring to a 5-gallon bucket, paying attention to rearranging the seeds. A bit of attention and effort is required to get a thorough (as thorough as reasonably possible) mixing with this volume.
My big concern in any fermentation is mold. At this volume of seeds, the heat generated by the ferment may not be enough to dissuade mold growth in the cold corners of the container. This has happened to me before, and I would prefer to avoid it. I’ve found that adding in some heat via jars with hot water helps, I will do that for this fermentation, too.
In the past changing the bottles has been a nuisance. Mischievous seeds can tumble into the bottle cavity and get trapped, drying out under the bottle. Pushing them back is difficult, especially if they are slippery with fermented fruit gunk. Just thinking about dealing with that gives me a sense of dread. Well, perhaps just a mild sense of dread but finding a solution would be a relief. This is all preamble to why I am so smitten with this tiny and simple hack I’m trying for the first time. I taped a flexible plastic cutting board to make a sleeve that a half gallon mason jar slides into*. Unfortunately I had only one of these cutting boards on hand, so I taped together a second sleeve using flimsier plastic film sold for wrapping around fancy cakes. The two sleeves go in two opposite corners of the cooler, then the banana leaves line the surface between them and the fermentation in the middle.
Then came the question of what temperature water to use in the bottles. For this size fermentation, I expect some heat to be generated by acetic acid bacteria but maybe not enough to properly kill the seeds, which is essential to develop the deep chocolate flavors. When setting up tiny fermentations in glass jars, I often will fill the water jars with 170-180°F water. The jars of hot water warm the air which warms the jars of seeds. The thermodynamics of this fermentation is different because the seeds are right up against the source of heat (with a glass, plastic, and banana leaf layers in between of course). I don’t want the heat to be so high that it damages the beans, and I don’t know what temperature is too high. On the other hand, the volume of the jars is much less than the volume of the fermentation, so if the heat were to flow out evenly, the water would need to be much hotter than the target temperature. Cacao beans are a good insulator, and I expect that heat from the hot water jars is released throughout the fermentation slowly. Therefore the hottest part of the fermentation will be at the areas where the beans are near the hot water jars, and the in situ thermometer is measuring in one of the cooler areas.
I honestly had no idea what the “best” temperature would be or how to figure that out. Based on intuition, I started the water bottles at 130°F, which I considered to be a lowish temperature that could support yeast growth, since the sweetness in the taste of the ferment told me that they were not yet done. Yeasts generally like around 90-95°F and the ferment was less than 80°F after turning.
After placing in the heated water bottles, I put a piece of banana leaf on top and placed the lid on the cooler. I bundled it in blankets and left it to do its thing, crossing my fingers.
At 6:30 pm, I warmed the water, which had dropped to 110°F to 150°F, reasoning that the extra heat would help keep it warm overnight. I tucked the ferment in for the night.
* Later edit: The cutting board sleeve worked so well, making caring for this fermentation so much easier than similar ones in the past. I will definitely use again!
7 January 2024 - Day 4
Now that I’ve explained the general process of reheating water jars and turning/mixing the ferment, I’ll write the details of each day in shorthand.
Time Thermometer temp Water temp Water heated to Notes
5:30 am 92 ? 150
12:45 pm 95 ? 150 1385 g juice drained
3:30 pm 98 ? 150 turned, juice drained
6:30 pm 98 ? 150
The fermenting fruit pulp was flocculant and starting to come off. The juice tasted a bit alcoholic, sweet and sour.
8 January 2024 - Day 5
Time Thermometer temp Water temp Water heated to Notes
4:30 am 108 ? 150
3:30 pm 102 ? 150 drained, turned, new leaves
6:30 pm 110 130 170 drained juice
The pulp is now light pink and developing a few purple and brown spots, good signs. The pulp taste is tart and alcoholic, and the fermentation seemed like it was starting to make its own heat. Is it moving on to the next phase? I stepped up the heat in the water jars to help it out. Still just guessing here.
9 January 2024 - Day 6
Time Thermometer temp Water temp Water heated to Notes
5:00 am 110 110 160
11:00 am 110 115 160
3:30 pm 110 120 160 turned, 100° after
6:00 pm 102 130 160
The pulp is clumpy a falling off the beans, which is great! The pulp is noticeably darker, and the seeds near the bottom feel a bit slippery. There are some slime strings, which makes me concerned about what I call “slime out,” a situation which makes delicious chocolate but is quite messy. The cut seeds have brown acidic liquid inside “gravy,” and the groves in the cotyledons are still tight.
10 January 2024 - Day 7
Time Thermometer temp Water temp Water heated to Notes
4:30 am 110 107 160
11:00 am 110 115 160
3:30 pm 110 115 160 turned, 98° after
6:00 pm 110 ? 160
The pulp is a bit darker. The slime-out situation has not progressed. The inside of the seeds show gravy and some grooves. Aroma is hard to describe, but what I expect.
11 January 2024 - Day 8
Time Thermometer temp Water temp Water heated to Notes
5:00 am 112 105 160
12:00 pm 102 110 160
3:00 pm 104 130 160 turned
6:00 pm 104 125 160
The pulp is a bit darker, and drier. Less pulp clumps onto my hands, but the seeds are looking more stripped of fruit and inflated. The pulp around the upper beans feels tacky while the bottom beans feel slippery. The flats (fruits with no seed inside) are starting to differentiate themselves by sticking to my hands. I take them out as I discover them, which saves work later. The taste of the beans is more chocolatey and less raw. Getting close!
12 January 2024 - Day 9
Time Thermometer temp Water temp Water heated to Notes
4:30 am 110 108 160
10:30 am 112 115 160
3:30 pm 112 120 160 turned
6:30 pm 100 130 160
The pulp is a darker, drier, and has a bit more slime. The seeds near the heated water jars are much drier. The scent of the pulp has a chocolate note, which a sign it is time to end. Weirdly, the three beans I opened seemed less advanced than the ones on previous days: less gravy and tighter grooves. Not sure why. They tasted good, though, so I’m not too concerned.
13 January 2024 - Day 10
Time Thermometer temp Water temp Water heated to Notes
4:30 am 108 105 160
8:00 am ? n/a n/a turned, started drying 1/2
9:15 am n/a n/a 160 continued with 1/2
3:00 pm 100 115 160
7:00 pm 105 125 160
I’m pretty sure this ferment is ready to be dried. I often like to take time points to compare for these larger ferments. This gives insight into how the flavor is affected by fermentation time and maturity. Plus, it is easier to handle the first day of drying with fewer beans at once.
I have four nice drying trays (thank you, Jeremy!), and I decided to fill two of them. The weight of the ferment at this point is 14,186. Divide by four to get 3,546 on each tray. That leaves 7,094 g in the fermentation box.
I’ll continue to follow the ferment drying in a follow-up post and just focus on the beans still in the fermentation box here.
14 January 2024 - Day 11
Time Thermometer temp Water temp Water heated to Notes
4:30 am 100 107 160
8:00 am 104 n/a n/a started drying remaining 1/2
I started drying the rest of the seeds to dry. The vinegar smell is much stronger than I’m used to and the beans have a chocolatey flavor. Will I prefer these beans or the one taken yesterday? Can’t wait to find out!
Overall fermentation reflections:
This ferment seems to have gone well, with no mold take-over or weirdnesses. (I am relieved, for sure, but I have still posted this if problems had occurred.) The fruit broke down and fell off the seeds, darkening as expected without slime-out. The fermentation products were entering the inside of the beans, which did change flavor over the course of the fermentation. The plastic sleeve innovation made changing the water jars easy, and, after the first few days, I didn’t notice any overly cool pockets when turning the beans.
Was 160°F a good temperature for the water bottles during the bulk of the fermentation time and did I reward them at good intervals? I’m not sure. I’d consider lowering the temperature next time. Next time I will probably take measurements of the temperature of the beans close to the heat sources for more insight.
Stay tuned for posts on the drying phase later this month, and the chocolate tasting next month!
Of course I filled out a fermentation record form to keep track of the ferment. Want to use my form? Find it here.
Please give me feedback:
What do you think of this kind of content? Would you like to see more detailed fermentation posts like this one? Did I neglect to include details you’d like to see?
This is so interesting, thank you for sharing the process!
Fascinating. The average consumer needs to learn more about the fermentation phase....