Cacao Fermentation with Olivier Fernandez of Gaston Chocolat

Olivier Fernandez of Gaston Chocolat

Cacao fermentation? What is it all about? How does it affect cacao flavor? Why is it so important?

Olivier Fernandez of Gaston Chocolat makes tree-to-bar craft chocolate in Vanuatu from cacao beans that are grown there. This interview is specific to cacao fermentation and Olivier’s experience/knowledge with fermentation in regards to Vanuatu cacao and location. Quite informative!

Victoria Cooksey: Will you give a brief description of the cacao fermentation process?

Olivier Fernandez: The fermentation is the second step in the process right after harvesting. It is said to require a minimum of 80kg of green beans to work and could possibly be done on a smaller scale with heating assistance but our experience in the field led us to use a standard 200kg size box. Below, we believe the critical mass to get to the right temperatures is not achieved. It is common to see farmers ferment into bags or digging holes in the ground covered in banana leaves, however we never experienced favourable tasting results from such practices and always witnessed inconsistency from one batch to the next. The fermentation is a two-step transformation of sugars and fats, with a first step consisting of a transformation of the sweet flesh wrapping every bean into a juice which has to drip through the box and out to create space in-between beans and activate the second phase with air and bacteria coming into play. Beans are braised a few times in the second phase to re-introduce fresh air and revive fermentation. Both the length of the fermentation and number of braising vary based on the genetics, the outside temperatures and the flavours you want to develop.

VC: Why is the fermentation process of cacao important?

OF: To us, fermentation is the most critical step in the whole process, the moment you develop the precursor of the chocolate aromas and magnify the cacao you are working with. Let’s put it that way, you could have the finest genetics to work with, if you miss on fermentation your chocolate will taste terrible. Now you could work with mainstream cacao and master fermentation and end up with beautiful and unique chocolate. We believe it speaks volume on how critical fermentation is, and this is common to both cacao and coffee, with a trend for more and more experimenting on flavours and complexity of both when altering variables in the fermentation process. 

VC: What are some “off” flavors you have noticed if cacao is under fermented? If it is over fermented?

OF: An under-fermented cacao will have a high level of ammonia and literally smell pee, it’s simply terrible and beans will have a typical purple colour when you do your cut test. For the over-fermented, it is more the mouldy flavours, cheese flavours that you will detect. Now you should realize that unless you practice grading upstream in the process, you will have a disparity of size in the beans entering into the box, and it implies that smaller beans will ferment faster than larger ones, thus you will always have a disparity in cut test and what you are looking for is the mass result. In previous interviews we pointed out how the pre and post-harvest handling of beans could make a difference and this is mostly related to what will enter the fermentation box. 

VC: Does the type of material/wood the cacao is fermented in affect the final flavor?

OF: Yes and no. We believe that essences of woods which are prone to release sap in the process should be avoided and so are any type of treated wood like timber used in building or logistic for palettes which are loaded in chemicals for long resistance. At Gaston we used reclaimed wood from trees that were damaged during cyclones. Now telling you that a particular type of wood would give a specific flavour, we believe it would be exaggerated. Not that there is no interaction between the wood and the beans, though we use banana leaves to isolate the beans from the box, but because the magnitude of other variables on the final flavour like the duration or the type of bacteria interacting with the beans in the process is way more important. It is also to be said that we do not work in labs thus each batch has slight variations from the previous one since we have no grip on weather and outside temperatures.

VC: Is the cacao used in your chocolate bars farmed, or is some/all of it wild cacao that is collected?

OF: The Cacao grows in plantations in Vanuatu, you would get wild trees in random places from birds and animals moving seeds but cacao was all man planted in the beginning and plantations are mostly dual crops with a shed from coconut trees. That said, some abandoned plantations would now look a lot closer to wild than a proper plantation and these are still harvested. A main work we are conducting is to restore some old plantations and get them back into operations with a source of income for the farmers. Know that in Vanuatu the amount of man planted areas is small compared to the vast size of tropical lush rainforest. Logging is limited and there is no mining. We do not face issues of deforestation and people have a profound sense of balance and respect for nature. 60% of agriculture in Vanuatu is for subsistence, not commercial.

VC: Did you begin to make chocolate before you worked on fermentation with growers/cacao collectors, or after?

OF: Like most chocolate makers yes. I was blending beans with sugar and other ingredients and enjoyed what came out no matter what or how terrible it was. Always had fun in the process. However, I would say it is only after we went back into the field and spent a few years on fermentation and plantations rehab that we really started to make chocolate. We chose on purpose to settle Gaston in Vanuatu for it is a country that grows cacao and an origin which has yet to make a name for. Work with the trees is the key and we would not conceive to run Gaston in another way. I worked from bags of beans without contact with the farmers in the past and you are bound to make something with the beans no matter what comes out of the bag, and believe me it is not always great. Though I took it as a challenge back in the days, there was a lot of frustration into the process too.

VC: What has been the biggest challenges in educating growers/cacao collectors on how to ferment cacao? (Or did they teach you about fermentation?)

OF: Vanuatu had a commodity type of cacao market before we began our work and fermentation was the least of the concerns with little attention paid to it and a focus on volumes. Prices dropping through the years didn’t trigger any will to invest or maintain plantations, the local market being controlled by a handful of intermediaries shipping overseas for a nice mark-up. It was only after we ran a few workshops on how to ferment cacao and access fine flavour cacao niche market that farmers realized there was an alternative that would drive higher incomes but requiring more work. It didn’t click in every location we tried to develop our program and we were confronted to lack of will and doubts regarding the changes we were introducing in a process that had been ran for decades in a mechanical repetition of harvest, dump beans in boxes until it’s full (even if it meant to fill the box over three or four days of work), turn the beans three times over 7 days and dry them on hot air type of dryers. Indeed, the process is quick and completed in 10 days when our technique requires at least 18 days between harvest, fermentation and drying. We also faced the terrible outcomes of programs destined to help the farmers and led them to believe that sun drying was the key and only requirement to qualify for fine flavour cacao. Organisations would mislead the farmers on prices, pay them a premium over commodity market price that did not capture the additional time and work it take for sun-drying and leading to another drop in efficiency and revenues for the farmers. These were our main challenges and it took three years and a few success stories to materialize to convince more farmers of the good of this work. To restore a scale of pricing, we studied every part of the process, timed and priced it and came up with a transparent system. We pay two to three times above the commodity cacao market and our price is net into the worker’s pocket which means we pay for transport, bags and insurances required to move the beans to our processing facility. 

VC: What has been the most rewarding part of helping others improve the fermentation process?

OF: The farmers are connected to their cacao in a way we didn’t witness before. They now see it as a valuable crop and source of income. We have seen a constantly growing number of farmers wanting to join our program and started with 3 to reach about 120 last harvest. You might find it small and it is the measurable extent of what we can do at our scale. Let’s be honest, we did the work to enhance the quality which serves us as well and we are not here to save the world. Our packaging doesn’t talk about fair trade or socially responsible behaviours, we simply do it. We believe that for as long as we use it as a marketing tool it will not become the norm. Everyone in the bean to bar movement is aware and has good practice. I personally believe it is a signature of this branch of the chocolate industry. At the end of the day what matters is that farmers have a better management of their resources, plant new trees for the future generations and work together to achieve quality that pays. Customers are no fools and they don’t need labels to make the difference.

VC: What has been the most surprising thing you have learned about cacao fermentation?

OF: The way flavours develop based on timing and braising is the key, acknowledging that you have made the necessary work to build functional fermentation boxes in a good environment. You can literally have two to three flavour profiles depending on genetics based on alteration of these two variables.

VC: How does weather affect the fermentation process?

OF: The variations of temperatures between winter and summer harvests are affecting the fermentation, at night the fermentation would slow down in winter forcing us to develop different fermentation profiles to get more even results across batches. The number of braising and days of fermentation has such an influence over the final result that we firmly believe it is the main trigger for variations of flavours from one farm to the next in a same region. The bacteria in the air are pretty consistent across the same region and so are the soils and water precipitations. It is virtually impossible to recreate the same fermenting conditions batch after batch unless it is done in a controlled environment like a lab. This is why we focussed on the process more and developed simple practice that would get consistency. Still we see variations over the seasons and batches.

VC: Have you experimented adding in other inclusions during the fermentation process to add to the final flavor? If so, what are your thoughts on that process? What are your thoughts on double fermentation? Any flavor changes with that style?

OF: On a small scale we experimented inclusion of passion fruit in the process which proves unsuccessful after roasting. Though we had flavoured beans after drying with residual parts of passion fruits, these same flavourful vegetal parts burned in the roasting process which was fairly disappointing and didn’t have the effect we were expecting. There was a remaining of acidity but you would not have been able to distinct from which fruit is was. Now, there are so many variables that we can play with already that inclusions are more of a trial for fun at this point in time. On a similar experience, one of our bags travelled on a ship next to a hand of ripe bananas and loaded in flavours which you could detect later in the process. At the time we are more focused on ageing of nibs to see what can be achieved. If you don’t see it in our range of chocolate, it means our attempt failed or was not convincing enough. 

VC: Is there anything you would like to see change about cacao fermentation in the future?

OF: We would love to see chocolate makers more involved in the fermentation process itself. There is a hype about travelling the world to scout new beans paid at farmer’s gate but little is shared about fermentation profiles. I like the work of plantations like Ingemann who are offering two to three fermentation profiles per genetics, this is future, this is how we’ll keep on bringing new flavours and this is worth for cocoa butter too and the market of milk and white chocolates.

Thank you so much for this interview on cacao fermentation Olivier!

*All photos in this interview were provided by Gaston Chocolat.

For more on Olivier Fernandez check out my interview with him on this blog from last year: https://darkmatterschocolatereviews.com/2019/08/03/interview-with-olivier-fernandez-of-gaston-chocolat/

For additional information on cacao fermentation check out my interview with Luisa Abram on the topic: https://darkmatterschocolatereviews.com/2020/01/18/cacao-fermentation-with-luisa-abram/

Olivier Fernandez/Gaston Chocolat:

https://www.instagram.com/gastonchocolat/

Victoria Cooksey:

https://www.instagram.com/victoria.cooksey/

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