What is Thermoshock Processing?
In this post we will be discussing the technique, what makes it special, it’s origin, it’s founding farmer, and how processing coffee in this experimental way has influenced the specialty coffee industry. Let’s start by acknowledging that not everyone high up in “bean land” agree that thermoshock is a fermentation process. Now more than ever, producers of specialty coffee are coming up with increasingly progressive ways to highlight the natural flavours that end up in your cup! It is also worth mentioning that the coffee taste notes we highlight in specialty coffee are not added to the coffee. Yes, there are some processing methods that introduce natural fruits into the fermentation but nothing you taste, at least nothing we roast here at Karvan, is an artificial flavour. As specialty roasters we are in the business of roasting high scoring coffee (80 and above points out of 100) and our roasting team procure green beans that have specific characteristics that are brought to your cup during the art of roasting.
Thermoshock is a type of anaerobic fermentation process that greatly enhances a coffee’s level of sweetness. It is not an easy process, nor quick. It is a tricky method to get right and requires a combination of high quality coffee and a high level of skill. A farmer not only risks his financial security but also his reputation.
Wilton Benitez "a founding a farmer"
Wilton Benitez is a highly specialised Colombian coffee producer, with over 12 years of experience in cultivating some of the world’s rarest coffee varietals. Wilton currently owns and operates 3 naturally diverse coffee farms located in Piendamo – Cauca in Southwestern Colombia, at a height of 1800 – 2100 masl. There’s La Macarena (75 hectares), Las Brisas (22 hectares) and Granja Paraiso 92, the smallest of the three at just 5 hectares. Granja Paraiso 92 is where our three coffees were grown.
Where science meets passion
Everything is about control. The process is complex, but if the conditions are controlled and managed, the results create distinctive flavours.
Wilton comes from a family background in coffee production and started his coffee journey on the family farm. Here he discovered the true potential of coffee through fermentation technology. Wilton took a keen interest in how fermentation practices were delivered in other industries such as wine, beer, and cheese – to aid the development of new and unique flavour compounds. As his understanding increased, he started developing his own protocols for coffee processing.
Coffee & Innovation
Wilton currently owns and operates 3 naturally diverse coffee farms located in Piendamo – Cauca in Southwestern Colombia, at a height of 1800 – 2100 masl. There’s La Macarena (75 hectares), Las Brisas (22 hectares) and Granja Paraiso 92, the smallest of the three at just 5 hectares. Granja Paraiso 92 is where our three coffees were grown.
Granja El Paraiso 92
Granja El Paraíso-92 is a family farm that produces different varieties such as Java, Bourbon Pink, Geisha, Pacamara, Caturra, Tabi, Castillo, Supremo and Colombia using highly innovative cultivation systems such as terraces, drip irrigation, shady and nutrition calculations in laboratory all aimed at producing a unique coffee that can be verified through the multiple awards obtained. Finca Paraiso-92 also has its own microbiology laboratory, quality laboratory and processing plant.The processes applied to the different coffees start from a strict selection, sterilization and characterization of the cherry to later start with the first phase of controlled anaerobic fermentation, adding a specific microorganism for each process, then the coffee is pulped and subjected to a second fermentation phase, when the second phase ends, a bean sealing process is carried out through impacts of hot and cold water to improve the organoleptic conditions of the coffee.
Good vs Bad Coffee Fermentation
“With good fermentation, you can draw out the characteristics that a coffee has. In other words, good fermentation will not elevate a coffee’s quality, because coffee already has its quality from the field. But we can draw out and maintain those characteristics that come from the field.”
Yet fermentation isn’t always good. “A bad fermentation, this lowers or produces bad qualities in the coffee,” he stresses.
“In an over-fermented coffee, what we find are wine flavours, but those of wine that has gone bad,” he says. An experienced farmer such as Wilton, even before he cups the coffee, recognises the signs of over-fermentation: the beans have a reddish colour and the unappetising aroma of rotting fruit. For these reasons, it’s imperative that producers understand fermentation.
What influence does Thermoshock fermentation have on the flavour
Benitez’s first trials of the thermoshock method were really all about playing with temperature in particular. During his first trials, Benitez fermented whole cherries without oxygen (anaerobic fermentation) often twice over before washing the pulped beans in warm water, and then cold water directly afterwards. This is where the process gets its name from!
By washing the beans in warm then cold water (playing with thermal temperature), Benitez is shocking the beans into sealing in acquired flavours developed during the double anaerobic fermentation process. Benitez has refined the method.
What is innovative about the coffee that Wilton Benitez is producing?
All Wilton’s coffees undergo a high level of skill and management. The investment in the farm’s dry mill 4 years ago allows Wilton and his team to have control over the full process. This is an important aspect, as although the milling of the seeds will not aid in flavour enhancement, it can impart undesirable taints if the process isn’t clean and well managed.
The dry mill also allows Wilton to pass on some of the processing skills to neighbouring farms. He has adopted a social framework for farmers to share agricultural, processing and milling practices. Wilton reiterates that for farmers to understand their coffee, they first need to be able to taste – to understand which elements need to be addressed for quality improvements.
A step by step scientific breakdown of Thermoshock processing
All varietals have their own life roadmap but we will be exploring that of the Caturra below:
- Manual harvest.
- Characterisation of the cherry.
- Classification of the cherry by density and size.
- Sterilisation of the cherry (with UV and Ozone).
- Cherry fermentation for 48 hours.
- During cherry fermentation, the addition of specific yeast (Saccharomyces pastorianus) to enhance fruity notes. In the beer industry, this yeast strain is favoured when making crisp-tasting lagers.
- Cherry pulping.
- Fermentation for 68 hours in parchment.
- During cherry fermentation natural juices are produced. These are incorporated in the second fermentation, following the pulping process.
- Washing of the seed.
- Drying of the seed with controlled equipment for 48 hours at 38°
Yeast plays an important role in the fermentation process by breaking down the glucose molecules through glycolysis, releasing energy that phosphorylates ADP molecules and ATP molecules. All of this sounds very “science-esk” and it is. In this particular process the oxygen is already restricted. The yeast has to switch to using anaerobic respiration to ensure it can survive. In this survival mission, Ethanol and carbon dioxide are produced.
The influence of bacterial fermentation can be experienced in many goodies we consume, such as sourdough bread, kimchi or beer for example. For centuries food and beverage producers have been practicing the sustainable and environmentally friendly process to enhance flavours but this process is innovative in the world of specialty coffee.
Karvan Coffee Trio x Wilton Benitez x Granja Paraiso 92
We are so lucky to have access to 3 varietals from Wiltons farm, Granja Paraiso 92. To celebrate the great work of this individual producer, we will be showcasing all 3 coffees as a Limited Release Trio roasted for filter brewing.
Sources; granjaparaiso92.com, @wilton.benitez92, bloom coffee project, @far.moore.coffee
