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Online Learning Resources


Here's a list of some great coffee resources we would recommend to further your learning. We aim to keep this list updated as we find new stuff so get in touch if there is something you feel should be included.


Sprudge, your home for global coffee culture and original journalism. Since 2009, Sprudge has been publishing original features highlighting coffee culture, news, and events.

Roasting consultant and author of The Professional Barista's Handbook, Everything but Espresso and The Coffee Roaster's Companion. This blog contains loads of geeky articles about roasting, extraction and beyond.

Coffee blog written by an astro-physicist! A scientific approach to coffee brewing.

World Coffee Research's mission is to grow, protect, and enhance supplies of quality coffee while improving the livelihoods of the families who produce it.

Mainly focused on green coffee, supply chain and roasting. Some fascinating insights from a reputable importer based in Oakland, California.

Loads of industry news and features from the Roast Magazine team.

Upbeat and informative, Perfect Daily Grind is a cross-platform, global network which distributes coffee content to a worldwide audience.

Kasjan Orzol's inquisitive and thoughtful blog aimed at coffee professionals. Interesting writing on products, espresso, roasting and beyond.

Loads of great information and experienced insight on green coffee and roasting.

YouTube channels

The Specialty Coffee Association (SCA) is a membership-based association built on foundations of openness, inclusivity, and the power of shared knowledge. From coffee farmers to baristas and roasters, our membership spans the globe, encompassing every element of the coffee value chain. SCA acts as a unifying force within the specialty coffee industry and works to make coffee better by raising standards worldwide through a collaborative and progressive approach. Dedicated to building an industry that is fair, sustainable, and nurturing for all, SCA draws on years of insights and inspiration from the specialty coffee community.

Re:co celebrates new thinking in coffee – innovative ways to address our challenges, concepts that build our businesses, and fuel to push the coffee industry forward. We invite thought leaders from a variety of disciplines to share their work at Re:co, providing a dynamic force for progress in specialty coffee. We seek to inspire leadership, collaboration, and innovation. Re:co is the place where we share new scientific, agricultural, and economic research, providing essential understanding of the rapidly changing coffee world.

The Coffee Roasters Guild (CRG) is the global trade guild of the Specialty Coffee Association (SCA) dedicated to inspire a diverse coffee roasting community through the development and promotion of the roasting profession.

The Barista Guild is the global trade guild of the Specialty Coffee Association made up of members dedicated to the craft of coffee preparation and service. Through events as Barista Camp and CoLab, as well as our online platform, BG offers easily accessible education to baristas of all levels, driving the opportunity for baristas and the barista profession to develop. It continuously strives to bring our vibrant community together, online and in person, to meet, learn, develop, and grow. Learn more on www.baristaguild.coffee

Specialty coffee household name and author of The World Alas of Coffee provides how-tos, guides, reviews, vlogs, video essays and mini-documentary films. Lovely stuff.

We are sharing stories from the speciality coffee culture in Europe and beyond. We explore the world of third wave coffee by visiting the best cafes we can find and sharing the tips and tricks on how to brew better coffee at home. Follow our channel to make sure you don't miss the next video.

As well as instructional videos for their own brand of roasting machine, there are plenty of educational videos to be found here.


A new podcast series from the Specialty Coffee Association presenting stories, lectures, and debates. The SCA is a non-profit organization that represents thousands of coffee professionals, from producers to baristas all over the world.

Making Coffee with Lucia Solis

Lucia is a former winemaker turned coffee processing consultant. This podcast talks about the steps in getting a coffee cherry ready for roasting, shares current coffee research in microbiology and has interviews with coffee producers in different parts of the world. A fascinating listen!

A platform for learning and debate, Tamper Tantrum have built a library of coffee lectures amassed over the last seven years of live events and interviews as well as hosting a fortnightly podcast.


Having fun talking about coffee while drinking natural wine. Their goal is to discuss current topics in the coffee industry, covering roasting, brewing, coffee quality or business.

How does your choice of coffee affect civil wars, illegal immigration and climate change? Filter Stories is a documentary podcast connecting your morning coffee to millions of hidden people.

FilteredThoughts is a podcast focused on the coffee industry, mainly in the UK. Made up for 7 members talking about recent topics & news.

On-line Resources

The Coffee Exporter's Guide is the world's most extensive, hands-on and neutral source of information on the international coffee trade. It covers trade issues relevant to coffee growers, traders, exporters, transportation companies, certifiers, associations, authorities and others in coffee-producing countries. This third edition marks Guide’s 20th anniversary and includes new material on climate change, the role of women in the coffee sector and comparison of sustainability schemes.

The International Coffee Organisation (ICO) is the main intergovernmental organisation for coffee, bringing together exporting and importing Governments to tackle the challenges facing the world coffee sector through international cooperation. Its Member Governments represent 98% of world coffee production and 67% of world consumption.

A global catalog of varieties covering: Costa Rica, El Salvador, Guatemala, Honduras, Jamaica, Kenya, Malawi, Nicaragua, Panama, Peru, Dominican Republic, Rwanda, Uganda, Zambia, Zimbabwe

The largest collaborative research project on coffee's flavors and aromas ever undertaken. Created at the Sensory Analysis Center at Kansas State University, the lexicon identifies 110 flavor, aroma, and texture attributes present in coffee, and provides references for measuring their intensity. The purpose of the lexicon is to advance our understanding of coffee quality and how it is created, so that we may continue to increase it.

Interactive Coffee Taster's Flavor Wheel, based on Coffee Taster’s Flavor Wheel (2016) and World Coffee Research Sensory Lexicon (first edt. 2016) from SCAA and WCR.

Fascinating report on a long term observational study of water activity in specialty green coffee. Starting in 2012, the Cafe Imports sensory analysis department, led by director Ian Fretheim, set out to start collecting and monitoring water activity in green coffee in the hope that “it would provide a more insightful measurement than moisture content, specifically with regard to predicting the shelf life of coffees. We hoped to answer (or at least partially answer) the question of why some coffees arrive as purchased and some do not.”

Free scientific paper, co-authored by the team at CoffeeMind in Copenhagen. Investigating the relative importance of two roasting parameters — colour (i.e., roast degree) and time — on the sensory properties of coffee.

Loads of free educational resources from this international coffee trader. Covering all aspects of green coffee from varieties and origin info to roasting.

Useful Apps

Our coffee app helps you learn about coffee. Record tasting notes, compare answers with pros, and remember all the things you've tried.

Filtru will let you know when to pour, stir or wait for that perfect bloom. Each step has an indicator of how long it's going to take and what you should be doing - super easy!

VST CoffeeTools is a comprehensive design and measurement application for coffee and espresso professionals, brewing equipment designers, baristas and coffee enthusiasts. Fully functional with or without a coffee refractometer.

A free alternative to VST CofeeTools, unfortunately only available for iPhone. As well as a clean user interface this app provides the ability to record both espresso and filter recipes and measurement data.

Navigate the world of specialty coffee with the Firstbloom app. Expand your list of favourite brews by browsing new coffees and keeping tabs on the latest from the roasters you know and love.

Online Courses

Barista Hustle is here to help the world make better coffee. We are a team of baristas, educators and product designers. We take great pride in being transparent — our website is advertising-free and we disclose all affiliations and potential conflicts of interests. In the modern world of ‘pay-for-content’ marketing, building trust between our community and us in an ad-free online environment is at the heart of what we stand for.

Baristas and coffee professionals from all over the world make use of our free and subscription-based online coffee classes. We have published seven online barista courses. These are visited each week by thousands of freelance baristas, as well as hundreds of coffee businesses looking to offer training and career progression for their ambitious staff.

Coffee Courses were founded in 2012 by Willem Boot an internationally renowned coffee expert with more than 25 years of professional coffee experience, and Valerian Hrala a coffee entrepreneur (Green Plantation Coffee and Unleashed Coffee) and podcast host – coffeeis.me.

Our mission is to help you unlock the secrets of coffee and speed up your coffee knowledge development so you can create the best products for your customers and enjoy coffee to its full potential. With online courses, you can do this wherever you are for a fraction of the price of a live course. We offer courses in the art and science of coffee tasting, roasting, quality management, green coffee production, brewing, barista skills and enjoying coffee.

Ethiopia, the birthplace of coffee. A pilgrimage of sorts for any coffee professional and somewhere we have always wanted to visit. We visited Gedeo and Guji this year with the intention of gaining a deeper understanding of how the supply chain works and gleaning how our purchasing decisions here could have more impact.

Production in Ethiopia is most commonly centred around washing stations (or sites) which typically are set up to process either washed or natural coffees. These can be privately or co-operatively owned and will purchase cherry from small-holder farmers in their local woredas (districts). These “garden” producers usually grow their coffees on the land around their dwellings and make up the bulk of coffee production in Ethiopia. For maximum efficiency, coffees are blended together by quality and are usually only traceable as far as the lot number assigned by the sites who process them and the woredas in which they were grown. To maintain the distinction of these sometimes trademarked regions, at least in Gedeo, we saw checkpoints on the roads to stop the traffic of coffee between them.

You can also find some estates, or plantations, although these are less common. These are inherently more traceable and have the potential to produce higher quality coffees as there can be more standardised agricultural practices in use but are also usually privately owned.

It is also possible to find “wild” forest coffee which account for only 5% of national production, however these trees are usually very low yielding due to the lack of management and are often of a lower quality than their more purposefully cultivated counterparts.

After getting through the craziness of passport control in Ethiopia we were met by Yeshak and his business partner Solomon. Yeshak and his family have a background in exporting and Solomon in coffee and agriculture so these two school friends decided to combine their skills and form a company called Siz Agro Trading who represent several producers in Gedeo.

On the long drive down to Dilla we are struck by the combination of lush green vegetation and dusty earth and notice an abundance of large scale green-houses growing flowers. Yeshak tells us that the main exports of Ethiopia besides coffee are also agricultural; pulses and oil-seeds, flowers, grains, cotton and livestock.

Dilla is on the main, all weather road between Addis Ababa and Nairobi and is the administrative centre of the Gedeo zone. Due to its excellent infrastructure and location it has become the major marketing and transfer point for coffees grown in the south. Both Yeshak and Solomon attended the University here and it’s where Solomon lives.

After my first taste of some traditional Ethiopian food at a local hotel, we headed to Chichu washing station in Yirgacheffe which is owned by Siz Agro. We had a quick tour of the facilities before sitting down to enjoy some coffee, sugar cane and mangoes fresh from the tree. Most of the harvest at this altitude is complete so there was no processing or drying to see but we chatted about their processing methodology and visited the storeroom to see the resting coffee.

Tariku Washing Station

The next morning we headed off to Chelchele via some really dusty roads, to visit a single farm producer, Tariku. The trees were really well looked after and the excellent quality of the picking was evident as we checked out the naturals drying on the raised beds.

In the afternoon we visited three washing stations with Siz Agro; Halo Beriti, Chiriku and Edido. There wasn’t any processing going on but we had a tour of the depulpers, fermentation tanks and saw plenty of parchment being sorted and moved to allow even drying.

Waking up early the next day, we headed out with Falcon Specialty to visit some sites who work with the exporting company SNAP; Banko Dadatu and Koke which are both in the Yirgacheffe Woreda and then Chelbessa in Gedeb, which is owned by SNAP. Following those we paid a quick visit to Aster Aweke a site producing natural processed coffees, owned by exporter METAD. We attracted quite a crowd here and were swamped by the local children all wanting to show us their party tricks.

Wanting to try and fit a visit to another site in before travelling to our destination for the night, we headed back to the centre of Yirgacheffe to take the road to Guji. We were met by a driver for METAD, a large exporting company and all bundled into a single four wheel drive truck. There had been rains the day before and there were reports of the roads being damaged. It was definitely a bumpy ride and it was amazing to see the huge lorries carrying coffee towards Dilla, making short work of the roads which we were bouncing around on. After a couple of hours drive it was getting dark and we reached a point where we had to continue on foot. Out of nowhere a small group of local children appeared and escorted us the rest of the way, waiting for us at the gate of the Guji Buku washing station, to guide us back to the vehicle once we’d finished looking around. There was some steep terrain to tackle on the return journey and we had to exit the truck several times so it could navigate the soft earth on the roads.

Workers in Hambella, handling freshly arrived coffee cherry at night

We arrived late in the evening at one of METAD’s washing stations in the Hambella area of Guji and after eating a much needed meal, we headed down to the wet mill and saw some fresh coffee cherries being processed. Coffee is usually processed as quickly as possible after harvest to avoid any problems with mould or ferment and the processing went on way into the night. The mood was buoyant despite the time and the workers were singing and laughing as they emptied the bags of cherry into the silo where it was slowly fed in to the mechanical demucilager. This piece of equipment removes all of the mucilage using friction and means that the fermentation process is not required. After the pulp and mucilage are removed, the coffee is washed and then moves straight to the raised beds to dry. This allows for larger volume of coffee to be processed much quicker and helps to avoid a lot of issues which can arise through fermentation.

Once we had finished breakfast we explored the luscious, green, forest nursery next to the washing station before heading out to meet Abiyot, founder of Buno General Trading who manage several natural processing sites around Guji. Our final day in the field was spent visiting sites at Mansa, Bobea, Halaka and Goro, meeting some smallholder farmers who were local to each and checking out their coffee growing. It was amazing to see so much diversity in the varieties grown, many having different names depending on the local dialects.

The last two days were spent cupping through samples at Falcon and Siz Agro’s offices in Addis Ababa. The bustle and concrete of the city presenting a stark contrast with the palette of natural tones we’d become accustomed to over the previous week.

This trip was an amazing experience, visiting first hand some of the exotic sounding places we regularly see on coffee labels. One important thing which we took away from this experience was that the larger, privately owned companies we visited were really investing a lot into their local communities through infrastructure projects, school building and support for their farmers. It definitely made us more aware of how we purchase coffee from this unique origin and we have begun some business relationships which we hope will continue for many years to come.

Chirinos is one of the seven districts of the San Ignacio province, north of Jaen. This remote mountain region is where the mayor of San Ignacio hails from and it’s thought that this is the reason why more government money has been spent on improving infrastructure for the area. Concrete roads and electricity are common here and the town centre boasts a bank and other local amenities which make this an ideal central hub for many local cooperatives and exporting companies which serve the district.

Our first visit to Chirinos was to meet some producers who Falcon work with. Due to the proximity of the local cooperatives very few producers from this area consider it worth the effort of transporting their coffee as far as Jaen despite the higher prices and instead sell their parchment locally. Judging by the enthusiasm and obvious sense of pride in their work from these excellent producers it was clear that they are wholeheartedly committed to the relationship with Falcon and the higher prices they achieve are inspiring them to continually improve what they do.

The first producer we met was Herminio Romero Ramirez in a village called Los Cuyes (translated as “the guinea pigs”) which was divided into two areas, Las Pirias and Alto (high) Pirias. We were given a tour of the drier and wet mill where we were treated to a processing demonstration and Herminio explained how pleased they were we were to be receiving visitors and how the high prices Falcon were paying were enabling them to reinvest in their facilities. We had a great walk around his fields before heading up the hill to Alto Pirias to meet Graciela Espinoza and see her recently built drier, which has enabled her to produce some amazing naturals. Just across the road we met Juan Espinoza who treated us to a delicious stew in what turned out to be an old shop, complete with seemingly random dusty relics on the shelves.We rounded off our day with a visit to Eli Espinoza Soberon who showed us his amazing drier and wet mill despite the dark.


Our remaining time in Chirinos was spent with Thomas, a coffee consultant who works in Mexico, Guatemala and Peru, helping smallholder producers improve their practices and connecting them with roasters. In Peru he works closely with Finca Churupampa, an exporting company who provide agronomic support, transportation and organic fertilisers for local producers.We stayed on their idyllic farm in the guest houses they built for seasonal workers during harvest time.

The second half of our trip began with being invited to join the judging panel for the Chirinos quality competition. We spent the first day cupping through and scoring the 48 submitted lots which made it through and on the second day the top 14 were cupped and scored again to determine the winners. The whole town was in full festival mode with a huge market of street vendors selling clothes and local delicacies. The competition culminated in an auction which took place on a stage in front of what seemed like the whole town. There was a palpable sense of excitement as bids were cast and lots were won by the buyers who were present. Only the top three lots actually achieved vastly inflated prices and one of the lots which we won ended up closing at a price which was less than could have been achieved outside of the auction for a lot of that quality so we agreed to pay a premium on top of the auction price. Whilst these types of quality competition do inspire people to improve their quality, the flip-side is that they can actually give producers unrealistic expectations as only the very top lots sell for many times their market value and achieving less than the market value for a lot which places fifth for instance can have a profoundly demotivating effect.

We drove out to Pacasmayo to visit the farms of Rodrigo Goicochea and Ana Adelita Montealbán. The area is high in the mountains at 1,900 masl and upwards and has so much potential for great coffee but some improvements are still needed for some of the processing facilities and practices. Ana showed us a huge area which was being dug out where she was planning to build a new drier. We shared some food with the family whilst Rodrigo regaled us with tales of his legendary father and hidden treasure in the mountains.

The next day we headed to El Corazon to visit Fidel Huancas Huancas, who produced many lots which had stood out during our time cupping at Churupampa HQ as well as one of the competition lots which we won at the auction. His farm is located at around 1,900 masl and he proudly showed us his solar drier, in which he closely monitored the temperature and humidity. Afterwards we checked out a couple of his fields and saw that he had remote processing setups in a couple of them. These consisted of a de-pulper, fermentation tank, composting area and raised African beds for drying. As the fields are far from his house, it makes sense for him to start processing there and transporting parchment rather than carrying the extra weight of intact cherries. In addition to his two fields, he is renting a third which he pays for in coffee and is hoping to be able to purchase soon.

After checking out his super healthy Caturra and Bourbon trees we headed back to the house to see his drying house and storage, then shared a delicious meal which contained the best fried potatoes we tried in the whole trip. Fidel had such a lovely unassuming way about him and was really warm and humble. We’re really happy to be working with him and his processing is impeccable.

On the way back to Chirinos, we dropped in to see Clever Acosta who was excited to show us his experiments. After a walk through his beautiful fields and a look at a 1,000 year old endangered tree on his property, he showed us his impressive wet mill and drier where he had some hydro-naturals and experimental honey processes drying. Clever has also built his own cupping lab complete with a de-huller and sample roaster which he uses to assess his own lots and improve his skills. It was amazing to see someone with so much passion for quality and enthusiasm for experimentation.

We spent a lot of time cupping through lots from producers in Pacasmayo and El Corazon to find coffees suitable to blend together for our CONNECT espresso and selected five producers whose cup profiles fitted our brief. We are hoping that the relationships we have forged with these producers will be ones which continue to develop and strengthen over the coming years.

Peru is an origin which we had wanted to visit for the last few years as the coffee industry there is improving really rapidly. The potential for quality is great as they have really diverse micro-climates and high altitudes. Until recently, Peru has been known for cheap, high volume, commonly organic certified lots which have been staple blenders for many. Nowadays (as producers have realised that they can achieve higher prices for better quality coffees), more attention is being given to processing with a focus on improving drying practices which is essential for stability and longevity.

We spent the first few days of our trip spending time with our good friends at Falcon Specialty, Peru. The last couple of years have seen them developing their own exporting business there in an effort to improve the quality of the lots which they can source whilst ensuring the producers are paid fairly for their coffees. As well as paying above the market average for coffee, Falcon also supply agronomic assistance and processing advice. The amount of effort which they have put into this business in Peru has really paid dividends and they have built some amazing and trusting relationships with some excellent producers who we were privileged to meet.

Falcon’s operation is based in Jaen which is a town and province in the north of Cajamarca. Driving along the main road from the airport it’s obvious how important coffee is to the area as there are countless export warehouses here and you can see coffee drying on tarpaulins on nearly every available bit of land.

The warehouse was buzzing when we arrived, with producers waiting to submit their coffees. The process is really thorough and they aim to pay producers on the same day if possible.

  • Producers deliver bags of dried parchment if washed or dried cherry if natural
  • Each producer’s lot is weighed and representative 400g samples are taken from each bag.
  • The samples are milled and graded - only accepted if 11% moisture and under and free of aromatic taints
  • Defects are counted and weighed and the expected milled yield is calculated by subtracting it from the weight of the milled coffee
  • Samples are assigned codes and then roasted, cupped and scored immediately in the lab on site
  • Only coffees scoring 83+ are purchased and producers are paid a base rate which is twice the international market average and then a premium for quality, based on cupping score

    The warehouse was really well organised and we spent a lot of time here with the lab team, cupping through some rested micro-lots and also a lot of the new arrivals to get a sense of the quality of lots which were being submitted.

    On our second day we headed north-west of the town of Jaen to visit producers in the Huabal district. This area has very poor infrastructure and had little in the way of running water and electricity. We were welcomed by Saul Menor and his family along with Elizer Dias Dias who owns fields adjacent to Saul’s. After an amazing meal of root vegetables, eggs and home-made cheese we roasted some of Saul’s coffee in a pan and brewed it before making our way into the fields to see the trees. There was a fair amount of sickly looking Catimor present which the farmers were quick to point out was picked and processed separately. After widespread issues with leaf rust (roya) the government distributed Catimor seeds as these trees are highly resistant to leaf rust. Unfortunately, as well as having a comparatively poor cup profile, this variety is unsuitable for the high altitudes of the Peruvian mountains and all of the producers we met were either in the process of, or had completely replaced these trees with more suitable varieties such as Caturra, Bourbon and Gesha.

    We also met Nelber Aravelo, a young farmer who is in the process of planting his newly acquired fields with some great varieties including some really healthy looking Gesha from his nursery. The micro-lot which we cupped back in the lab from Nelber was full of character and super sweet with flavours of Turkish delight! Can’t wait to try more of his coffees next year.

    Much further North in a District of the San Ignacio Province called San Jose de Lourdes is the area of El Diamante. The area is much greener and more forest-like, standing in stark contrast to the exposed hills of Huabal. Here we visited the farm of Don Elvis. A young producer who has aspirations of success in the Cup of Excellence competition. He is also working part time in the lab at Falcon to learn as much as possible about cupping and how processing practices affect the cup profile.

    His fields were rich in bio-diversity and almost jungle like. Making our way through the undergrowth we saw some incredibly healthy Bourbon, Caturra and Maragogype trees and some incredible views across the mountains.

    Elvis showed us his processing set up and wooden fermentation tanks. Apparently, the wood can trap beneficial bacteria which contribute to the microbial activity during fermentation. Seeing the fastidious attention to detail which Elvis applies to his processing and drying, it’s little wonder that his coffees are so tasty.

    After the tour of his farm we headed to his mother’s house where we were treated to coffee blossom honey, fresh from the hive and whilst we waited for another massive meal to be prepared we milled and roasted some of Don Elvis’ Caturra which secured him 7th place in Cup of Excellence last year.

    Half way through our trip, we are incredibly inspired by the producers we have met so far and the level of enthusiasm for improving quality across the board and the economic advantages that this can provide.


    When we were throwing ideas around the table at the very outset of this company it was pretty much a given that our house espresso would be a blend. That’s what everyone does, right? The more we thought about it, the more we started to question it.

    The first issue for us, which is what we love about specialty coffee, is that the lots we buy are all tasty as hell and reflect the hard work that the producers have put in at origin. Why would we then detract from that by blending them with other coffees?

    Another issue is with consistency in the brewing. Even with a simple 50/50 blend it is unlikely that many shots you pull will actually be representative of that ratio, meaning it’s harder to get consistent flavour. Espresso is already incredibly complex with many variables affecting consistency. Why add more?

    There are some good reasons to blend. If, for instance, you want to create a product which has a consistent flavour profile despite seasonal component changes. As coffees age and start to show woody flavours you can switch them out for alternative components which fulfil that character. The more components you have in the blend, the easier it will be to keep it tasting consistent and have a broad sweet spot for espresso. This is an approach which is more relevant at scale (think huge Italian coffee companies) when you have customers all over the world expecting a consistent product that’s super easy to work with. In specialty we are more interested in celebrating seasonality and most peoples blends reflect that rather than doggedly aiming for a consistent cup profile.

    If you are blending for economic reasons and want to meet a certain price point then you could choose inexpensive lots which have complementary characteristics; one with body, one with sweetness, one with acidity etc. The problem is that when you start to buy better and better coffees they are inevitably more balanced and nuanced and blending them becomes a bit of a waste.

    Now, there is no denying that blending can be a fine art; just think of whisky blenders choosing from thousands of nuanced single malts to keep their product consistent. I just don’t think that many of us in specialty are really doing a good job of it. We are usually blending to meet a certain price point, in the best case combining flavours and characteristics to cover up what what each component may be lacking, or at worst throwing coffees together because they meet the right price and volume requirements. Neither of these is an approach for us.

    In recent years, experimental fermentation has been a growing trend in the specialty coffee industry. We’ve all seen the terms “anaerobic”, “extended” or even “carbonic maceration” being used to describe the more controlled approach being championed by forward thinking producers and from the frequency of their occurrence It would be appear that these methods are becoming more mainstream.

    Before we look a little closer at some of the different types of fermentation being experimented with at the moment it’s important to learn a little more about what fermentation actually is and how it has been traditionally used in the coffee world.

    Fermentation is the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat. Fermentation plays a part in all methods of coffee processing but has a greater scope for experimentation and control within fully washed processes.

    The traditional purpose of fermentation as used in washed coffees is the removal of the fruit from the seed whilst attempting to prevent any colouration of the flavour of the coffee. After the cherries have been pulped they are left in a tank to ferment, sometimes with water, until the fruit mucilage surrounding the seed is loose enough to remove easily. Although the fermentation is only concerned with the fruit it can still have an effect on the seed. For example, if the fermentation is too long this can lead to over fermented or “winey” flavours which are undesirable.

    By definition, all fermentation is anaerobic because yeast and bacteria do not respire. When this term is used it is most likely to describe a process in which the oxygen has been removed from the fermentation environment. This could refer to something as simple as a fermentation under water or to a more complicated method such as fermentation in sealed containers, carefully monitoring and controlling the temperature and pH levels.

    The duration of the fermentation required to remove the fruit will vary dependant on the altitude, environmental conditions, the strains of naturally occurring bacteria etc. Some producers try to push this as far as they dare in order to add more fruit characteristics to the coffee. Get it right and you end up with a coffee which tastes like an exceptionally clean natural process. Leave it too long and you end up with a cup which is overwhelmingly vinegary. Some producers also extend fermentation due to necessity. If a days harvest is not enough to fill the fermentation tanks they will “top up” with the subsequent days pickings. Each days pickings increase the pH levels which allows longer fermentation times without the acetic acid produced by bacteria at a low pH.

    Carbonic maceration is a technique which is popular with the natural wine making community. Pioneered by Jules Chauvet, a winemaker trained in chemistry, it is widely associated with wines from Beaujolais. The sealed environment limits the introduction of new bacterias from the surrounding environment and allows for more control over temperature. Saša Šestić, a Serbian born Australian, was the first person to bring this process to the World Barista Championship in 2015. The coffee which he was using had been produced in Colombia with his collaborator Camilo Merizalde and the intention was to create more aromatic complexity and a lower concentration of acetic acid.

    Carbonic maceration setup at Finca la Senda, Acatenango, Guatemala


    Whole coffee cherries are loaded into a stainless steel container and sealed. This container is then flushed with CO2 from the bottom which forces all of the oxygen out through an airlock at the top of the container. The carbon dioxide gas permeates through the skins and begins to stimulate fermentation at an intracellular level. The entire process takes place inside each single, intact cherry. Once the coffee has reached its desired level of fermentation, the cherries can be processed via any chosen method as they are suitable for both dry and wet processes.

    Another new trend in coffee processing is using specific strains of yeast to further control fermentation. There is some incredibly interesting work being done by Lucia Solis, a microbiologist and winemaker turned fermentation designer and consultant at Luxia Coffee Solutions. She is championing the use of carefully selected, laboratory grown strains of yeast in order to either intensify or subdue flavours and also control the fermentation time to mitigate adverse environmental factors. She makes it very clear that as we look to industries like wine for new techniques that there are some fundamental differences in the products which should be considered. With wine, the fermentation is necessary, the grape juice must be fermented to create alcohol and flavour. We directly consume the product of that fermentation whilst in coffee the fruit mucilage is fermenting around the seed before being discarded whereas the seed itself is not fermented.

    There is no doubt that this is an area ripe for experimentation and can be beneficial to producers wishing to differentiate their products. However, these techniques can be comparatively labour intensive and there is a real risk of creating expensive products with no guarantee of a proportional increase in cup quality.