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March | April 2020

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FEEDBACK LOOPA Dialog Between Roasters and Producers on Green Coffee Evaluation

A conversation between Trish Rothgeb and Luis Rodriguez Ventura, and featuring:

• AISLINN CULLEN customer relations manager for Melbourne Coffee Merchants, Australia
• TERE DOMINE coffee producer and co-founder of Kalsada Coffee, Philippines
• DR. MARIO FERNANDEZ technical director, Coffee Quality Institute, Portland, Oregon
• ETON TSUNO trader at Atlantic Specialty Coffee, San Leandro, California
• CAMILLA YUAN head roaster at Temple Coffee, Sacramento, California

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A FEW YEARS AGO, I contacted Luis Rodriguez Ventura, a friend and coffee producer based in El Salvador, to ask him about a green coffee defect I kept finding in the new season’s Central American offers. This defect didn’t really fit into the classification tool I was using, and I was a bit confused. The tool I use is SCA’s Arabica Green Coffee Defect Handbook, not only for training others at the Coffee Quality Institute’s Q Arabica Grader course, but also within the walls of my own small roastery in San Francisco. The question I had that day grew into a longer conversation, and now, both Luis and I will make a point to contact one another when we find something interesting in our green coffee.

The coffee world is changing, whether it’s due to climate change, processing trials, or new hybrid varieties. While change is exciting and brings new challenges and discussion to the table, we may find that the form the discussion takes needs an adjustment as well. Are we making progress when it comes to giving and receiving feedback between producers and buyers? The author Linda Lambert said, “One good conversation can shift the direction of change forever.”

The following is a conversation that continues today between Luis and me. We spoke over Skype and corresponded with email. In the process, I asked some friends to chime in with their thoughts. With so much to explore, it should be noted that this conversation is just a small selection of what we’ve talked about. We’re looking forward to having many more exchanges like this.

It’s important to remember that green coffee contracts are legally binding. Sometimes even a handshake contract or specifics statements during a verbal conversation can be considered legally binding. Purchasing agreements run the gamut from formal to informal, but ultimately, all of them rely on relationships. Any of the subjects we discussed here can be fully detailed within a contract (which is certainly recommended if circumstances warrant it), but a contract is not a conversation. A contract is in lieu of, or the result of, a larger dialog. For this piece, we wanted to focus on a few of the many subjects we could be discussing as buyers and sellers of specialty coffee and find ways to learn from each other. Hopefully we can go on to develop those strong, solid partnerships that everyone in the green coffee space yearns for. —Trish Rothgeb

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TOP ROW Trish Rothgeb, co-founder and roastmaster for Wrecking Ball Coffee Roasters in San Francisco. Luis Rodriguez Ventura, coffee grower and owner of CAFERIUM, a coffee consulting company in El Salvador. SECOND ROW Aislinn Cullen, customer relations manager for Melbourne Coffee Merchants, Melbourne, Australia. Eton Tsuno, trader at Atlantic Specialty Coffee, San Leandro, California. THIRD ROW Camilla Yuan, head roaster at Temple Coffee, Sacramento, California. Tere Domine, coffee producer and co-founder of Kalsada Coffee, Philippines. Dr. Mario Fernandez, technical director, Coffee Quality Institute, Portland, Oregon.

TRISH: What’s the most common feedback that roasters and producers exchange regarding green coffee?

LUIS: In terms of feedback, most of what we normally get is the relation between the Pre-Ship-Sample (PSS)—or offer sample—to the actual arrival in terms of cupping scores. These variations are typically minor and do not cause an issue; most buyers understand that there are many factors that can affect a landing coffee’s quality apart from farming or processing practices. Dealing mostly with specialty coffee exports, I tend to get very little feedback regarding physical characteristics, screen size or defects, however sometimes we get moisture readings [and] very rarely water activity (aW) feedback …[sometimes] quakers, but again dealing with specialty coffees this tends to almost never appear to be an issue. I believe due to a prep that normally goes from zero to less than five secondary defects, there is very little to add from [roasters’] side here.

ETON: We send physical analysis of moisture content, water activity, density and cupping notes with every sample approval/rejection. This is all part of our quality assurance protocols to ensure coffee delivered is in fact the coffee quality contracted and that origin is calibrated with our findings. If there is an issue with the coffee, we will send defect count, screen size distribution and often an ultraviolet (UV) light analysis as a photo or video as well.

TRISH: Ultraviolet light analysis is an interesting development as a standard by which to measure quality. I say “interesting” because I don’t think everyone’s clear about what is glowing under the light. Nevertheless, I’ve heard of more than a few roasters drawing their producing partners’ attention to it. The assumption is that green coffee that glows under UV light will be of a lesser quality.

MARIO: The glow under UV light is likely related to the metabolic byproducts of processing. So far, it seems related to 1: beans with dead/ejected embryos, 2: beans intensely fermented, and 3: wet-hulled process, but not always.

LUIS: Water activity is most definitely a great tool to make decisions, but I think there is not enough information available to make a solid statement of how, where and when to take this measurement.

TRISH: What I don’t understand about water activity and moisture content [is how] it relates to storage, shipping and location.

LUIS: I have a hard time believing my conditions in the warehouse in El Salvador are the same as my lab or the lab of my buyer, or the warehouse of an importer in Oakland for two months, or the warehouse of a buyer in Sweden during January. Even if I get feedback from the buyers, most growers can’t spend $2,000 on a water activity meter. Don’t you find fascinating this topic (aW)? How much we can still learn and apply in our industry?

TRISH: I think most roasters who take these readings, or run through a green coffee evaluation upon arrival, are trying to identify the lot more than anything else. It’s not typically going to be mentioned during cupping. In my mind, this is where it could evolve.

AISLINN: If we get a water activity reading that is particularly high on PSS or landing, we also flag the coffee as potentially having an issue down the track and instruct our customers to use the coffee quickly. We find the water activity and moisture activity readings useful but not always directly correlated to the cup quality.

LUIS: Obviously with some exceptions; there was one time that I got a sample rejected by aW and moisture content, so I resampled every small day lot and isolated those with better aW and moisture. Two small day lots out of 11 were throwing off the readings, and that meant a huge difference in price. 

Having said that, there have been times where I’ve received very good reports on offer samples and then, because the coffee arrived similar to the offer samples, I didn’t receive any additional feedback besides the follow-up email saying everything seems to be fine (or perhaps a particular sample lost some points due to delays in shipping or warehousing issues).

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Coffee cherries in Peru. Photo by Mark Shimahara


TRISH: Do you trust our green coffee grading or evaluation? To be specific, specialty small-sized artisan roasters like me?

LUIS: To be fair, I will tend to believe most small roasters are far more interested in getting their coffee cupping nice rather than having a full physical analysis on samples. Having moisture meters, screens and water activity meters is sometimes not common, and also a complete protocol for sampling a whole lot and getting a representative sample of the whole lot seems to be super rare [at] most smaller roasters.

Do you think specialty roasters from small to medium size have specific protocols to test samples on arrival, both for physical analysis and grading roasted and green?

TRISH: I think that we can rest assured that most of us—even the smallest-scale roasters—are tasting the arrival coffee and comparing it to the offer sample. We might not all know enough to compare physical defect from offer to landed, but we definitely taste. I think it’s worth asking about, though. A producer should be able to find out how well the coffee traveled and kept after it left them. Mostly for moisture and aW, right? How often do roasters mention a specific physical defect, and can these defects be traced back to impacts to cup quality ... on your table? On their tables?

LUIS: I truly believe El Salvador has some of the best processors of green coffee, due to the know-how and structure of exporting mills we have. We have good equipment and skilled people behind them. 

I haven’t gotten feedback about a particular green defect from buyers. Recently, we might have had some problems [with] some lesser-known defects such as escarcha, or frost damage, as it doesn’t seem to affect the cup if the occurrence is not higher than 10 percent when it appears in its lighter form. Some might disagree, but this is the beauty of coffee.

TRISH: This was one subject you and I began talking about years ago—frost damage—which does not appear on the SCA green grading schedule of defects. We found it in other resources (Wintgens, page 765; “Guia de Factores Que Inciden en la Calidad del Café” 2015, Plataforma Nacional de Café Sostenible–SCAN Guatemala). It can and has been misclassified by Q Arabica Graders as the partial sour defect, which is much worse in the cup than frost. This is a potentially dangerous time for our specialty tools like the grading handbook. If we misclassify because we are not talking to our partners about the specific defects that we think we’ve found, we will unfairly punish producers. 

LUIS: There are problems that might not be obvious in green but might be problems you can see from your roastery. For example, we have had precious cherries entering the mill and [were] surprised that the cup of it is just okay coffee, perhaps even with some quakers in it, but how can this be possible? Well here is where diseases and weather might be playing a bigger role, sometimes (various diseases) and rain, or lack of rain at some point of the curve of ripening, might affect the development of the seed, creating some not-obvious problems. As a result, you might get some infamous “semi-quaker”-looking roasted coffee.

TRISH: Yes, I think that we have a limited understanding of defects like quaker (SCA Arabica Green Coffee Defect Handbook). Can our partners find the causes? Is a schedule of defects on a list enough of the story? Shouldn’t we open a discussion about each defect we find in order to get all the information we can? I know that quakers are not always the result of unripes. I’ve seen quakers from slight and severe insect damage. I’ve even seen when a sprouted embryo is to blame.

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Beans affected by escarcha, or frost damage. Photo by Luis Rodriguez Ventura


TRISH: Do your customers/partners ever ask you to eliminate particular defects?

LUIS: Well, yes, the obvious primary defects according to SCA green grading handbook, but I’ve had a request to try to separate all the triangles (Wintgens, triangle defect, page 762) to make a lot out of it … go figure, I could not figure out how to do it efficiently, so I bailed out on the idea!

TRISH: Separating triangles? That sounds like someone wanted a novelty coffee for marketing reasons. I wonder how much they would have paid you for your trouble!

TERE: Recently, there have been requests for us to do specific processing for certain buyers (anaerobic, carbonic maceration, etc.) and to make it exclusive to them. Other clients prefer a specific variety that’s not common in the Philippines. So far, there aren’t any price discussions, and we keep the same selling price across clients.

TRISH: From what I understand, anaerobic fermentation (fermentation without exposure to oxygen) has evolved from simply submerging parchment under water in tanks to a completely closed chamber or vessel during fermentation. Carbonic maceration is when the chamber eventually fills with carbon dioxide byproduct from fermentation. This procedure may require new and different pieces of equipment, as well as significant changes to the processing timeline and general operations on the farm.

LUIS: Do you think most coffee buyers understand what is implied by clean defects at origin? And do you believe there’s an understanding of how these byproducts will affect the end result of their partner’s income? Are ratios from cherry up to exportable green clearly understood?

TRISH: No, I don’t think it’s widely understood by roasters at all. If we spend most of our time talking about cup quality and nuance, which seems to be the most popular subject of conversation between roasters and producers, we lose the chance to learn some of these important foundational facts about production.

LUIS: At some point, and this has not to do with defects but rather some other prep specs as screen size, I believe this requirement has eased over time also due to misunderstanding that a screen size of 15 was not good and also related to the lower prices in the past years.

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From left: Gabriel Borges and Joao Jarduli cupping at Cafebras, Brazil. Photo by Trish Rothgeb


TRISH: From your perspective, what’s the feedback your partners seem the most interested in besides cup quality?

ETON: This depends on the origin operation, but for us it is generally moisture, water activity and ultraviolet light fluorescence—and how all those things relate to each other can ultimately comment on the longevity and stability of any given coffee. Defect count, type and screen size seem to be of less interest as these tolerances and standards are already clearly defined, noted and standardized in the industry.

AISLINN: We send feedback on where the coffee has sold, how quickly it has sold and what purpose customers are buying the coffee for, which suppliers find very useful. We try and provide as much context for the Australian market as possible, including putting together a presentation showing pictures of the coffee here, retail bags being sold, Instagram posts by customers, photos of events we have run—this can be very meaningful for the producers, especially the ones who are not active on social media. Social media has been so influential in connecting producers to our customers, so we also make a point to tag producers and suppliers wherever possible.

CAMILLA: I think that cup quality feedback to producers is important because it’s a good benchmark on their product, but I think another essential piece of feedback is how their coffees are used in real-time, in cafes. The feedback on how their work is being showcased across the world is something that is just as valuable as cup quality.  

LUIS: Regarding green grading and classification of particular defects (or their absence), do you think we as growers benefit more from feedback about numbers or the reasons behind their appearances and ways to avoid them? And do you believe feedback also should be tied or translated to actual actions from the roaster helping the grower to overcome these problems? 

TRISH: I think growers benefit in the sense that they can easily find out what is important to their buying partners. Creating that feedback loop is important, but are we really making the coffee better? When we tell you about defects, we really should be asking you to give us context.

Tools like moisture meters and green coffee defect lists have been developed over the last couple of decades to help us measure quality. But after all the examinations have been done, what have we learned about the real costs and challenges around producing the coffees we buy and sell? We can and should continue the best practices that work toward our goals. In fact, Luis and I have offered you some bullet points to consider here. These ideas are meant to urge you to go beyond the commonly held notions of proper procedure. There’s so much to learn through an active feedback loop, it’s just a matter of starting the conversation.


  • Use common language and mention the protocol you are using for grading; avoid separating beans just because they look ugly.If defects are not in the charts, they should not be counted as defects. If you can’t name it, ask your partner.
  • Good-quality photos are a great tool when buyers send them to growers. Also, group the defects so you give us enough examples of them.
  • Get a sample that is representative of an entire lot—not a single bag or two—and then grade it.
  • Make sure you fully understand what it takes to remove the defects you are not willing to accept and make sure the grower has the tools to get rid of them.
  • When you give feedback, make sure that you understand the realities of each grower and what it takes to make such changes, and ideally be willing to put the money behind this feedback. Remember, each pound of coffee not sold is a problem on the grower’s side.
  • Many defects are generated by agronomic conditions (unless there’s some lack of knowledge in the processing side that exceeds the common norms or standards), and most likely are not controlled by the grower. Every year is different, and that is part of the risks and benefits involved when developing relationships at origin.

Tools like moisture meters and green coffee defect lists have been developed over the last couple of decades to help us measure quality. But after all the examinations have been done, what have we learned about the real costs and challenges around producing the coffees we buy and sell? We can and should continue the best practices that work toward our goals. In fact, Luis and I have offered you some bullet points to consider here. These ideas are meant to urge you to go beyond the commonly held notions of proper procedure. There’s so much to learn through an active feedback loop, it’s just a matter of starting the conversation.


  • DO create a consistent and repeatable protocol for green coffee evaluation coming into your roastery as an offer, a pre-ship sample, and the landed representative sample. 
  • DON’T assume that the aW is a stable reading that will agree with what your producing partners recorded. In fact, know that it’s likely to change, especially across different climates and over time. DO work with producing partners to understand a window of variation for aW, and DON’T assume all of your coffees will follow the same parameters. 
  • DO practice green grading for all your landed lots and pay special attention to the frequency of defect in the cup quality for any lots that classify as below specialty. Assuming you bought that coffee for its great nuance and flavor, there is potential to make it even better. 
  • DO make sure your tasting notes are aligned with your producing partners’ notes. Ask questions about terms they use that are not familiar to you. Make sure to welcome comments on your tasting notes. Actively build bridges between any language barriers and cultural gaps that may exist.
  • DON’T assume that the cupping of the landed sample is the final assessment on that coffee. It will change while in your possession. Make notes for your partners throughout the life of the coffee, but don’t limit them to just cup quality.  
  • DO begin the conversation about price adjustment if you’re interested in processing experiments or separations. It’s on you to drive the project you want to see, and that includes price you will pay and agreement to buy your own trials.
  • DON’T assume the challenges you face with a coffee are the fault of the green product or the producer’s work. Isolate variables on your side regarding storage, inventory and roasting before inquiring further back through the value stream.


TRISH ROTHGEB is co-founder and roastmaster for Wrecking Ball Coffee Roasters in San Francisco. Her experience in the industry spans more than 30 years as a coffee roaster, taster, green buyer, frequent lecturer at conferences, and teacher of all things coffee.

LUIS RODRIGUEZ VENTURA has been working in the private and public coffee sector in El Salvador for 20 years, with 10 of them as a coffee grower and owner of CAFERIUM, a coffee consulting company. With a background in marketing and economics, Luis is a Q Arabica Grader and Q Processing Professional. He is also the quality control advisor at El Borbollon mill.

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