Roasted Coffee Evaluation: Assessing Quality and Improving Profiles

Posted by Lauren Lathrop on

When you're roasting coffee for retail, it's not uncommon to find yourself in a positive feedback loop. Your customers (typically regulars and, if you're still a small business, usually people who know you personally) love your coffee and are excited to tell you so.

At the risk of bursting your bubble, what they may love is just a slightly higher-quality green that's been roasted within the past 2 months. A fresher roasted, slightly better green coffee will beat most large-chain grocery store offerings no matter who the judge is. 

Compliments and 5-star reviews are great. Generating positive impressions and having people recommend your product to friends and family is even better. But roasters who are looking to constantly hone and improve their craft need something different: critical evaluation. They are people who already know what they are doing well, they're looking for someone to tell them where there's room to improve. How to slightly tweak their profile to get to the next level, or how to streamline their roasting process to make it even more efficient, precise, and repeatable.

Luckily for them, we can be those critics. 

Mill City Roaster's Services

If you've spent time on our website, blog, or YouTube channel you're familiar with the many ways we help people become better roasters. We offer advanced data-logging software, hands-on roasting classes, custom space planning and venting solutions, and a library of curated and super fresh green coffees. Our goal is to provide everything that a burgeoning roaster needs to succeed.

One of the services we offer within the catalogue of Roastery Services is a product called Roasted Coffee Evaluation. When roasters are looking for actionable feedback on profiles they're currently roasting or developing, this is where they can turn. 

All we need to get started is about 300g of roasted coffee. We also ask for a printed or digital copy of the coffee's roast curve, as well as any information that seems relevant to our evaluation. Sometimes, people will send a coffee they're still trying to find an ideal profile for. Other times, it's a coffee from their regular production line-up and they can tell us what the intended brew method and tasting notes are. 

Steps of a Roasted Coffee Evaluation

Just like a good green grader, we begin our evaluation with quantifiable metrics. We first take internal and external roast color readings using our Lighttells CM-200 color analyzer. This gives us a general range of the roast level for the coffee, as well as an important metric: the spread between internal and external color values. More on that later. 

 Next, a quick visual assessment is completed to evaluate general roast uniformity and the presence of roasting defects. While uncommon, visual defects like cratering can immediately tip us off to potential issues with the profile. 

We set up a full cupping following our standard cupping procedure. As a rule, at least one member of the sensory team involved with the cupping will not know the coffee's origin (or blend components), roast color readings, or the customer's or roasting company's name. This approach helps us avoid unconscious bias at the cupping table and enables us to taste the coffee with an open mind. Although unconscious bias isn't always a bad thing, it can impact our perceptions of quality in ways that limit our findings. That's a larger topic for a future blog post. 

After the cupping, we calibrate our notes. This involves reading through all of our observations on the coffee's fragrance and aroma, flavor, acidity, sweetness, body, and aftertaste, and how the cup transformed as it cooled down. Our sensory team is well-calibrated, which means many of our notes will overlap and speak to similar experiences. Where we denote different experiences is where we work to come into calibration. This helps us provide better feedback to the customer. 

Recording Cupping Notes and Drawing Correlations 

Once cupping is complete, we take those tasting notes back to the computer and compile them in a full written report. Then, we compare our experience at the cupping table to the customer's roast profile. This is where the rubber meets the road in terms of how this service provides value to a roaster. 

Our cupping notes include everything that a customer might experience from a given coffee, but that customer may not be able to articulate what they like or dislike about it. That's because they're not trained in sensory evaluation. Learning to assign language and assess quality in flavor is a learned skill and one we've been practicing for over a decade. 

We can connect the cupping notes to very specific landmarks or inputs on the roast profile and clearly identify where flavors (positive or negative) are being created during the roasting process.

Looking back to the initial set of roast color readings and visual evaluation is another layer of context to explain how and why undesirable flavors may appear in the final cup. 

All of this is included in a written report along with recommended changes for improving the roast profile. This is the same type of feedback students experience when we cup coffee together during our Roasting 101 class, but it's a more focused, in-depth, and lengthier evaluation. 

For many roasters, just having a team of professional cuppers taste their coffee and send over tasting notes is a valuable investment. Being able to calibrate to experienced cuppers' flavor and aroma calls is a very helpful way to improve your sensory skills. Some customers may even use some of our tasting notes on their retail bags or product pages on their website (that's great!). But most people will focus on those recommended changes, and head back to their roasters with a better sense of direction and purpose. 

How to Start Your Evaluation

If this is a service you think might benefit you or your business, please get in touch. We have no requirements for how much you're roasting, what machine you're currently working on, how much experience you have, or where you are right now in your coffee journey. We love to help people understand coffee and improve their knowledge and skills. This is one of the many ways we've been able to do just that.

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