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Green coffee quality and its impact on the supply chain is getting more and more attention. In 2018 alone, hundreds of publications addressed topics like how altitude affects the composition and quality of green coffee, what common roasting defects exist in coffee, or how some processing methods influence the final quality of coffee. It’s clear that green grading, also known as physical analysis, is a topic whose time has come and one everyone across the supply chain needs to understand in increasing detail.
We all know green grading happens at set stages in the supply chain. This model has worked well for many years. Why the sudden push for more players to visit this process? Why should you analyze and grade the green coffee you buy when you’ve been working with the same (or a new well-established) importer over time? Putting your trust and faith in the importers you work with can save time and money. Over time good importers will understand your needs and flavor profiles. They’ve green graded for you and shared this information with you. So, as a buyer you know exactly what you get when you buy a Kenya AA. Most likely, you’ll do a quick visual sense check once this Kenyan coffee arrives at your warehouse but that’s often all. It’s been normal to make assumptions about the green coffee and its assigned grade before you’ve received it. Plus, if you can tell that you’ve got an excellent lot of green coffee by visually looking at it, that’s a big time saver. However, there is a lot more you need to know about your green coffee that a visible inspection will miss. Also, if you know more about your green coffee, you can be more confident in your purchasing decisions and the quality of your end product. Why?
Understanding the impact of everything from screen size, to moisture content and water activity, and how to roast accordingly, takes time. This is time well spent as green coffee is your critical starting point and has the biggest impact on your cup. As our good friend Geoff Watts, VP of Coffee at Intelligentsia, has put it: “our most important limitation as a roaster is the quality of our ingredient.” In other words, understanding your raw product can give you insights into how the coffee will roast and how it will cup.
There is always the risk of defects in an agricultural product. It’s common knowledge in the industry that the green coffee’s physical properties influence your roast profile. While some physical defects impact your roast process, other defects will only have an impact on the quality of the cup. This also means that it’s impossible to take a mediocre-quality green coffee and turn it into an excellent cup, no matter how great your roasting skills are.
Knowing and collecting key details about your green coffee from the start is essential so you can easily trace it back and compare your cupping results overtime. It also means that you are more likely to understand changes in your green coffee. This will help you maintain and improve quality as a buyer. If some defects obviously increase while others decrease, you can give back this feedback to the farmer to help them improve their harvesting or processing methods or maybe validate if they’ve recently made a change to their gear or methods. Everyone in the coffee supply chain benefits from measuring, tracking and sharing all this green coffee information.
Defects in green coffee will always exist and need to be tracked. Recently, the specialty coffee industry has shifted more research to physical attributes well beyond black, fungus, sour or insect damage. For example, water activity can help you to identify how safe your product is, i.e. free from bacteria, how stable the coffee’s shelf life is and how it will react to the heat in the drum. Some of these physical attributes, like density and water activity, sound like complex processes. But measuring and collecting those metrics is quick and is getting less inexpensive.
This is one of many reasons Cropster has increasingly put green coffee quality at the center of new product initiatives. Leading coffee businesses are demanding this information be available across their production. As a result, green grading is now a core part of Cropster for all customers regardless of size. Why has this demand increased? As businesses have begun to collect this information they have learned that physical analysis/green grading has limitations when measured occasionally. They want to ensure it is consistently tracked to improve quality and their internal processes like buying, roasting, and blending.
Water activity is a terrific example of this. If you capture water activity over a green lot’s life cycle, you will see changes over time and this will affect how you design your roast profiles. Beans with a lower water activity lose moisture more quickly, which will have an impact on your roast duration and how you’re going to apply heat during the roasting process. This also means that when you plan to roast a coffee over the course of several months, this coffee will begin to mature and its physical properties will change. Knowing what to measure and how this data influences your roast profiles over time is an essential skill a roaster needs. Simply put, it is a key to consistency. Through measurement and analysis Jen Apodaca from Royal Coffee’s Crown has shown that once a green coffee matures it loses some of its acid structure, which requires you to adjust your roast profile.
This leads to a key question: when and with what frequency should you analyze and grade your green coffee? Most businesses grade their green coffee when it hits the first warehouse but a solid starting point is to collect this data systematically. One key factor is understanding how long you plan to store the coffee, the conditions in the storage area, and in what type of packaging the coffee will be stored. If you plan to roast it within a couple of weeks, it’s unlikely that you need to do multiple green grading/physical analyses. If you have larger green coffee lots in multiple locations and changing storage conditions, measuring and collecting physical attributes more often makes sense and will help deliver results during roasting.
You may need to document that you’ve evaluated green coffees for customers in your supply chain, e.g. when you roast for another company or when you suspect that a supplier has delivered a lower quality coffee. Our roast expert and product manager, Chris Hallien, said that, in his view, it is incredibly advantageous to have your own specifications for each of the green coffees that you purchase. In addition to this individual criteria, there are universal specifications that can be adopted for all green coffees, such as a lower and/or upper limit for total moisture content and water activity measurements. He also added that there are several different classification standards within the industry. It is important as a roaster to understand how the green coffee that you buy has been classified in order to know what to expect in terms of overall quality as practices can differ from country to country.
Bottom line: all the physical properties of your green coffee have different impacts. Some might influence your roasting process, while others have an impact on the flavor in the cup. Roasters need to understand what and how to measure in regards to green coffee quality as this will help them become better roasters. In other words, the roaster who knows the most about his raw ingredient, can work better with it. And in the end, produce a better cup of coffee.