At each stage of the coffee supply chain, the moisture content of a green bean must diminish – or the bean might become moldy, defective, and less valuable than before. Ensuring a bean dries correctly is essential in order to optimize its quality potential and minimize the chance of problems.
Roasters, near the end of the supply chain, have two tasks when it comes to managing moisture content. On the one hand, they must maintain the lots they store onsite within a narrow moisture range that is acceptable to their quality standards. They need to hold their coffee in this range for a period that will, hopefully, not be longer than a year.
On the other hand, and in the span of a few minutes, the roaster is responsible for driving the last remaining bits of moisture out of the bean via the application of intense heat and pressure. In these minutes, the coffee is exposed to the most energy it will experience at any point in the coffee supply chain and the roast is set up for either success or failure.
It’s easy to see why roasters should care about the moisture content of their coffee. But how useful is a number supplied by an importer, and how can roasters integrate moisture content readings into their craft? I spoke with Fred Seeber of Shore Measuring Systems, a supplier of moisture content meters, about measuring and making sense of moisture content in green coffee.
What Is The “Ideal” Moisture Content?
There is no official standard for ideal moisture content in green coffee, although the ICO recommends 11% as a good target. However, it’s commonly accepted that 10-12% is a reasonable range. Anything less than 10% is likely to result in loss of cup quality, while humidity at higher levels begins to create a risk of mold growth.
Yet a coffee’s humidity is not static. While the pre-export drying process drastically increases a bean’s stability, changes in moisture content are still possible. Environmental factors, such as being in a particularly humid or hot location, are a common cause of this.
Measuring Moisture Content: Is It Really Necessary?
Before getting into the technical details of measuring moisture content, it’s worth digging a little deeper into why it’s worth measuring moisture content. Knowing this will help you establish protocols suited to your specific needs.
For roasters of a certain scale, it’s simple: you pay for coffee by weight; the more water in that coffee, the more you’ve paid for water which you’re going to burn off anyway.
Thank you for allowing Accurate Weighing Scales (U) Ltd the privilege to serve you in advance.
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