How to Read a Certificate of Analysis

A certificate of analysis, or CoA, is the document that records the measured quality of a green coffee lot. It is how you confirm, on paper, that the coffee matches what you contracted before you accept it and pay against it. A CoA does not replace cupping the coffee, but it gives you objective figures to check the lot against your spec, and it is one of the first documents you should ask for and read closely. This guide walks each parameter and shows you how to use them.

The parameters

Moisture content. The percentage of water in the green bean, usually reported as a percentage by weight. It matters because coffee that is too wet risks mould and quality loss in transit and storage, while coffee that is too dry can lose weight and taste flat. The internationally referenced range for export green coffee sits around 10 to 12 percent. Indonesian coffee processed by wet hulling often reads at the higher end of the normal range, which is a known characteristic of the method rather than a fault. Read moisture in that context.

Water activity. A measure of the unbound, available water in the bean, reported on a scale from 0 to 1. Where moisture content tells you how much water is present, water activity tells you how available that water is to support mould and microbial growth, which makes it a better guide to storage stability. Lower and stable is what you want. Specialty buyers increasingly expect water activity on a CoA alongside moisture.

Defect count and grade. The number of defects found in a sample, which sets the grade. In Indonesia, grade is assigned primarily by defect count under the national standard, with a cleaner count meaning a higher grade. The Grades page sets out the full scale and what each band means. Check the stated grade against your contract, and check that the defect count supports it.

Screen size. The bean size, measured by passing the coffee over screens with holes of graded diameter and reporting the proportion retained on each. Screen size affects roast uniformity, since beans of even size roast more evenly. A CoA will usually state the screen or the screen distribution, and a tolerance for how much may fall outside it. Match this to what you specified.

Density. The mass of the beans for a given volume. Denser beans are generally associated with higher grown coffee and are valued for how they develop in the roast. Density is not always on a basic CoA, but it appears on fuller analyses and is useful for matching a lot to a roast approach.

Cup score. For specialty lots, the cup score is the quality grade given by a trained taster, on the 100 point scale used by the Specialty Coffee Association. Coffee scoring 80 and above is classed as specialty, with higher bands above that. The score is the most useful single summary of cup quality, but read it alongside the taster’s notes, not on its own.

How to use a CoA

Read the CoA against your contract spec, line by line. The contract should state the target or the acceptable range for each parameter, and the CoA should fall within it. Where a figure sits outside the agreed range, that is a conversation to have before the coffee ships, not after it lands.

Know the difference between a pre shipment CoA and arrival sampling. A pre shipment CoA is drawn from the coffee before it leaves origin, and it is your basis for approving the lot to ship. Arrival sampling is done when the coffee reaches you, and it confirms that the coffee that landed matches what was approved and that nothing changed in transit. Both have a place. The pre shipment CoA protects you before the coffee moves; arrival sampling protects you after it arrives. For a first contract, plan to do both.

How IndoCasa handles this

We arrange a complete certificate of analysis at origin and, where you want it, an independent pre shipment inspection, so the figures you read are drawn from the actual lot about to ship. You approve against your spec before the coffee leaves Indonesia. The analysis travels with the document set, so what you read on paper matches what arrives in the container.

For how analysis fits the wider purchase, see How to Import Green Coffee. For the grading scale behind the defect count, see Grades. To discuss a spec, Contact Us.