Even if you don’t roast coffee professionally, you may know what green, unroasted coffee beans look like. Colour, size, and appearance will vary, depending on the origin, the grade, and the way the beans were processed.
Just by looking at the coffee, you can’t tell how the coffee will taste, or if it will be any good. You can however tell something. Here is a shot of what coffee roasters like to see.
These are nice looking green coffee beans. They’re from a Nicaraguan coffee, in fact from a Cup of Excellence winner. It’s a pulped natural and as you can see there the beans still have some of the silverskin (“chaff”) on the beans. This may or may not be your favourite cup, but it is at least a coffee of a quality that will fetch a good price on the market.
Of course, not all of the beans in a bag will look like this. Some will invariably look like the ones in the next picture.
These ugly beans are what is known in the coffee trade as defects. Not every ugly bean counts as a full defect. For instance, three of the partially black beans in the picture above count as only one full defect.
The damage that make coffee beans defects can occur anywhere in the production chain. Some happen while the coffee berry ripens on the tree, some during harvesting, processing, storage, or shipping. The causes are multiple; insects, fermentation, moulds, poor handling, etc.
Defects don’t necessarily impart a bad flavour, but they can, and some can ruin a cup of coffee. If you like a good coffee, you’d rather not find one of these in it, or at least as few as possible.
It is common practice in the trade to take samples, and pick out the defects. The number of defects per 300g sample defines the grade. The lower the number, the higher the grade of the coffee, and the more expensive the coffee is.
Conversely, lower grade coffee contains more defects, and is considerably less expensive. Because coffee isn’t always sorted at the roasting plant, those defects will eventually end up in the package of roasted coffee.
Cheap beans are cheap for a reason, and that reason is partly because of the ugly stuff in the picture above. The question is, would you like to drink the coffee brewed from this?