Defects in Green Coffee Beans That Will Ruin Your Roast

Roasters that acquire only top-quality premium coffees may have only encountered faults on rare occasions. However, most roasters encounter them far too frequently, especially when dealing with “Specialty” grade coffees.

The truth is that any one of these dozen flaws will degrade the quality and flavour of the coffee you’re making. These flaws are both detectable and avoidable. The faults discussed in this article differ from the “formation” problems discussed in a prior article. With that in mind, we’ve created a simple, to-the-point description of what these faults look like, what causes them, and how they can alter the profile of your roast. You can also choose to use coffee roasters wa.

The Most Common Defects to Watch For:


Depending on the environment, faded beans might be caused by over-drying or excessive moisture absorption. In any case, fading beans are susceptible to environmental variables.

They have the effect of giving a bland roast regardless of the roasting profile. In the cup, the outcome is a mushy bean with musty and woody notes. Furthermore, the moisture loss percentage will be extremely high. These beans are light, whitish brown tint.

Coffee Beans usually cause them with a high moisture content (11 per cent to 13 per cent) that tend to dry out when stored in a warehouse. These beans tend to fade throughout the drying process and because they are not exposed to direct sunlight.

These beans are decaying and forming fungus inside instead of drying. These moulds cause the beans to dry out too quickly, giving them a light to greyish brown appearance.

Furthermore, the coffee can be badly damaged if wet or dry-processed beans are not properly exposed to sunlight at the appropriate point in the drying process.

Another reason for this is when coffee is over-hulled in a hammer mill. As a result of the outer cells being crushed and microscopic particles permeating the outer layer of the beans, the beans will have a dull colour.

Another element that contributes to coffee fading is older coffee that has been stored in a warehouse for two to three years or more, causing the beans to dry out, mould, and other bad effects.


The hue of these beans is a beautiful, shining gold. Mineral deficits in the soil are the cause (including iron).

When these beans are roasted, the cup lacks acidity and has a flat, harsh body and a bitter flavour. Furthermore, the colour of the roast generated by these beans will be rather drab.


These beans have sticky silver skin that is caused by either overcrowding or drought. These beans have a pale appearance, are tough, and have microscopic lines from the silver skin.

You’ll notice soft beans with a lot of chaff during the roasting process. The roast can cause undesirable cup characteristics such as extremely high grassy, hay, earthy, woody, greenish, and potato flavours.

Try to avoid any of these to have the best coffee. Coffee syrup are also helpful plus to make you get the best from your coffee.