What Are Common Coffee Faults?

What Are Common Coffee Faults?

Not everything is perfect, so it's no surprise that the same concept applies to coffee as well. Typically, you never experience coffee faults because these defects are typically detected and eliminated way before it reaches your home or favorite local cafe.

The coffee faults that manage to slip past the quality test will end up in your bag of coffee, which is the last thing you want because nothing tastes worse than a cup of coffee that came from faulty coffee beans.

A general rule of thumb you should apply and stick to every time you open up a new bag of coffee is to inspect the beans for any faults. Keep reading to inform yourself on some coffee faults to make a note of before you continue to the grinding process of making a cup of coffee.

Green Coffee Beans

A popular misconception people have about coffee beans is that they grow to feature a brown or black color, but this is entirely false. Coffee beans only appear brown or black after they have been roasted, so, naturally, coffee beans feature a green color that may develop faults that will affect the overall quality of a cup of coffee.

You'll know your green coffee beans aren't suitable for consumption when you notice a hint of discoloration around parts of the coffee bean. This inconsistency in color results from the oxidation that occurs as a response to the damaged areas of the coffee bean.

Green Coffee Beans

If you continue to roast discolored coffee beans, you should expect them to roast at an uneven pace as well as age at increased levels, which is guaranteed to make a cup of coffee taste nothing like it’s supposed to, which isn’t a good thing.

You can pinpoint discolored green beans when you see a deep blue, dark brown, or even black spots surrounding certain areas of the pre-roasted coffee bean.

What Causes Discolored Coffee Beans?

Many things could go wrong during the coffee bean growing process to result in a green coffee bean that has hints of brown all over it. Ultimately, the more experienced coffee bean grower will know all the conditions that guarantee a high yield of perfectly healthy coffee beans.

When you harvest coffee cherries too early, you run the risk of picking coffee beans that haven't fully matured, so you should expect some discoloration to form. The same applies to cherries that have fallen from its tree since they are already dead, which isn't suitable to continue with the roasting process.

Coffee Beans

Never forget that coffee beans are susceptible to outside temperatures, so applying incorrect levels of water and heat at the inappropriate times will result in discolored coffee beans, which is synonymous for unusable coffee beans.

Certain factors that cause discolored coffee beans can be avoided since they involve faulty fermentation, over drying, and incorrect washing. All these three actions combined will result in green coffee beans that feature a rusty brown color to them that won't respond well to the roasting process.

A Look At Common Roasting Defects: Roasted Coffee Beans Faults & How To Detect Them

Coffee faults particularly caused by the roasting process will affect the overall flavor of the coffee, and you have the roaster to blame for this. Roasting process malfunctions result in your coffee gaining a unique flavor that you can quickly pinpoint when you cup your roast.


A relatively common roast error that occurs when the temperature is too high, and you continue the roasting process. Since coffee beans are sensitive to the surrounding temperature, exposing it to such high temperatures will leave burn marks at one end of the coffee bean.

Tipping When Roasting Is Bad

The burnt mark on a particular end of the coffee bean will have your coffee taste like cereal, which is an undesirable taste that shouldn't be associated with a cup of coffee.


The coffee roasting process is a highly precise process that can go wrong if you don't follow the guidelines dictating particular temperature levels and volume. When you first begin a roast, if you were to introduce the green coffee beans to a setting that's either too hot or too loaded with beans, you should expect scorching to occur.

Scorched Beans On Table

You’ll know your coffee beans have been scorched when there are dark marks on the green coffee bean that appear to have a burned consistency to them.

If you continue to make a cup of coffee with scorched coffee beans, you should expect your coffee to taste more burnt and smoky, which is not everyone’s cup of tea.


When some part of the roasting process slows down due to outside forces, not enough heat gets applied to the beans, which negatively impacts the overall flavor of the coffee. The opposite holds true if you roast the beans for longer than what is deemed necessary since the roasted coffee beans will develop undesired baking flavors as well.

Unfortunately, you cannot detect whether or not baking has occurred by observing the outside surface of the roasted coffee bean. In fact, you’ll have to compare the outside surface coffee bean color to the resulting color of the ground coffee bean to be able to identify if any baking has occurred.

Coffee Beans Baked

You'll know if a baking defect has emerged when the two colors appear to be identical to one another. Well-roasted coffee features an outside color that has a darker color to it than when you grind it, which is what you're trying to go for.

Baked coffee is often unwanted by a majority of avid coffee drinkers since it features a flat and bland taste that is often compared to oaty cereal.


After an in-depth look at typical coffee faults that can occur anytime from the harvesting to the roasting process, you can expertly determine whether or not the coffee bean you're buying is the optimal one for you.

Coffee aficionados always recommend buying whole coffee beans and grinding it yourself at home, so you have a point of reference to quickly detect any defects that the coffee beans may come with.

As you are well aware, any faults located in the coffee bean will translate to the overall taste and flavor of the coffee when you attempt to make a cup. Looking out for those faults is the only way to save yourself from ever having to drink a bad cup of coffee.