Coffee Roast Defects: Identification and Prevention

Coffee roasters bring out their passion and skills to unleash the best flavor and aroma of the coffee beans during the coffee roasting process. However, even the most experienced professional coffee roasters may face challenges and make mistakes from time to time, resulting in less-than-perfect roasted beans. These imperfect roasts, called the coffee roast defects, can negatively impact the overall flavor and quality of the roasted coffee beans.

These defects can happen when roasters lack crucial information during certain key points of the roasting process. By having a deeper understanding about the types of coffee roast defects and their causes, we can identify and prevent them from happening.

 

Common Types of Coffee Roast Defects

Below are some common types of coffee roast defects and their causes:

• Baked coffee

Baked coffee is an invisible defect that happens when the beans are “stalled”, meaning they are heated for too long without reaching the first crack. Baked coffee is only recognisable during tasting, by its distinctive flat flavor with a hint of grain-like sweetness.

• Underdevelopment

Underdevelopment occurs when the roast is ended prematurely and the beans are removed before the sugars are fully developed inside the coffee beans. This resulted in roasted coffee beans with parts of them still raw, with “grassy” texture and hay or oat undertone of flavor.

• Overdevelopment

Overdevelopment is the opposite of underdevelopment, it happens when the roast happens for too long. The result is the loss of acidity and caramelization, leaving dark-colored beans with a burnt and bitter taste.

• Quakers

Although not technically a coffee roast defect, quakers can only be detected after the coffee roasting process is completed. Quakers are unripened beans that are typically the result of inadequate soil conditions and insufficient nutrition during cultivation, and appear indistinguishable from other green coffee beans.

• Scorching

Scorching happens when a small surface area of the roasted coffee bean is burnt, causing a bitter and smokey flavor to the cup.

• Tipping

Tipping is characterized by discoloration or breakage of the beans’ edges, which typically happens from roasting the beans too fast. The burnt and bitter taste is similar to scorched beans.

 

 

How to Identify Coffee Roast Defects

Coffee roasters strive to achieve consistency on their roasts and produce roasted coffee beans with excellent quality. Part of this job includes identifying and preventing coffee roast defects. There are various indicators that professional coffee roasters can use to identify defects in coffee beans:

• Visual indicators

Visual indicators can be an early sign of a coffee roast defect. Coffee roasters can examine the roasted coffee beans and identify the defects from the color of the beans. For example, underdeveloped coffee beans will have a light brown color, while overdeveloped coffee beans have a dark, shiny brown color. Scorching and tipping can also be identified visually, by the burnt marks on the edges of the beans for tipped coffee beans and on the surface of the beans for scorched beans.

• Aroma and flavor indicators

Oftentimes, coffee roast defects cannot be properly identified until the roasted beans are cupped. Coffee roasters need constant practice to hone their skills and instincts during cupping, to recognize the flavor, aroma, and mouthfeel of the coffee and identify the defects. Each coffee roast defect will have a different effect on the flavor of the coffee. For example, baked coffee beans taste bready, flat, or oaty, and quakers taste dry with papery and cereal notes.

• Special equipments

Roasters can use special equipment such as coffee roast analyzers and color readers to help measure consistency in roasting coffee. However, these equipments are quite costly. It is also advisable to record the Rate of Rise (RoR), which indicates the speed of the roast, to help coffee roasters understand what is happening to the beans during the coffee roasting process, prevent defects, and find the best flavor profile for their coffee beans.

 

How Can Berto Roaster Help Avoid Coffee Roast Defects?

Coffee roast defects can affect the flavor of the roast in different ways, from subtly obscuring flavor notes to drastically overpowering the overall flavor profile. Identifying and preventing coffee roast defects means you produce more consistent roasts and allow the unique characteristics of your coffee beans to shine through.

Below are some of Berto roaster machine’s features that can help coffee roasters avoid coffee roast defects:

• Drum size

Avoid overfilling the roaster drum to avoid scorching or tipping. Berto roaster machines have various drum capacities, from 1 kg to 60 kg, to suit your production needs.

• Agitation

Continuous bean movement is essential to prevent scorching and tipping. Berto Essential Air comes with an agitator inside the drum to ensure the beans are evenly moved throughout.

• Airflow control

Maintaining proper airflow during the roast is essential to avoid hot spots and to ensure the coffee beans roast evenly. With Berto roaster, the control is in your hand. Our roaster machines are designed to be highly responsive, airflow can easily be controlled using a damper.

• Monitoring and controlling

Bean and drum temperature are monitored through high-performance thermo controllers. Berto Roaster uses a state-of-the-art control system that guarantees the consistency of the roast.

• Data logging

Keep a detailed record of your roasting parameters and observation so you can easily analyze your roast and fine-tune your techniques. Berto roaster machines are compatible with Artisan or Cropster software for data logging and analyzing.

Ready to take the leap and make consistent roasts? Discover how Berto Roaster machines can help you avoid defects and achieve consistent, high-quality roasts.