Green Unroasted Coffee Beans

Green coffee beans come in two main species: Arabica (Coffea arabica) and Robusta (Coffea canephora). Each species has distinct growing conditions, flavour profiles, and caffeine content. Here’s a closer look:

Arabica Coffee Varieties
Arabica, known for its complex flavours and balanced acidity, makes up 60-70% of global coffee production. It is typically grown at high altitudes (1,200-2,200m), which enhances its unique flavour profiles. Popular Arabica varieties include:

• Typica: Known for a clean, sweet taste with notes of fruit, florals, and chocolate.
• Bourbon: Prized for its sweet, full-bodied flavour with notes of caramel, nuts, and red fruit.
• SL28 and SL34: Originating from Kenya, these beans offer bright acidity and fruity notes, such as blackcurrant.
• Gesha (Geisha): Renowned for its floral aroma, tea-like body, and hints of bergamot and tropical fruit.
• Caturra, Catuai, and Pacamara: Hybrid varieties developed for resilience while maintaining Arabica’s complex flavours.

Robusta Coffee Varieties
Robusta has a stronger, more bitter flavour with earthy, woody notes and higher caffeine content (2.2-2.7%). It’s typically grown at lower altitudes (200-800m) and is known for:

• Higher Caffeine Content: Contributes to a bold, bitter taste, often used in espresso blends.
• Flavour Profile: Strong, earthy flavours with a thicker crema, making it popular in espresso and instant coffee.

Other Notable Varieties:

• Liberica: With fruity, floral, or smoky notes, Liberica beans have a unique, bold profile and are primarily grown in Southeast Asia.
• Excelsa: A variant of Liberica, known for its tart and fruity notes, adding depth to coffee blends.

Basic home roasting equipment includes a stovetop popcorn popper, baking sheet with an oven, or a dedicated home coffee roaster. You’ll also need a kitchen scale, thermometer, and a fan or colander to cool your freshly roasted green coffee beans.

The first crack is an audible popping sound, signalling that the beans are reaching a light to medium roast. The second crack is softer, indicating a medium-dark to dark roast. Listening for these cracks helps determine your roast level.

To cool beans quickly, spread them on a metal colander or tray and use a fan to blow air over them. This stops the roasting process, preserving the desired flavour profile in your unroasted coffee beans.

Roast development time is the period after the first crack until the roast is complete. This time impacts flavour: a shorter development time can create a sour taste, while longer times may result in a bitter or smoky flavour.

Higher-density beans (often from high altitudes) require more heat to develop flavours, while lower-density beans need a gentler roast. Adjust heat and airflow accordingly for even roasting based on bean density.

Airflow controls temperature and removes chaff (the bean’s outer skin). Proper airflow prevents smoky flavours and allows for better control over the roasting process.

Yes, green coffee beans can absorb odours from their environment. Store them in airtight containers, away from strong-smelling items, to preserve their natural flavours.

Scorching is typically caused by high initial temperatures, especially when the beans first enter the roaster (known as "charging"), combined with inadequate agitation. If the drum or roasting environment is too hot, or if beans sit too long in one spot, they can burn on the surface before the inside is properly roasted.

A smoky or ashy flavour often results from not enough airflow during roasting or failing to remove chaff properly. Make sure to ventilate your roasting area and stir beans well to avoid these flavours.

Use the same batch size, set a consistent preheat temperature, and keep detailed notes on time, temperature, and airflow. Also, make sure to agitate the beans evenly to prevent scorching or under-roasting.

Beans can chip or break due to extreme temperature changes, over-agitation, or using old, low-quality beans. Ensure a gradual temperature increase and consistent agitation to prevent this issue.

Clean your roaster regularly by removing chaff, wiping down surfaces, and using a vacuum or brush to clear out any remaining debris. This prevents the build-up of oils and burnt material, which can impact future roasts.

Stale green coffee beans may appear faded or dull and may have a musty smell. They also lose their characteristic "crunch." Roasting stale beans results in flat, lacklustre flavours.

Green coffee beans should be stored in a cool, dark place, ideally in an airtight container, to preserve their freshness and flavour. Avoid direct sunlight, humidity, and exposure to strong odours, as they can absorb smells from their environment.

Unroasted coffee beans, when stored properly, can maintain their quality for up to a year or more. However, for the best flavour, it’s recommended to use green coffee beans within 6-12 months of purchase.

Lighter roasts tend to retain more caffeine than darker roasts. However, the difference is minimal. The biggest impact on caffeine content in your coffee is the type of green coffee bean (Arabica vs. Robusta) rather than the roast level.

Yes, blending green coffee beans before roasting allows you to create custom flavours. However, since different beans may roast at different rates, you might need to experiment to find the best balance for each blend.

Consistency in roasting comes with practice. Track your roasting times, temperatures, and airflow settings. Roasting similar batch sizes and using consistent equipment also helps in achieving uniform results.