Coffee Bean Production Process and Common Coffee Processing Methods

Coffee Bean Processing Methods

Coffee bean processing mainly refers to two types:

1. The first type refers to the processing method from coffee cherry to green coffee bean, which is what we commonly call washed processing, natural processing, etc.

2. The second type refers to the processing method from green coffee bean to roasted bean;

Coffee Processing Methods

The process of transforming coffee cherries into coffee beans is called coffee processing. There are increasingly many coffee bean processing methods, but the beans at FrontStreet Coffee basically cover all current mainstream processing methods. The store also displays and showcases beans with different processing methods for customers' reference. Today, let FrontStreet Coffee start by introducing the four most basic coffee bean processing methods: natural, washed, semi-washed, and honey processing.

Coffee Cherry Structure

The structure of coffee cherries, which resemble cherries, consists of the following layers from outside to inside: skin, pulp, mucilage layer, parchment layer (seed coat), silver skin, and seed. The mucilage layer is about 1-2mm thick and can be imagined as the translucent substance around tomato seeds, making it difficult to remove. The green beans we generally buy are actually the innermost seeds, perhaps still containing some residual silver skin.

Processing Methods Overview

Various processing methods share the same goal: removing the skin to obtain the beans. Based on economic cost considerations and differences in natural environmental conditions like climate, the bean extraction process may not be identical. However, the process does affect the result!

Natural Processing Method

Advantages of Natural Processing

1. Simple, with low processing costs.

2. Green beans naturally dry within the fruit pulp, absorbing the fruit's essence, resulting in rich fruit aroma, noticeable sweetness, and excellent body.

Disadvantages of Natural Processing

1. In some producing regions, natural processing doesn't screen out floaters, causing quality inconsistencies.

2. During the drying process, the pulp can easily become moldy due to climate-related moisture reabsorption, contaminating the green beans.

3. Machine hulling inevitably damages some green beans, causing appearance defects.

Natural Processing Steps:

Natural processing is the oldest and most hassle-free green bean processing method.

Step 1: Screening Floaters
Place harvested coffee cherries into large water tanks. Mature, full cherries will sink to the bottom, while underdeveloped or overripe cherries will float to the surface. These floaters must be removed.

Step 2: Natural Sun Drying
Next, place entire coffee cherries with skin, pulp, and parchment intact onto drying patios for natural sun drying until the moisture content reaches about 12%. This takes about two to four weeks, depending on the origin's climate.

Step 3: Hulling
Use hulling machines to remove the dried hard skin, pulp, and parchment layer from the naturally dried fruit, revealing the green beans.

Washed Processing Method

Washed processing is currently the more common green bean processing method.

Step 1: Screening Floaters (same as natural processing)

Step 2: Pulp Removal
Send fresh cherries through a pulping machine to remove the skin and pulp. Immature cherries, whose pulp doesn't separate easily, will be screened out at this stage. After passing through the pulping machine, what remains are mucilage, parchment, and seeds.

Step 3: Fermentation to Remove Mucilage
Move the depulped seeds with mucilage into fermentation tanks. Although it's called the "washed" method, it doesn't actually wash away the mucilage. Instead, fermentation uses biological decomposition to remove the mucilage. The fermentation process takes about 16-36 hours, during which the beans must be stirred frequently to accelerate mucilage separation from the seeds. Washed fermentation produces acidic substances like citric acid, malic acid, and acetic acid. These acid values penetrate the green beans, making washed processed beans more acidic than naturally processed ones. After fermentation is complete, the actual washing begins—washing the beans again.

Step 4: Drying
After washing, the beans still need to be sun-dried or machine-dried to reduce moisture content to 12%. Since washed processing has already removed the pulp, there's no need to worry about mold issues during drying like with natural processing. The dried parchment coffee beans are not as hard as those containing pulp and skin in natural processing, so they can be hulled using a hulling machine to obtain green beans.

Coffee Roasting Process

Roasting Process Description:

1. Bean Selection Before Roasting: Although beans have been selected multiple times at the coffee origin, FrontStreet Coffee needs to select beans again both before and after roasting.

2. Roasting: Use a roasting machine to roast according to the bean's roasting profile at 190-202°C for 9-15 minutes.

3. Post-Roasting Bean Selection: Select beans again after roasting.

4. Packaging: Wait for the coffee beans to cool completely, then package and ship them by category.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473