The more you pay attention to coffee flavors and tasting notes, the more you'll notice how specialty coffee processing shows up in your cup. It's a key step that makes a real difference in flavor, even between two beans from the same tree.
Do you imagine the bean reaches your cup exactly as it came off the tree? Not quite. A coffee bean has several components and layers that have to be dealt with first. Let's take a look.
What Is Inside a Coffee Cherry?
Picture a ripe red coffee cherry. Inside, there are usually two coffee beans, surrounded by several layers:
- Skin/Pulp: the outer layer of the cherry.
- Mucilage: a sticky, sugary layer beneath the skin.
- Parchment: a papery layer that protects the bean.
- Silverskin: a very thin membrane attached to the bean itself.
What Is Coffee Processing?
Coffee processing is the stage where coffee is handled after harvest to separate the beans from their outer layers and prepare them for drying and then roasting. It's a crucial step because it directly affects the coffee's flavor, clarity, sweetness and final body in the cup.
The main goal of processing: to remove the skin, pulp and parchment to reach the green coffee bean, while preserving its quality and developing its hidden flavors. How this is done is what makes the big difference.
Regular vs. Specialty Coffee Processing
Simply put, regular coffee processing usually focuses on drying and production in a conventional, relatively fast way, while specialty coffee processing is done with greater care and tighter control at every step to bring out the best possible flavor in the bean. (Read more about specialty vs. regular coffee.)
Specialty coffee processing methods fall into two groups: classic (traditional) methods and modern methods.
Classic processing methods:
- Washed
- Natural (dry)
- Honey
Modern processing methods:
- Anaerobic
- Aerobic
- Infused
Part 1: Classic Coffee Processing Methods
Three main methods formed the foundation of coffee processing for many years, and each leaves its own fingerprint on the coffee's flavor and tasting notes:
1. Washed Process
The washed process removes the outer layers of the coffee cherry before drying, using water or fermentation to help separate the sticky mucilage from the bean. It's one of the methods that shows a coffee's flavor most clearly, letting the bean express its origin in a cleaner, purer way.
How it's done:
After ripe cherries are harvested, the skin and pulp around the bean are removed using water or fermentation. The beans are then washed thoroughly to remove any sticky residue before drying begins. These careful steps help highlight the bean's natural characteristics.
Effect on flavor:
Washed coffees are clean and clear, often with bright acidity and precise, well-defined flavors. That's why this method is one of the best at showcasing a bean's original character, especially coffees with delicate floral or fruity notes.
Advantages:
- Clearly reveals the bean's original flavor.
- Gives the coffee a clean, bright character.
- Ideal for highlighting delicate floral and fruity notes.
Drawbacks and challenges:
- Uses more water than some other methods.
- Requires precise control of fermentation and washing.
- Any mistake can affect the clarity of the final flavor.
Ideal for: highlighting the delicate floral or fruity notes and distinctive acidity naturally present in certain varieties.
2. Natural (Dry) Process
The natural process is one of the oldest coffee processing methods. The whole coffee cherry is dried as it is, without removing the skin or mucilage first. This gives the bean more time to interact with the sugars and natural compounds inside the cherry, which clearly shows in the final flavor.
How it's done:
After harvest, whole ripe cherries are spread on raised beds or drying patios under the sun. During this time, they're turned and monitored constantly so they dry evenly, and the outer layers are removed once drying is complete.
Effect on flavor:
Natural coffees have more pronounced sweetness, a heavier body and bolder, deeper fruity flavors. Acidity is often lower than in washed coffees, while the overall character of the cup is fuller and more expressive.
Advantages:
- Gives the coffee prominent sweetness and strong fruity flavors.
- Creates a full body and a richer cup.
- Shows the bean's personality in a bold, distinctive way.
Drawbacks and challenges:
- Requires careful monitoring during drying to avoid spoilage or over-fermentation.
- Highly affected by weather, humidity and airflow.
- Any drying mistake can lead to unwanted flavors.
3. Honey Process
The honey process removes the skin of the coffee cherry while leaving part of the sticky mucilage on the bean during drying. It's named after this mucilage, which is sticky and sweet, much like honey.
How it's done:
After harvest, only the outer skin is removed, while some of the mucilage stays attached to the bean. The beans are then spread out to dry slowly under close monitoring, because the amount of mucilage left and the drying time directly affect the final flavor.
Effect on flavor:
Honey-processed coffees are balanced, combining flavor clarity with gentle sweetness and a fuller body. They're usually calmer than naturals but sweeter and smoother than washed coffees, which is why many people love them as a sweet spot between the two.
Advantages:
- Offers a great balance between clarity and sweetness.
- Gives a fuller body than washed coffees.
- Delivers a pleasant flavor profile loved by many specialty coffee fans.
Drawbacks and challenges:
- Requires precise drying control.
- Can be more sensitive to humidity and heat.
- Variations in the amount of mucilage can lead to inconsistent results if not monitored closely.
Variety: different levels (Yellow, Red and Black Honey) offer subtle variations in flavor and body.
Part 2: Modern Specialty Coffee Processing Methods
1. Anaerobic Process
Anaerobic processing is one of the modern, experimental methods in coffee processing. Coffee cherries or beans are fermented in sealed tanks that keep oxygen out. Controlling the environment this way creates a different reaction during fermentation, which clearly and distinctively shapes the final flavor.
How it's done:
After harvest, or in some cases after removing the outer skin, the coffee is placed in airtight containers or tanks so fermentation happens in an oxygen-free or nearly oxygen-free environment. During this stage, yeasts and bacteria interact with the beans differently, creating a flavor profile unlike traditional methods.
Effect on flavor:
Anaerobic processing gives coffee more complex, bolder flavors, often with unusual fruity notes, pronounced sweetness, or even wine-like or fermented notes. That's why it attracts coffee lovers looking for something new and different.
Advantages:
- Produces unique, unfamiliar flavors.
- Gives the coffee a clear, distinctive personality.
- Great for those who enjoy bold experiences and complex flavors.
Drawbacks and challenges:
- Requires very tight control over fermentation and temperature.
- Can produce unbalanced flavors if not executed precisely.
- Not for every palate, especially those who prefer clean, simple flavors.
2. Infused Process
Infusion is another modern, experimental processing method. The coffee is soaked in, or exposed during fermentation to, additional ingredients such as fruit or flavoring agents to give it a different aromatic or flavor character. It's one of the most intriguing methods in specialty coffee because it offers an unconventional experience, quite different from classic processing. Learn more in our guide: what is infused coffee?
How it's done:
The coffee is placed in a fermentation or soaking environment with added ingredients such as fruit, spices or other elements that influence the flavor. During this stage, the beans interact with their surroundings and pick up distinctive notes different from coffee's usual natural character.
Effect on flavor:
Infused coffees often have clear, unfamiliar flavors, with noticeable fruity, aromatic or sweet notes. This gives the cup a completely different personality, perfect for those who love experimenting and discovering flavors outside the ordinary. Explore the best infused coffee flavors.
Advantages:
- Gives the coffee an innovative, different character.
- Adds bold, clear flavors.
- Great for those who love new experiences and flavor surprises.
Drawbacks and challenges:
- Not a traditional method familiar to all coffee lovers.
- Can be controversial among some specialty coffee professionals.
- Requires careful execution so the added flavors don't overpower the bean's original character.
3. Aerobic Fermentation
Aerobic fermentation is a stage where coffee is processed in the presence of oxygen, either during fermentation or in parts of the drying stage. The term describes an environment where the beans naturally interact with air, making it closer to traditional, open-air processing methods.
Although "aerobic fermentation" comes up often when discussing coffee processing, it isn't really a standalone processing method; it's more a description of a stage that happens with oxygen present. It's mostly used to describe the fermentation or drying environment and to distinguish it from modern anaerobic processing.
How it's done:
The coffee is left to interact with air during fermentation or drying, without being sealed in closed tanks. This lets oxygen flow through the process, unlike anaerobic processing, which happens in a sealed, almost air-free environment.
Effect on flavor:
Aerobic fermentation usually produces coffee with clearer, more balanced taste and flavors closer to the classic, clean style. The flavors may not be as bold as anaerobic or infused coffees, but they give the coffee a natural character familiar to many coffee lovers.
Advantages:
- Closer to traditional processing methods.
- Helps achieve a balanced, clear flavor.
- Doesn't depend on complex fermentation or sealing.
Drawbacks and challenges:
- Doesn't always deliver the complex or unconventional flavors some people look for.
- Can feel less exciting than modern, experimental methods.
- Requires good control of time, temperature and humidity to protect bean quality.
Part 3: Experimental and Unconventional Processing Methods
In specialty coffee, innovation never stops. Producers and roasters are constantly searching for new ways to highlight flavors or create different experiences. Here are some experimental methods you may come across:
- Carbonic maceration: inspired by winemaking, whole coffee cherries are fermented in a carbon dioxide-rich environment, which can give the coffee bright fruity flavors and a distinct wine-like character.
- Lactic fermentation: encourages lactic acid-producing bacteria during fermentation, often resulting in a smoother body, more noticeable sweetness and more complex acidity.
- Co-fermentation (infused fermentation): external ingredients such as fruit or spices are added to the fermentation environment, directly affecting the flavor, though it remains controversial among some professionals.
- Innovative drying methods: such as precise control of temperature and humidity or special drying environments to improve quality and consistency.
With so many specialty coffee processing types and methods, you might wonder: what's the point of all this?
Processing methods may seem numerous and complex, but in the end they all aim to bring out the best a coffee bean can offer and create a more distinctive, clearer flavor experience. That's what makes every processing step an essential part of coffee's journey from farm to cup. To see how processing fits with other factors, read 7 factors that shape specialty coffee flavor.
Our Commitment at Microlot
At Microlot, we're always searching for coffees that represent the finest examples of careful processing. Whether it's the purity of a classic washed coffee, the bold sweetness of a natural, or the complexity of an innovative anaerobic, we aim to bring you coffees cared for at every step, so you can enjoy an unforgettable coffee experience.
Discover the Impact of Processing for Yourself
The best way to understand the difference is to taste it! Browse our diverse coffee collection and read the processing details and expected tasting notes for each one. Try a washed coffee side by side with a natural from the same region, or set off on an adventure with an anaerobic coffee. If you're comparing origins, our guide to Colombian vs. Ethiopian coffee is a great place to start.