Why are coffee beans roasted? Read this first! (2023)

Why are coffee beans roasted before brewing? Read on to find out why and how they are roasted to give you the perfect flavor.

Why are coffee beans roasted? Read this first! (1)

From being harvested as coffee cherries in the country of origin to being processed and shipped worldwide for roasting, coffee beans go through a lot before they get into your cup. I'm amazed at people who think coffee beans are picked straight from the trees! If you love your cup of joe, you should at least know about your bean's fateful journey!

Why are coffee beans roasted at all?

Unroasted beans have no aroma or taste. They are seeds contained in coffee cherries. Although raw green beans contain all of the complex compositions and chemicals, they only give off irresistible coffee aromas and flavors when roasted at high heat.

When raw coffee beans are exposed to varying degrees of heat in a roaster, the complex structure breaks down, releasing carbohydrates, minerals, amino acids, water, proteins, lipids and caffeine. The roasting process givesCoffee beans the flavors of candy, chocolates, flowers and fruits.

Green beans are hard, tasteless, and insoluble. The intense heat during the roasting process breaks down the outer structure of the cellulose and makes the outer shell porous. This allows the water better access to the coffee solubles as they dissolve. This is called extraction during the brewing process.

Unfortunately, roasted coffee beans are prone to aging and begin to lose flavor soon after roasting and exposure to air. Therefore, you should always buy freshly roasted beans and store them in an airtight container away from air, moisture and direct sunlight.

Table of contents

  1. How are coffee beans roasted?
  2. What are the different coffee roast profiles?
    • light roasts
    • medium roast
    • medium roast
    • dark roast
  3. This is how you can tell if your beans are freshly roasted
    • 1. Check if you have oily or shiny skin
    • 2. Keep an eye on waste
    • 3. Put some beans in a resealable plastic bag and see what happens.
    • 4. Check the coffee bag for gas.
  4. Why coffee beans are roasted: the final words

How are coffee beans roasted?

If you get a chance to visit the inside of a coffee roastery, you can see green beans piled up in large sacks transforming into aromatic beans. Here's a breakdown of the steps that bring about this beautiful change.


The raw green beans are first deposited into giant hoppers, which are the roaster's loading system. When the indoor air temperature hits the 500F mark, the beans are dumped into a rotating hot drum to begin the roasting process.

Inside the drum, countless paddles fling the granules into the air to promote even heating throughout the process. It works similar to a home clothes dryer.


The green beans are subjected to high heat for the first five minutes to bring them to the perfect roasting temperature. This step is done carefully to ensure there is enough moisture in the beans without burning the outer skin.

At this stage, the color of the beans changes from green to light yellow and the aroma also changes from a fresh grass smell to something similar to hay.


Over the next 5 minutes, the beans are slowly roasted at roasting temperatures that typically range from 300°F to 350°F. This step develops the precursors for the aromas and flavors that will follow later when the roasting temperature reaches high levels.

During this step, the internal pressure, temperature and humidity must be carefully and carefully regulated. At this stage, the beans change from yellow to light brown and the aroma changes from hay to freshly baked bread.


The full aroma of the coffee beans unfolds in the last 2 to 5 minutes. the fFirstCracking, commonly known as popping, occurs at around 360°F when grains expand under the pressure of water vapor and carbon dioxide created as a result of chemical reactions.

The internal pressure drops drastically and the gases that form inside the grains can escape. This creates the ideal internal pressure, temperature and humidity for optimal flavor development.


When the temperature reaches the range of 360°F to 395°F, the amino acids and sugars contained in the coffee beans react quickly. Helps develop the coffee's final, fuller flavors. The caramelization of the natural sugars during the Maillard reaction gives the medium roast a distinctive flavor.

When the temperature reaches the range of 360°F to 395°F, the amino acids and sugars contained in the coffee beans react quickly. Helps develop the coffee's final, fuller flavors. The caramelization of the natural sugars during the Maillard reaction gives the medium roast a distinctive flavor.

At this stage, the coffee beans will darken slightly and develop a malty character and nutty flavor, similar to cocoa. It looks easy on the eyes and almost resembles the coffee beans you see in stores.


Different types of coffee beans are treated with different temperatures and roasting times. These complexities are decided by the roasting team. For example, Honduran espresso beans are roasted at a temperature of 389°F while Yirgacheffe coffee beans are roasted at a temperature of 380°F.


When beans are roasted above 395Marke, their hue continues to darken and they are known as dark roasts. At the extreme temperature, the flavors and aromas developed in the initial phase are completely reformulated and the beans develop new smoke, spice and roasted aromas.

The sour and sweet taste is replaced by a touch of bitterness. Most pure dark roasts are heat treated between 410°F and 420°F to develop fuller, deeper characteristics.

What are the different coffee roast profiles?

light roasts

Light roasts are often referred to in the coffee world as Half City, Light City, Cinnamon Roast or New England Roast. They are light brown in appearance with no oil on the outer surface. They are lightly roasted for a grainy flavor and are naturally acidic.

The original aromas are preserved with a light roast and show a higher caffeine content in the coffee bean. Light roasts occur when the temperature inside the roaster reaches 356 – 401°F. At around 401°F, the bean will pop or pop, indicating the first crunch.

Light roast means the coffee beans were not roasted after the first burst. This type of roast is popular in the Northeastern United States.

medium roast

Why are coffee beans roasted? Read this first! (2)

Medium roasts are often referred to as American Roast, Regular Roast, City Roast or Breakfast Roast. They appear medium brown and have a fuller body than light-colored roasts. As a light roast, they also don't have a greasy surface, but aren't grainy.

Medium roasts occur when the roaster reaches an internal temperature of 410 to 428. The phase begins with the first crack and ends just before the second crack.

They have a more balanced taste, aroma and acidity. This profile has a reduced caffeine content and again culminates in darker roasts.

medium roast

Medium dark roasts are also known as full-city roasts, Vienna roasts, and after-dinner roasts. They look richer and darker with the outer surface feeling greasy. These beans have a fuller, heavier body compared to lighter or medium roasted versions.

Medium dark beans develop when the roaster reaches a temperature between 437 and 446°F. They are roasted at the beginning of the second snap and some variations are roasted in the middle of the second snap. Aromas and flavors are more pronounced and the taste of medium roast beer can be slightly spicy.

dark roast

Dark roasts are often referred to as Italian roasts, French roasts, continental roasts, express roasts, New Orleans roasts, and Spanish roasts. They are dark brown in color, almost black. A thin film of oil can be seen on the surface, giving them a shiny appearance.

Dark roasts are achieved when the internal temperature of the roaster reaches 464°F or higher. The original aromas of the dark roasts are overlaid by the aromas released during roasting. If you use a dark roast to brew, your coffee will taste smoky, bitter, or even acidic.

These distinct flavors develop as the second crack runs out or beyond. They are rarely roasted above 482°F, which often gives the beans a charred and tarry flavor.

This is how you can tell if your beans are freshly roasted

When buying coffee bags or loose coffee beans in the store, one can often wonder if they were recently roasted or have been on the shelf for days. Although roasted beans can keep for about a month, they shouldbe guarded with careto avoid the loss of characteristic flavors and aromas.

My friends always ask me how I can tell if beans are freshly roasted, as they are amazed at my judgment skills! I've noticed that many people have the same problem, so I decided to share some tips to help you find out how fresh your roasted beans are.

1. Check if you have oily or shiny skin

Coffee grounds contain acids, oils, and other essential compounds that add an intriguing aroma and delicious flavor to your morning cup of coffee. Often referred to as coffee solubles, these chemical compounds are released during the extraction process.

When green beans are treated at high temperatures, the moisture inside evaporates and the heat extracts an oil-like substance that coats the outer surface. This is not real oil and will evaporate quickly if the beans are exposed to air.

If the beans sit for a long time after roasting, the surface will not become greasy. Note, however, that not all types of beans give off the same amount of oil; Therefore, be careful when using the oil as an indicator of freshness. Also, lighter roasts don't have a very shiny surface.

2. Keep an eye on waste

If the beans are roasted withSwiss water process(caffeine is extracted with water rather than chemicals), you'll end up with duller roasts by comparison. Pick up some beans and you will see that they leave residue. You might even notice a residue in the bag of beans you bought at the store.

The residue indicates that the beans are freshly roasted and therefore oily. Lighter roasts may not be as oily as darker ones, so don't expect too much residue in this case.

3. Put some beans in a resealable plastic bag and see what happens.

Why are coffee beans roasted? Read this first! (3)

Many people prefer to buy beans in bulk rather than grab vacuum-sealed bags off the shelves. So if you bought in bulk but some grains in a plastic bag, squeeze all the air out of the bag and seal it. Let the bag sit like this overnight.

Examine the plastic bag the next morning to see if there is a difference. If the beans have recently been roasted within a week or even the past ten days, the plastic bag will inflate like a balloon due to the carbon dioxide they release.

4. Check the coffee bag for gas.

Coffee beans release a large amount of gas (mainly carbon dioxide) after being roasted at high heat and then cooled. The gas continues to be released for a few days to many weeks after roasting, and this period is often referred to as degassing or degassing.

During the first days of roasting, the beans are released quickly and the intensity gradually decreases. When fresh roasted degassed beans are packed in vacuum bags, they need an outlet, otherwise the bag will burst like a balloon.

So manufacturers build one-way valves into airtight bags to allow gas to escape without air getting in. If the vacuum bag has an air valve, this indicates your beans have been freshly roasted.

Why coffee beans are roasted: the final words

Sometimes I feel like roasting the beans is like true friendship. Nothing is as neutral to begin with as raw green beans. As they become known, the flavors slowly begin to cook like pale roasts, and once a lifetime bond is formed, they unleash the deepest flavors and strongest flavors.

Depending on which type of coffee you prefer, you can choose between light, medium or dark roasted beans. The next time you buy whole beans, look for signs that indicate whether or not they have been freshly roasted.

The week-long roasted beans have a distinctive smell that will overwhelm your sensesmoê-los, and your morning joe will taste divine! If you're new to making coffee, you'll soon be able to tell fresh beans from old just by looking at them.

  • Why are coffee beans roasted? Read this first! (4)

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