What is roasting coffee? And how do you do it?

Coffee roasting

Roasting coffee is the process in which heat changes the small green coffee beans into the beautiful brown colored and deliciously scented coffee bean that we all love so much. To wake up nicely or to end a meal appropriately.

There are also different brandings such as; light, medium and dark, but is it really as simple as heat and time? In this blog we tell you how roasting coffee works and how we do it.

What is coffee roasting

Coffee roasting is the process of converting green coffee beans into the fragrant, brown beans we know and enjoy every day. During roasting, the coffee beans are exposed to high temperatures, where the moisture in the beans evaporates and the beans swell.

The roasting process is an art mastered by the roasters, who carefully monitor the temperature, airflow and duration of the roasting process.

Depending on the desired roast level, the coffee beans can develop different flavors and aromas, such as fruity, floral, chocolatey or smoky notes. It is important to carefully roast the beans to achieve the desired flavors and aromas while not burning or ruining them.

Coffee roasting is an important part of the process of making a great cup of coffee. It affects not only the taste of the coffee, but also the aromas and body of the coffee.

Why do we roast coffee?

The coffee bean that is so sacred to us is unroasted (green) almost odorless and tasteless. To extract the aromas from this bean, it must be exposed to a high temperature for a set period of time.

The unroasted coffee bean can be stored for up to two years. Once the coffee is roasted, the beans smell like coffee, look like coffee and taste like coffee. From this moment on, the coffee shouldbe drunk within a period of 6-8 weeks for an optimal taste experience.

Coffee berries Unroasted coffee beans still in the husk credit: The Coffee Quest

What happens when roasting coffee?

Before the green, raw coffee beans turn into brown, drinkable coffee beans, the coffee beans go through different stages. These are described in detail below.

The different phases of coffee roasting

  1. The drying phase: a crucial phase, coffee roaster of Zwarte Roes, Marvin Antonius. “This is the phase that determines the overall batch time as it is driven by the initial moisture content of the beans. It basically lays the foundation for all the other phases as it determines how quickly your coffee beans are sent to the first crack.”

  2. Maillard reaction: The first color change of the coffee. This reaction is the catalyst for the formation of many of the 1,000 volatile chemical compounds (that is, compounds that readily evaporate into the air and therefore contribute to coffee's aroma) created during the coffee roasting process. This process is most closely associated with the smell of freshly baked bread.

  3. First Crack: While the first stage of the roasting process mainly deals with the heat that is penetrated into the coffee beans by the flame, the second stage has to do with the energy that has built up in the coffee bean. The heat that has built up in the bean wants to get out and causes the coffee beans to crack. This is exactly like the sound of popcorn popping when it turns into corn popcorn.

  4. Second Crack: Some coffees are roasted very dark and then continue to the second or second crack.

  5. Complete burn: At this point the coffee beans are completely burnt. As a coffee roaster you have to watch out for a fire hazard at this point

Roasting coffee as art

Coffee Flavor Wheel

In practice, it is not just a matter of adding heat to the raw coffee to make it into coffee. It is both an art and a science to be able to roast good coffee. A few seconds or a few degrees difference can turn a great batch of coffee into a failure.

In addition, consistency is very important to be able to deliver the same quality time and time again. A helping hand is a roasting profile software to measure progress batch after batch.

fire profile black Roes

Coffee roasting as a science; roasting profile graphs Zwarte Roes Specialty Coffee

What are the different brands

Coffee roasters can choose their own roasting profiles, but this depends on the type of coffee, the quality and the intended brewing method. However, there are no standard roast profiles, which sometimes makes it a bit unclear. But roughly speaking, there are light roasts, medium roasts and dark roasts.

Light roast

We use this light roast for coffees that are potentially very fruity or floral. These taste notes are better brought out by the light roasting and sometimes gives an almost tea-like experience. At Zwarte Roes we advise to serve these coffees by means of slow coffee .

In addition to our standard range, we always have a selection of specials that we roast in this way.

Medium roast

Medium roast coffees are roasted slightly darker to a slightly darker brown color. The body in this type of toast is fuller and rounder, but the character of the berry is still preserved. We try our coffees, suitable for espresso or, for example, burn the fully automatic machine in this spectrum. This way you get a strong coffee with sweet tones of the coffee cherry, without the coffee becoming bitter.

Dark roast

Very dark roast coffee is almost black in color and has an oily sheen on the outside of the bean. Coffee that is roasted this dark has a lot of dark and bitter tones and can have a very full body. However, this type of roast leaves little of the original characters of the coffee.

We do not roast dark coffees because we think this is a waste of the high quality of the coffee and the special flavors.

Drink freshly roasted coffee

After roasting the coffee, we naturally prefer to drink the coffee. But you still have to be patient! When the coffee has just been roasted, the beans are still full of CO2 and need time to 'degas' before the coffee has reached its optimal flavor potential. This period is usually at least 24 hours.

After this period, the coffee reaches its peak, which decreases over time. The period in which freshly roasted coffee can best be drunk is 24 hours after roasting up to and including6-8 weeks after branding. We therefore always recommend buying coffee in quantities that you can drink. So never buy more coffee than you will drink in, for example, 6 weeks.

Related: Which Coffee Beans Should I Choose? ,New to the coffee world? 5 hints.