How to Roast Coffee Beans Professionally? The raw coffee beans are loaded into a loader and then fed into a rotating drum. The drum is preheated to a temperature of about 240 degrees.
After 12-15 minutes depending on the roast type, the roasted beans will come out of the drum at a temperature of about 195 degrees and are then taken out to the cooling tray at the front of the roaster.
How to Roast Coffee Beans Professionally
How to Roast Coffee Beans Professionally? They are then passed through a machine that removes rock or debris before being inspected by hand for any defects, and after being completely cooled, finally packaged for sale.
Watching Roasted Coffee
Nisbets recently did a Coffee Extract tour in Bristol to see in detail How to Roast Coffee Beans Professionally from sack to bean. We spoke coffee with David Faulkner, Director & Chief Roaster with an interview, along with more insights and tips from roasters Mac and Ashlee.
First, the coffee beans are fed into a drum inside the roaster, which rotates over the gas burner and stirs the coffee.
This particular roast will be espresso coffee, from a single brewery in Peru and will take about 12-15 minutes using 3 kilos of raw green beans.
It is a washing process which means that when the coffee cherries are picked, all the pulp and skin of the fruit are removed before the drying process.
This makes for a really clean and balanced coffee with lots of sweetness. In the early stages, roasts can smell like hay. Naturally, your senses need to be tuned into the roast, with all other aromas wafting throughout the roast. This is how you really learn to roast coffee, without the help of software and sensors.
An espresso roast takes a little longer to extract more of the sweetness and body, which is more resistant to the intensity of the espresso brewing.
How to Roast Coffee Beans Professionally? So coffee beans roast a little more than filter coffee, for example. This encourages the development of sugar further so you can achieve that extra sweetness.
One of the by-products resulting from roasting is called ‘husk’. This is the final layer that surrounds the coffee cherry beans, when the beans get hot they shed this coat like a nutshell.
It is collected and recycled in compost, as it contains a lot of nitrogen and can also deter pests due to its caffeine content. Coffee cherry skins are also starting to be used more often to make tea, known as ‘cascara’ (pictured right).
Coffee beans begin to expand as they become hot, achieving a mottled yellowing effect. Coffee beans take in more energy as heat as they roast, when they reach a point when they can no longer take in any more energy the reaction becomes exothermic.
This is an important time as the coffee begins to develop all the sugar and oil needed to produce a full espresso flavor.
This is also an important time when it comes to adjusting to the heat being brought into the roast. The coffee is browned because the natural sugars are caramelized, which begins to produce a pleasant malt smell. Although this roast smells good, the seeds are quite far from the finished product.
As the coffee beans expand further with heat and pressure, they begin to generate their own heat and make an audible ‘cracking’ sound. This stage is known as the ‘first crack’.
None of the coffees at Extract ever made it to the second crack. This is usually the time to reduce the gas, to compensate for the heat given off by the beans. However, since this is an espresso roast, the heat is back up again.
How to Roast Coffee Beans Professionally? Coffee beans are monitored very closely, and when roasted to an optimal color and level of development, they must be stopped roasting further through a refrigeration process.
The coffee beans are then released into the cooling tray under the front door of the roaster, which rotates to distribute evenly. Air is drawn through the tiny holes to cool the coffee beans evenly.
How to Roast Coffee Beans Professionally? Espresso roasts like these tend to last a little longer than filter coffee roasts, but they can also be too fresh. When the coffee is very fresh, there is still a lot of gas in the coffee beans which can be very volatile during the extraction process, making it quite lively and sour in taste.
In this case, leave the coffee for 7-10 days after the roast date as is always recommended before brewing. The coffee can last for a month, or even two, depending on whether it is stored properly.
Tip: Store ground coffee in an airtight (ideally opaque) container and store in a cool, dry place. Storing the pulp in the refrigerator is not a good idea as it will create odors and other contaminants.
How to Roast Coffee Beans Professionally? As the coffee cools, any defects can be picked up from the batch. Some are known as Quakers, which only appear after the coffee is roasted.
These are low-sugar nuts, so they may not be fully ripe and therefore not turn a dark brown color because they don’t have enough sugar to caramelize.
They looked undercooked but actually tasted like they were charred. They are not a sign of inferior coffee and are quite common. Pea berries can also be found in every batch of roasted coffee. With the average coffee cherry, there are two beans facing each other.
Around the seeds, there are mucilage, fruit flesh, and skin. With peaberries, also known as pearls, they will stand alone as a single seed within the cherry creating an almost perfectly round shape of the fruit.
This is considered a natural defect and will be present in every batch of coffee. Peaberries are sold alone and tend to be very sweet, making them perfect for espresso coffee.
Elephant ears are so named because of their shape. This can occur during seed formation when some of the seed detaches and makes it less dense. It is simply discarded from the batch. Small or cracked nuts can be a sign of poor judgment.
Coffee Beans at Every Stage Of The Roasting Process
Raw, unroasted green beans can be seen at the top left of the image. This is how they look fresh from the sack.
The top row of beans shows the phase between the initial drop, to a point after about four minutes of roasting time. There isn’t much sugar development during this period, as nuts only start to do so after about six minutes.
How to Roast Coffee Beans Professionally? The last three examples shown at the bottom right are over-roasting, to show how far roasting can go. At this stage, the sugar stops growing and the nuts start to burn. They will turn a glossy color as the oil is forced out, and the nuts will become dehydrated.
These beans are what you might expect to see in most commercial coffee shops to fill a western palette, tasting ash and charred. In the western world, most coffees are roasted to this degree which creates a bitter taste, which is why milk and sugar are often added.
1. Experimental Bake
How to Roast Coffee Beans Professionally? The extract has a small roaster called ‘The Professor’, which is designed for small-batch roasting. These smaller batches serve as tests for new coffees, which are then scaled up for larger roasters.
Since coffee samples are shipped from a variety of importers, it makes sense to try a small batch of 100g roast in a test roaster. This roaster doesn’t have software, so this is how you learn to roast and select coffee.
The Professor is made from a recycled popcorn machine, along with some parts from an old grinder. On the side of the machine, note notes about roasting, such as not roasting evenly or not sounding cracks.
Maybe the nuts are slanted, which means they cracked a bit from the heat. This gives an indication of what is to come on a larger scale.
2. Baking White Label
It may sound like cutting a vinyl plate, but Extract actually roasts what is known as ‘white label’ coffee as a way to test new and exciting blends.
“We do this for places like the Boston Tea Party and River Cottage. We bake it for them, then they visit us afterward and give us feedback on the mix and its characteristics.” Mac – Coffee Extract.
How Do Bigger Grills Work?
How to Roast Coffee Beans Professionally? First, the coffee beans are loaded into the loader, then to the backing line which carries it to the drum. The burner underneath heats the drum, until it reaches the right temperature.
Next, the beans are released into the roaster, a typical roast taking about 15 minutes. Coffee beans are dropped at about 240 degrees, but this varies from coffee to coffee.
Espresso roasts require a longer roast to extract more sugar from the coffee beans, filter coffees require a little less heat, and shorter, lighter roasts to pick out a more fruity aroma from the coffee.
When the coffee beans finish in the large roaster, they go into what’s called a ‘de-stoner’, which is basically a vacuum line. It takes the coffee into the hopper and if it is heavier than the coffee it falls off and is ejected.
“We found Betty, our 60kg Probat grill from 1955, covered in soot in an old shop in Wales and almost the size of the shop itself!” Mac – Coffee Extract.
Coffee Roast Business
1. Using Vintage Machines
One of the first things to notice at Extract Coffee is the visual capture engine that almost resembles part of an old steam engine.
How to Roast Coffee Beans Professionally? Each machine has been lovingly restored, often based on technology from decades past which begs the question: ‘what are the benefits of using a vintage machine over a modern commercial roaster?’
“They have an aesthetic that newer machines don’t have. They’re also easier to use. We also buy them when they need a bit of ‘TLC’, then spend a lot of time restoring them.
It’s cheaper, and we also find out how it works by taking it apart. Once we’ve done this, we can modernize it, install a new burner and control system, and digitize the probes so we can see what’s going on inside.
In the case of this engine (Bertha), we have added an afterburner at the rear. All the smoke coming out of the engine goes into the afterburner, which removes all the smoke so we just blow out clean air. This ensures that we don’t disturb our neighbors!” David – Extract Coffee.
2. The Right Source of Coffee
How to Roast Coffee Beans Professionally? It is clear that the entire food sector has changed in the country, with regard to purchasing local and seasonal produce, and the same is true for coffee.
There is still some ambiguity over terms like ‘fair trade’ and ‘ethics’, which seem to vary according to who you ask in the coffee industry, whether it’s a barista, coffee shop owner, or buyer.
David insists that a great cup of coffee comes from a farm with good, technical, and well-paid farms.
“It’s about relationships, which we’ve been working on for a long time. We have a farm that we’ve been using for six years, where we started buying two bags of coffee, now we’re buying three containers. for sustainability, and fair trade.” David – Coffee Extract.
Consumerism is now at a point where knowledge is part of the value. How to Roast Coffee Beans Professionally This has become very important, where customers want coffee from a certain country, they are now much more specific about their requests, wanting Kenyan varieties and the washing process for example.
Therefore, the days of mixed secrets seem like a thing of the past, with knowledge and backstories an integral part of the product.
“You sell a great chef’s knife and the quality speaks for itself. In the same way in coffee plantations, with Instagram, Twitter, and other social media platforms, there is no filtering of information because farmers own those things, even in Peru more than 2000 meters above sea level!
So no more ‘dark ages’. How to Roast Coffee Beans Professionally? Isn’t a magic machine either, you can’t add anything to the coffee but make it tastier. So as a roaster, the source of the coffee is the first hurdle, and the most important.” David – Coffee Extract.
Article: For more information on the history of coffee, read our article on the Coffee Wave.
Bean To Cup: Barista Tasks
In Italy, the role of a barista has always been one that is respected as a good skill. In the UK, this job still seems to be greatly underestimated by both cafe owners and customers, but times are changing.
“One of the things we underestimated when we first started the coffee roasting business was training and education. We initially thought it was about selling and buying coffee, and anyone could make it, but we had to learn this first.
Ourselves, and now we teach skills. We teach people to get accredited, so we have in-house trainer Dan who does a fantastic job.” David – Coffee Extract.
1. See the Roastery for yourself
How to Roast Coffee Beans Professionally Extract encourages all consumers, restaurant, hotel, and cafe owners to get to know their local roastery to find out more about the coffee on offer.
They provide free training to all their accounts because they want to make sure their coffee always tastes the way it should. Just go to Extract Coffee where they bake to order.
Inside the roaster, you’ll find a selection of freshly ground coffees and beans, along with a friendly, passionate, and enthusiastic team.
It is well worth a visit whether you are a coffee lover, barista, or cafe owner as getting to know your local roastery will only benefit the coffee chain.
The folks at Extract also point out that specialty coffee capsules look set to make a big impact on the coffee market soon.
Coffee roasting process
How to Roast Coffee Beans Professionally from green to brown. There are different ways to make it, and that affects the taste. Here I will discuss the principles of commercial roasting and roasting.
1. Baking stage
There are three main stages in roasting: the drying stage, the browning stage, and the development stage or roasting stage.
2. Drying Stage
Coffee beans have 8-12% moisture. We need to dry it before the actual baking begins. How to Roast Coffee Beans Professionally? The drying stage typically lasts 4-8 minutes with a traditional drum roaster (see below for roaster designs). The temperature at the end of the drying stage is usually 160°C.
Especially with a drum roaster, you have to be careful not to burn the beans from getting too hot in the first place. The drying stage is also important for gathering energy for the beans because the last stage of roasting is exothermic (generating heat).
3. Browning Stage
How to Roast Coffee Beans Professionally? From 160 C the coffee starts to smell like toast and hay. This is when the aroma precursors start turning into aroma compounds. Although the browning stage is after the drying stage, drying continues during the browning stage.
In the browning, the stage begins the Maillard reaction which is responsible for browning. In the Maillard reaction, reducing sugars and amino acids react to make hundreds of different aromatic and colored compounds known as melanoidin.
This is the stage when the roast naturally slows down and some roastmasters like to slow it down too to ensure flavor development. At the end of the browning stage, the coffee begins to erupt. This is called the first crack and the development stage begins.
4. Development Or Baking Stage
In the early stages of development, the reaction becomes exothermic, and the coffee breaks. During the drying and browning stages, the coffee beans have accumulated the energy that makes the coffee explode.
The development time is when the desired aroma compound develops. If we don’t slow down the roasting at the development stage, we easily get coffee that tastes smoky and tastes too pungent.
Cropster can be used to track roasts and profiles
The length of the development stage is usually 15-25% of the total roasting time depending on the flavor profile and degree of roasting desired.
1. Roast degree
How to Roast Coffee Beans Professionally? The degree of roast is one of the most important indicators with roasts. It can be measured with a color meter or by tasting. Roasters usually want to improve the taste of their own coffee and determine the roast level.
Usually, light roasts are more acidic, and dark roasts are more bitter. Also, fruity flavors are more common in light roasts, and roasted and burnt flavors are more common in dark roasts.
Lightly roasted coffee is more fruitful due to the high amount of the organic compound, 5-hydroxymethylfurfural. As the roasting progresses further, these compounds break down into fewer fruit compounds.
The amount of sulfate compounds increases, which results in a roasted and charred taste. As a general idea, we can assume that lightly roasted coffee brings the character of raw coffee better. It is easier to distinguish light roasts from each other than dark roasts.
2. Baking time
Although the degree of roast has the greatest role in the flavor profile of the coffee, the total roast time and the time of each stage are also important factors. If you bake quickly, you will get more of the desired aroma compound.
But be careful not to burn the nuts! The total taste of coffee (fruity, berry-like, chocolatey, totally nutty) is stronger. Also, the amount of aroma compounds, which are created in the early stages of development, is higher with fast roasting.
3. Grill profile for fast roasting
In some cases, quick roasting is not a good idea. It could be because of the roaster design (see the next paragraph below) or the characteristics of the coffee. Quick roasting enhances all the flavors of the coffee.
If we don’t want some flavor in the coffee, we need to adjust the roast profile. For example, acidity is usually the desired taste but in espresso blends, people sometimes want low acidity.
When slower roasting organic acids have more time to decompose, the coffee becomes less acidic. This is when slow roasting might be a good idea.
4. Toaster design
How to Roast Coffee Beans Professionally? There are various roaster designs. Design affects roasting thermodynamics, and it is possible to make different flavors of coffee with different machines.
Small roasters usually use a drum roaster, where the coffee beans are rotated in a drum that is heated under either direct or indirect fire.
This makes the roaster’s energy volume large. Roasting with this kind of machine is very stable, but the roastmaster must be able to think up to a few minutes in advance.
Drum roasters are best when roasting slowly because too high a temperature at the beginning of roasting can burn the coffee beans from the outside.
At Paulig Kulma we use a traditional drum roaster Bertha roaster which is a Probatone 5 coffee roaster.
Mihkel roasting in Paulig Kulma and listening to 1st crack from our Bertha.
In the industry, there have been fluidized bed roasters for ages. How to Roast Coffee Beans Professionally? In a fluidized bed roaster, the roaster is indirectly heated by hot air.
That makes the roaster faster to control. With fluidized bed roasters, it is possible to roast faster without burning the bean from the outside and to get more aroma to the coffee. One example of a fluidized bed roaster is our roaster in Vuosaari roastery.
There are also some hybrids between fluidized bed roasters and drum roasters, like Loring Roasters, in which there is a drum but heating is done indirectly by hot air.
What is roasting coffee beans?
Roasting means turning raw green coffee beans to brown. It’s a complex process that involves heating green coffee beans to transform the basic components within the seed, such as proteins, sugars, and acid into the familiar delightful aromas of malts, chocolate, berries, roasted nuts, and more. Here’s the general coffee roasting process.
How long does it take to roast coffee?
In the first 5 minutes, a high amount of heat will be applied to the beans and bring the coffee up to roasting temperatures. How to Roast Coffee Beans Professionally? Then after another 5 minutes, the coffee will undergo changes at low roasting temperatures (between 300°F and 350°F) developing unique aromas. The final 2 to 5 minutes will develop the coffee’s full flavor.
What happens if you don’t roast coffee?
The coffee bean is similar to a dry pinto bean (speckled bean), which means it can be stored for a long period and still come out fresh when it goes through the process. If you do not roast coffee, the outcome of the drink brewed from the raw beans would be very acidic and bitter, making it undrinkable.
Does roasting coffee beans create a lot of odor?
Finally, roasting coffee beans does create a ton of odor. If you are going to roast them in your kitchen, then be aware of this and open some windows if possible. There are four different types of roasts you should be familiar with. Each roast type will affect the overall flavor of your coffee.
Sumber: nisbets.co.uk and baristainstitute.com