Which is healthier dark or light roast coffee?
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Take a look at the picture above. What do you see? Do you see a cherry? Do you think that it is edible?
If you think you can have that cherry, you are badly mistaken. That is actually a coffee cherry. Interestingly enough, most people who drink coffee every day are not educated about coffee at all. They usually don’t have any ideas about the process coffee beans go through to finally end up in your cup. In this article, we want to look at the process of developing coffee beans also known as roasting coffee. We will look at different types of roasts for coffee beans, multiple stages of the roasting process. Finally, we will make some comparisons between different kinds of coffee roasts, especially light roast, and dark roast.
Roasting green coffee beans
The goal of roasting is to strike a balance between sweetness, bitterness, and acidity. Generally speaking, roasting coffee beans is a complicated process of heating, and drying coffee beans inside of a coffee roaster machine, which makes coffee beans transform from green to brown. The reason for this process is simple. Coffee beans are roasted in order to make the properties of green coffee beans undergo physical and chemical transformation. Therefore, the flavors and aromas we desire are achieved in the final cup.
Chemical reactions of roasting
In general, the roasting process removes most of the moisture in the coffee beans and begins pyrolysis. Pyrolisis is associated with a process of temperature decomposition (heating) of organic materials in a situation that the oxygen is absent, this process brings many industrial benefits. Pyrolisis changes the chemical composition of coffee beans and develops compounds related to the flavors and aromas of the brewed coffee. When coffee beans are roasted, 800 to 1000 different aroma compounds are developed.
Who roasts coffee beans?
Before you start your roasting process, you need two important things. A roasting machine or roaster and the even more important one, a roastmaster. Highly skilled roastmasters have the responsibility of roasting coffee beans. These roastmasters or roasters make efforts to apply the appropriate temperature for just the adequate time to produce the best flavors of coffee beans being roasted.
Roasters must be really observant of the color level of the roasting coffee beans. Coffee beans lose moisture and their density changes when they start expanding and changing color. Many of these coffee roasters master the required skills through trial and error. Every roaster has its style and philosophy. However, even they do not always fully understand the complexities of the entire roasting process.
The roasting process of coffee
There are methods and stages for roasting coffee beans. In this part, we enter the world of roasting and find our preference.
There are two major methods of roasting coffee as listed below:
- Drum roasting method
- Industrial hot air method
Drum roasting method
This method is still used in small and traditional companies. In this method, raw green coffee beans are poured into a circular, roaring drum. This drum gets heated by electricity or burning fossil fuels. When the surface of the drum is heated enough, its rotating move transmits the heat to the coffee beans.
This method usually takes between 15 to 20 minutes at 356o to 446o Fahrenheit. The drum method develops the coffee aromas well because of the longer roasting duration and makes the coffee beans more digestible.
Industrial hot air method
Because coffee and its varieties are becoming more and more popular these days, roasters have had to find faster, more efficient ways to roast coffee beans. By utilizing the hot air method, the roasters can save a lot of time and money.
Hot-air roasters are continuous systems. They include a large drilled drum with a spiral conveyer on the side. Using this method a roastmaster can roast one to five minutes before they cool down coffee beans with cold water. The hot air method allows for non-stop roasting of desired quantities of coffee beans although the quality can sometimes suffer considerably.
There are three stages for the roasting process as listed below:
- Drying stage
- Browning stage
- Development stage or roasting stage
Coffee beans are humid at the beginning. The level of humidity is 8% to 12%. Roastmaster needs to dry the coffee beans before they start the actual roasting. This stage normally takes 4 to 8 minutes using traditional drum roasters. In the end, the temperature of the drying stage is 320o Fahrenheit. Roastmaster needs to be really careful because if they have too much heat in the start, they might burn the coffee beans by overheating them.
The drying stage is important for gathering energy for coffee beans because the last stage of roasting is heat-producing.
Passing 320o Fahrenheit, coffee beans start to give out the scent of toasted bread and hay. This is when aroma compounds are starting to be made. The drying process continues during the browning stage although the browning stage actually happens after the drying stage.
Maillard’s reaction starts at the browning stage. The Maillard reaction is a chemical reaction between amino acids. The Maillard reaction reduces sugars and gives browned food its specific flavor. This reaction is the basis for many of the flavoring industry’s recipes.
The Maillard reaction creates hundreds of different aromas and color compounds also known as melanoids. At this stage, the roast naturally slows down. Actually, many roastmasters want to slow the process down in order to ensure flavor development. at the end of the browning stage, the coffee beans start to pop just like popcorns.
Development stage or roasting stage
At the development stage, coffee beans start cracking because the reaction becomes exothermic (heat-producing). During the first two stages (drying and browning stage) coffee beans gather a lot of energy and at the third stage, they are ready to pop. Development time is considered to be the time in which desired aroma compounds are being developed.
Roastmasters slow down the roasting process in order to avoid giving coffee beans smoky-tasting and make the flavor too sharp. The development stage typically takes between 15% to 25% of the total roast time. This time period depends on the desired flavor and roast degree.
First crack and second crack
These “cracks” happen during the development stage. The roastmaster listens to the popping sound of roasting coffee. The first crack happens when the internal temperature is high enough and all the moisture inside the beans starts to explode. The first crack happens at about 385o to 400o Fahrenheit. Coffee beans after the first crack are considered to be a light roast.
The second crack happens when the coffee beans are about 440o to 450o Fahrenheit. After that first crack, there is a short period, which is called “Lull”. After a lull, If roastmaster continues roasting, coffee beans begin to crack again. The second crack is not as intense as the first one but makes coffee beans enter the dark roast territory.
Basic roast levels
Generally, there are five basic stages for roasting coffee beans. Here are more information and some pictures to illustrate the exact shape and color of coffee beans after each roasting stage:
- First crack
- Second crack
- Dark roast
At this level, coffee beans are fresh out of the sack. You can grind and brew green coffee beans, but it will taste more like herbal tea than a cup of traditional coffee.
During the first few minutes, coffee beans remain greenish, little by little they turn lighter and yellowish and give out a grassy scent. At this level, the moisture of coffee beans vaporizes and coffee beans begin to dry. This level is also known as the drying stage we mentioned earlier.
The steam becomes more aromatic and soon after that, you will hear the cracking noises. During this stage, sugar starts to caramelize, water escapes, the structure of coffee beans collapse, and oils come out of coffee beans.
After the first crack, the roast is considered complete. Your coffee beans must be brown. You can use the sound of cracks along with sight and smell the find out the ending of this level. The first crack is also called “City roast”.
The caramelization process continues, oils get out and as the roast gets darker the beans expand. Most roastmasters stop at this point. The second crack is also called “Full City roast”.
As the roast continues to become darker, sugar burns completely and the structure of beans breaks down more. At this level coffee beans are black. This level is also called “French roast”.
Dark roast VS Light roast
In this part, we take a look at one of the most controversial questions. Which is healthier dark or light roast coffee?
There has been an ongoing debate about whether dark or light roast coffee is better. Many people think that dark roast has more caffeine because it is more bitter. That is a common misconception. Only 15% of bitterness is related to caffeine, so dark roast coffee does not necessarily have more caffeine. Moreover, the dark roast has more body, less sweetness, and acidity.
In terms of health, the amount of cholesterol-raising compounds is nearly twice as high in the light roast coffee compared to the dark roast. Roasting destroys some cholesterol-raising compounds. If you want to tackle this problem, you can use paper filters and remove 95% of cholesterol-raising activity. The dark roast also can kill 99.8% of pesticides ingrown coffee. Another study shows that dark roast coffee is more effective in losing body weight when it comes to overweight people.
On the other hand, studies have shown that dark roast destroys nearly 90% of the chlorogenic acids, Which are known as antioxidants or anti-inflammatory phytonutrients.
Roasting is a very vital part of processing coffee beans because it can affect the flavor of the coffee we drink. Now based on the information you got about dark and light roast you can wisely choose the coffee which is healthier for you.
Which roast do you think is healthier? Share your experience with us in the comment section.