We have written about the importance of the process that goes into achieving the perfect cup of coffee. From cultivating the plants, to picking and processing the ripened cherries, we are keen to explore all the factors that make coffee the deliciously addictive beverage for which it is known. One of the most important factors in coffee processing is the roasting method. Over the course of several centuries, roasting has become both a science and an art. Beginning in the Ottoman empire where perforated pans were held over hot coals, all the way to present-day industrial roasting machines which can handle large enough volumes to satisfy a small village, the process has evolved to give us different roasts that each boast different flavour complexities. Roast preferences are largely dependent on specific regions as well as the regions’ own coffee cultures. In America, medium roast is the most popular whereas in certain regions of Europe and the Middle East, people prefer a darker, full-bodied coffee. The roast can also depend on the coffee bean itself, since certain beans are at their most flavorful when lightly roasted whereas others are the opposite.
The roasting process differs with each method. While there are many ways to achieve the desired roast, today we will focus on the most popular methods. Most of the well-known coffee brands that we can purchase at grocery store chains are usually from beans that have been roasted using the industrial method. Manufacturers invariably use one of the following roasting machines: drum or hot-air. A drum machine ensures that the beans continually circulate as heat emanates from the bottom, slowly roasting them to the desired level. The most popular machine today is the American-made Diedrich infrared drum machine.
Hot-air machines on the other hand function a little differently; they work by pushing heat through a perforated screen. The beans are placed on the screen and the hot is pushed through the bottom with enough force so that the beans lift and tumble repeatedly.
Another notable coffee roasting method is the Vietnamese process. Since its introduction in the mid 1800s by the French, coffee has become wildly popular and today, Vietnam is the second largest coffee exported in the world.
Vietnamese coffee usually tends to be a dark roast since Robusta beans are grown in the country’s highlands. The beans are slow roasted at a lower temperature, oftentimes in clarified butter and a touch of sugar. The oily coating ensures that the beans are easily turned during the roasting process since the Robusta cherries ripen slowly, meaning that some of the beans may not be as ripe as one would desire during the harvesting period. The slightly unripened texture can make an evenly roasted bean difficult harder to attain, hence the butter coating. The sugar added also ensures further caramelization, resulting in what is known as a “butter roast”. The other aspect that makes Vietnamese coffee quite different than all the others is the addition of different components during the roasting process.
Flavours such as chicory, vanilla or cocoa are added during the roasting to give the coffee a distinctive taste.To go back to the different types of roasts as mentioned in the beginning of this article, they are largely determined by the roasting duration as well as temperatures. While there are different names attributed to the different roasts, they are broadly classified by the following: light, medium or dark. Light roast coffee is often referred to American or New England roast.
The flavour is distinctly close to the original flavour of the bean. This is because the bean has not been exposed to the heat long enough for its natural sugars to caramelize. Therefore, the tangy hints of fruitiness and sometimes an almost floral scent tend to prevail one brewed. Achieving a light roast takes several minutes; the roast is completed once the bean is at approximately 196 °C and pops and expands in size. A common misconception of the light roast is the caffeine level; light roasts have higher amounts of caffeine than do the darker roasts. Caffeine levels actually diminish in a bean when it exposed to more heat.
The ever-popular medium roast is also commonly known as the city roast. It is preferred by many coffee drinkers due to its middle-of-the-road flavor. It does not harbour the acidity of the light roast since the natural sugars have had time to caramelize due to the extended roasting time (the sugars subdue the tanginess) nor does it retain the light consistency; the longer roasting process gives it more body. Unlike the light roast where the bean is taken off the heat after it has first popped, the medium roast is achieved by keeping it on the heat for a few minutes longer.
This brings us to the dark roast. Also known as French or Full City roast, the bean is kept on the heat for a longer period of time until it reaches 224 °C and pops a second time and its own oils come up to the surface. Therefore, not only is it darker in color, but it is shinier as well due to the oil. The taste is also distinctive; rich and robust, the original flavour of the coffee bean is replaced with the bittersweet boldness that only the prolonged roast can achieve.
If you are wondering whether espresso falls into the category of the dark roast, you would be half right.
The espresso is considered a double-roast; the temperature is higher than all the previously mentioned roasts and the end result is a dark, near-black coffee bean with a higher solubility level and rich, smoky undertones in taste.
Coffee has certainly evolved since the aforementioned Ottoman empire. While the different types of roasts result in different beverages, what has remained unchanged is the fact that every coffee drinker has their unique personal preference. An individual may favor the fruity undertones of a light roast, sweetened with a spoonful of sugar, whereas the next person will opt for a tiny cup of strong, black espresso, untouched by any additional flavours. What both people will agree on, however, is that coffee is invariably an essential and irreplaceable part of their daily routine and that they would be loathe to miss out on it!
