Coffee is a term relating to the beverage that is an essential part of everyone’s life as it provides the fuel or energy we need to conquer the day’s task. However do we actually know what is coffee and how it is made? We tend to take the process of making coffee for granted because at times we are always on the rush and consumption of the coffee often occurs without us pausing to think about what coffee actually means.
I have had the privilege to take part in a Coffee Theory & Tasting session conducted in NUS by the co-founder of The Coffee Roasters. Swee Heng. The Coffee Roasters which was founded in Feb 2014 has now grown into one of the highest volume specialty cafes in Singapore. As an introduction to the workshop, Swee Heng kindly presented as with 2 cups of coffee and urged us to describe the taste and aroma that we can detect and how it varies from each cup.
As seen in the photo above, the 2 cups seem visually the same based on colour and texture, however drinking and smelling the 2 cups, there was a distinct difference in the 2 types of coffee. The coffee in the cup labelled C had a more Herbal/ Hazelnut taste with a slight sour aroma whereas the coffee in the cup labelled E has a bitter aroma with a sweeter and fruity taste to it. Cup C coffee is brewed using Coloumbian Coffee beans whereas Cup E coffee is brewed using Utopian coffee beans. This small tasting session has demonstrated the fact that the compounds found in the coffee beans remind us of certain food items. There are generally three main types of coffee beans in the world: Arabica, Robusta and Librica. Such coffee beans are often grow in countries along the region known as the ‘Coffee Belt’ such as Colombia (South America), Ethiopia (Africa) and Vietnam (Asia Pacific).
Coffee Myths and Facts
Another interesting takeaway from the workshop was finally being able to understand why there are so many different types of coffee found on the Starbucks menu. In a nutshell, there are mainly two categories of coffee: Black and White coffee. Starting off with black coffee which consists of Americano and Long Black which to me seems like the exact same drink. In actual fact, there are made with espresso but differ in the preparation process. The intriguing thing to me was that a simple reverse of order in the addition of hot water to espresso could result in two types of coffee which may look the same but taste slightly different. Moving on to white coffee which is the type of coffee that I normally go for, there are in fact three types: Cappuccino, Flat white and Latte. These three coffees vary largely because of the ratio of foam to coffee. I have been told that people tend to stick to one kind of white coffee but after attending this workshop, I am more interested in trying out other white coffees and comparing their texture and flavour.
Espresso and Extraction Theory
The ideal taste coffee among people tends to be something along the line of sweet, nice mouth feel and good after taste, all these characteristics can be achieved through certain modifications in the extraction process. The definition of extraction can be said to be everything that the water takes from coffee. An important component of the extraction process is the Brew Ratio whereby it is essentially the ratio of the mass of coffee grounds to that of the liquid espresso in the cup. The variation of Brew ratio will result in the the difference in the amount of liquid coffee produced at the end which affects the flavour and texture of the coffee. Another factor that affects extraction process is the Grind Size of the coffee grounds extraction efficiency of the coffee beans. There is no ideal grind size to use as it varies based on the brewing method because not all methods require high extraction of the coffee beans. Other factors also include: Brew time (Duration of coffee immersion with water), Brew temperature ( Amount of thermal energy supplied to the coffee grounds), Pressure ( Increased pressure increases extraction but no change observed at high pressures) and Water hardness (Presence of ions in the water)
Compounds present in coffee grounds
Extraction of coffee beans can either be over-extraction or under-extraction which results in the variation in the compounds that are extracted from the coffee beans. Coffee beans tend to contain compounds namely: Caffeine, Acids, Lipids (Fats), Sugars and Carbohydrates starting with the most soluble. The final taste of the coffee is dependent on the degree of extraction which affects the compounds that will be present in the coffee at the end. This is why coffee that is brewed at local coffee shops tend to be more bitter and dry is due to the common practices among drink stall owners to over-extract in order to get as much out of the coffee grounds. But this will result in the carbohydrates (including plant fibers) that will get extracted which give local coffee the distinct bitterness.