Brewing Theory 101: What is Brewing?

It's time to reveal the secrets behind the delicious coffee you enjoy – starting with the art of brewing or making coffee! We will teach you the specific brewing techniques and theoretical knowledge gathered from coffee and industry experts, which goes beyond simply combining ground coffee with hot water. Our Head Barista has a saying: "The best coffee is the one you brew yourself!" After reading this, you'll be the one brewing the best coffee!

Firstly, let's get acquainted with this mystical fruit seed: the coffee bean. The coffee bean’s structure contains the organic and inorganic components which form the building blocks of the beverage we consume. Another equally important element in the brewing process is water, which acts as our solvent, but that's a topic for another article.

The Chemical Structure of the Coffee Beans

Coffee beans can generally dissolve in water at an average rate of 24-28% due to their structure. This is because a significant portion, approximately 72%, of the bean is composed of water-insoluble dietary fibers, specifically cellulose.

The extraction process, which is essentially brewing, is crucial for unlocking soluble compounds, and must occur within specific reference values. Deviating from the ideal dissolution range—whether too low or too high—can result in undesirable and negative outcomes.

The compounds that water extracts from the coffee bean’s structure and are transferred to the cup include:

• Caffeine; is an alkaloid and characteristically imparts a strong "bitter" taste sensation. It is one of the first compounds that begins to dissolve when ground coffee comes in contact with water.
• Acids; the group of acids present in coffee beans primarily contributes to the emergence of fruity flavors in coffee. In addition to the physical structural change coffee beans undergo during roasting, the chemical structural change also plays an important role as the transformation of chlorogenic acid during the roasting process affects the perceptibility levels of other acids. In medium-roasted beans, these acids are present in their most balanced form.
• Melanoidins; Melanoidins actually emerge as a result of both caramelisation and the Maillard reaction during the roasting process. These compounds are responsible for giving coffee its colour and flavour.
• Lipids and Oils; Coffee beans contain insoluble oils. Since water cannot dissolve oils, it acts as a carrier during the brewing process. When brewing ground coffee, water penetrates the coffee particles, transporting the oil groups into the cup. These oils play a significant role in influencing the body and mouthfeel of the brewed coffee.
• Carbohydrates; Carbohydrates are present in various groups within the coffee bean structure. While carbohydrates themselves do not belong to any specific taste group, they are associated with the sweet group. Even though sucrose does not dissolve and emerge as sweet, our taste memory creates a sensation of sweetness. Consider pasta—is pasta inherently sweet? Most would answer no, yet its perceived sweetness is linked to the presence of carbohydrates. Similarly, the existence of sucrose in coffee, guided by our taste memory, contributes to the sensation of sweetness.

In essence, the coffee we enjoy is created through the extraction of these fundamental components. The methods and equipment we employ for brewing, alongside various parameters, play a crucial role in influencing this process.

Brewing Methods

Brewing methods are essentially divided into two categories: Percolation and Immersion.

Percolation:

Percolation refers to brewing methods involving pour-over and manual equipment such as Hario V60, Chemex, Kalita, Origami, as well as auto-drip machines like Moccamaster. In this brewing technique, gravity ensures a consistent and balanced flow through the coffee bed, facilitating the extraction of compounds within the coffee particles. Water is gradually poured in a spiral motion to penetrate the coffee grounds. Before starting, it's essential to create a brewing recipe tailored to your chosen equipment, considering factors like coffee-to-water ratio, grind setting, and water temperature. As filter papers are commonly used, the resulting coffee tends to have a lighter body and more vibrant acidity compared to immersion methods. If you dislike acidic and fruit juice-like coffees, these brewing methods might not be suitable for you. However, you can make your coffee more intense by grinding the coffee beans finer or using more coffee without changing the water quantity.

Immersion:

Immersion refers to brewing methods where coffee is submerged in water and then filtered, as seen in French press, Aeropress, Clever, and Cezve (Turkish coffee). During this process, coffee and water interact in the brewing chamber, allowing water to permeate the coffee grounds and extract their compounds. Subsequently, the brewed coffee is separated from the grounds by passing through the equipment's filter, with the exception of the Cezve (Turkish coffee) method which has its own unique process.

When using immersion brewing, it's crucial to create a brewing recipe based on your chosen equipment, considering factors such as coffee-to-water ratio, grind setting, and water temperature. Typically, metal, or larger porous filters are used in this method, allowing coffee particles to spend more time with water. Consequently, this results in a higher-bodied and more intense coffee compared to the Percolation method. Adjusting the brewing time, grinding your coffee beans coarser, or using less coffee while maintaining the same water quantity can help reduce the body sensation.

Note that espresso, being a distinct brewing method, will be examined separately.