People have been drinking coffee for hundreds of years. The earliest evidence of coffee being roasted and brewed goes back to the 15th-Century in Yemen (Weinberg et al., 2001). They simply roast and ground the coffee before throwing it into a pot with hot water.
Over the years, the methods used to brew coffee have evolved considerably. While some cultures still use very simple brewing techniques, others have developed elaborate machines that are carefully designed to create the perfect cup coffee! In this article Arik Weiss, CEO and Founder of London based Doppio Coffee will examine the most common brewing techniques that can make a delicious cup of coffee.
Coffee Brewing Techniques
There are several methods for brewing coffee, but they can all be classified in one of four ways:
• Decoction (Boiling)
This is the technical name for extraction via boiling. Coffee grounds are placed in boiling water to extract their flavour.
• Gravitational feed (Filtering)
Coffee is usually placed in a filter of some kind and hot water is poured into in. The hot water extracts the flavour and seeps through the filter. Percolators and drip brewers use this technique.
• Infusion (Steeping)
This is the process of gradually extracting flavours from the coffee grounds by placing them in a solvent like hot or cold water. A French press uses this method.
• Pressurised Percolation
Pressure is used to push hot water through tightly compacted coffee grounds. This is the technique used by espresso machines.
Perhaps the simplest brewing technique, mixing boiling water with coffee grounds has been used by various cultures for hundreds of years. It is still a popular way to prepare coffee in the Middle East, Indonesia and some Nordic countries.
Ideally, the grounds will be mixed with the hot water long enough to allow the flavour to emerge without drawing out any bitter compounds. The key to preventing bitter compounds being extracted is to keep the water just below the boiling point.
Some of the common techniques for making coffee using decoction include:
• Mud Coffee
Finely ground coffee is placed in the bottom of a cup, then freshly boiled water is poured in. The drinker then waits for the grounds to sink to the bottom of the cup before consuming their drink. This is a common way to drink coffee in many parts of Asia.
• Turkish Coffee
Finely ground coffee is placed in a pot with a narrow top (called a cezve in Turkey). Sugar may also be added to the pot and it may be flavoured with cardamon. It is brought to the boil, then removed from the heat. It may be brought to the boil on a few occasions. Traditionally, Turkish coffee is then poured into small cups. This is a very old technique for brewing coffee and is used in many countries throughout Africa, the Middle East, the Balkans, and Russia.
• Cowboy coffee
This method uses coarse-ground coffee beans that are immersed in a pot and heated until boiling. The pot is then taken off the heat and the grounds are allowed to settle in the bottom of the container.
Gravitational Feed (Filtration)
This category includes a variety of devices that use gravity to push water through a filter that holds coffee grounds. Some of the devices include:
• Neapolitan flip coffee pot (Stovetop percolator)
The bottom of this device holds a reservoir of water, there is a filter in the middle holding the ground coffee and a chamber in the top to receive the brewed coffee. The device is placed on a stovetop to heat up. When the water boils, it is pushed up a spout, soaking the coffee and emptying into the top chamber.
• Electric percolators
This is a very popular device in western countries. Coffee is placed in a paper filter and placed into the machine. A container is placed beneath the filter to catch the coffee. The coffee machine drips hot water onto the coffee filter, soaking the coffee. The filter allows the brewed coffee to flow through, but not the coffee grounds.
• Cold brew coffee
Coarsely ground coffee is placed in a large container with cold water. The coffee is allowed to brew in this cold water for a very long period — usually between 8 to 24 hours. The coffee is then drained through a filter to remove the coffee grounds.
There are many commercial products on the market that use the filtration method for brewing coffee. They include the Hario V60, Chemex, Kalita Wave, the Walkure Bayreuth Porcelain Pour Over Brewer, and the Kone. These devices use uniquely shaped filtration systems with the goal of achieving a better cup of coffee.
Steeping involves letting the coffee sit in hot or cold water for a set period to extract flavour from the coffee grounds. The most famous device for the infusion brewing of coffee is the French press. It is a tall and narrow cylinder that comes with a plunger that has a fine mesh filter.
The coffee grounds are placed into the container with the hot water, then after a few minutes of brewing, the plunger is used to push the coffee grounds to the bottom of the device. The coffee can be poured out while the plunger holds the coffee grounds at the bottom of the container. Other variations of infusion brewing include:
• Coffee bags
Similar to tea bags, they are simply immersed in the water for a few minutes, then removed.
• Sock brewing
In some parts of Asia and South America, a sock is used to hold coffee that is steeped in hot water. In many cases, the sock is reused multiple times.
This technique involves hot water being pushed through coffee grounds under pressure. It is the most common form of coffee brewing performed in coffee shops throughout Western countries and is know as “espresso”. Other methods that use pressurised percolation include:
This is a handheld, non-electrical device that uses pressure to push medium-temperature water through coffee grounds.
• The Moka Pot (Italian coffeepot)
This is a three-chamber pot with water in the lower section and coffee in the middle. As it boils, the pressure created by the steam forces the water upwards, through the coffee grounds and into the third section.
Many of these methods can create coffee with a unique flavour. It is worth experimenting just to find out how different each method makes the coffee taste!
Thanks for reading!
written by Ran at doppiocoffee.co.uk