Coffee preparation and brewing is the process of turning coffee beans into a beverage. Particular steps completed vary with the type of coffee and the brewing method to be used. Four basic steps are usually used which are: raw (green) coffee beans are roasted, the roasted coffee beans are ground, the ground coffee is then mixed with hot water for a certain time and liquid coffee is obtained.
Some of the terminologies used in relation to coffee brewing include:
Pre-infusion- process where hot water is applied on ground coffee for an initial period. It displaces air bubbles in the coffee bed causing moistening for better coffee extraction.
Brew ratio - weight of the coffee grounds used in relation to the weight of water applied in brewing coffee. Various brewing methods have different brew ratios.
Brew time - amount of time from the initial introduction of water to the ground coffee until the final drop of brewed coffee is obtained.
Dose - amount of coffee grounds used in the recipe to brew a particular cup of coffee.
Brewing coffee involves various subcategories of brewing methods, commonly referred to as immersion and percolation.
Infusion is the process of extracting flavors and other chemical compounds from coffee grounds by allowing them to be suspended in water over a certain period of time. This process is also called steeping. Two equipments with this method of brewing are the French press and cold brew.
Percolation is the seepage of a liquid through a porous substance. It takes place every time a fluid flows through a porous medium. Percolation involves two methods which are; percolation by gravity and percolation by pressure. Equipment that use gravity percolation are chemex, V60, napoletana and the water dripper. Equipment that use pressure percolation include; siphon, aeropress, moka and espresso machinery.
The French press was invented in France in 1857. It is also known as Melior, cafetière à piston or plunger coffee. This preparation is known worldwide with the name of its country of origin.
During preparation of coffee using a French press, the following parameters should be taken into consideration
- Water temperature-92°C
- Water dose-300g
- Coffee dose-15g
- Coffee to water ratio-1:20
- Grinding size- 7
- Infusion time- 3 minutes
- Heat the water in the kettle to a temperature between 92 °C and 96 °C.
- Pour a little water into the French press to warm it, then remove the water.
- Put the recommended amount of ground coffee into the jug.
- Pour in the correct proportion of water and mix.
- Cover the jug with its lid, but leave the plunger up.
- Wait between 2 and 4 minutes. The infusion time affects the final taste.
- Push the plunger down slowly, using gentle constant pressure, until it reaches the bottom of the jug.
This is a long and cold extraction. It seems to have originated in Japan in the 1600s. According to another legend, the first cold brew appears to have been made in 1840s, when coffee syrup mixed with cold water used to be served to French soldiers to fight the heat in the Algerian desert.
During preparation of a cold brew, the following parameters should be taken into consideration:
- Water temperature- Room temp
- Water dose-900g
- Coffee dose- 60g
- Coffee to water ratio- 1:15
- Grinding size- 7
- Infusion time- 8 to 12 hours
- Fit the filter into the cold brew jug.
- Put the correct quantity of ground coffee in the filter.
- Add the recommended quantity of cold water.
- Wait until extraction is complete (at least 8 hours) and remove the filter with the coffee grounds.
- Serve the coffee in a glass with 3-4 ice cubes.