The water temperature plays a crucial role in the brewing-process and affects thethe aroma and flavours of the final coffee drink.
Coffee grounds are filled with various oils, acids and chemical compounds. There are soluble and insoluble particles. The soluble particles affect the aroma and flavor and the insoluble particles contribute to the body of coffee.
When the coffee grounds are mixed with water, chemical reactions pull the soluble particles from the grounds.
To brew coffee that we’ll love we have to make sure that our water has the correct temperature.
The water temperature affects the extraction rate: The higher the temperature, the faster the solids are dissolving.
The water temperature also determines which coffee particles get dissolved. If the temperature is too high, unpleasant acids are released from the grounds. With the correct temperature, we will be able to extract the desirable soluble flavor particles from the grounds, and not the bitter and sour ones.
If the water temperature is too cold, the overall extraction of compounds from the coffee will be too weak.
According to the National Coffee Association, the standard temperature for brewing coffee is between 91-95˚C.
For Aeropress, as pointed out by the Specialty Coffee Association, the standard temperature should be between 75-85˚C.
Try to increase the water temperature until it reached the correct level. Boiling water and letting it cool-down afterwards until it reaches the correct temperature will remove oxygen from the water. This will decrease the flavors of the final coffee drink.