The importance of waterUpdated 14 days ago
Water makes up more than 98% of a black brew, and around 90% of an espresso, so the water chosen makes a huge difference to all aspects of the final character of the brew.
Read about different aspects affecting your brewing below:
Mineral content
The balance and level of the water’s mineral content makes a huge difference to what we are able to extract from coffee. Dissolved minerals in water exist as charged ions, which help us to bind to the flavour compounds in coffee that lead to the most exciting and involving cups. For coffee brewing, we can think of these minerals existing in two broad categories, General Hardness (GH) and Carbonate Hardness (KH). For natural water hardness, the two most important GH ions are Magnesium and Calcium. Magnesium has a very strong attraction to natural acid molecules, so has a huge effect on perceived acidity in coffee, pulling out flavours we like to describe as fruits in coffee, normally sharper acidities like citrus and forest berries. Calcium has a slightly weaker interaction, so tends to enhance softer acidities like strawberry and cherry, while also directly enhancing body.
Controlling KH
The final piece in the puzzle is KH, which has a slightly more complicated interaction. Through a phenomenon known as buffering, the carbonate hardness tries to keep the pH (the scientific measurement of acidity) of the water around 7, which is neutral. This means that controlling KH is very important. Too little, and the coffee tastes unbalanced and sharply acidic, no matter what brewing parameters are changed. Too much, and it is impossible to perceive any acidity in the coffee, leaving a flat and dull cup.
Water Temperature
One aspect that can affect the overall expression of the cup is the water temperature that you brew with. The hotter the more you will extract from the coffee, both the good and bad and vice versa. In simple terms we recommend using a hot temperature like 96-98C for our coffees when perfectly rested, but if the coffee is a bit fresher a lower temperature, like 90-92C will result in more balanced cup. furthermore a lower temp will give a bit more sweet and arguably muted cup. We also like to recommend to use lower temperatures for Anaerobic coffees since they can become overpowering and unbalanced in their funky flavour profile.
Brewing materials
One last thing to be aware of is the brewing material you are using, plastic brewers keep the coffee hotter, so a temperature of 98C might be a bit too hot. Glass and ceramic is in the middle, we like to use 98C here. With materials like copper and metal we sometime find the best balance with 100C water since the metal absorbs so much heat from the brew.