WaterThe role of water in the brewing process is crucial in creating a great cup of coffee. Water acts as a solvent during the brewing process, extracting the flavours present in ground coffee. The chemical makeup of your water can positively or negatively affect this process. Taking some very simple steps in choosing the right water, will have a significant impact on the quality of your brewed cup.

Aside from zero flavour taints (removed by devices such as a carbon filter) and a relatively low mineral content, the major factor to overcome is hardness. Water hardness is a measure of how much limescale is dissolved in the water. Different areas of the country will have varying levels of hardness due to their local geography. This link to Yorkshire Water will allow those in Yorkshire to test their area by local postcode. The level of hardness affects how solubles in your ground coffee actually make it into a solution – your cup of coffee. Through much experimentation, it has been shown that a small amount of hardness is desirable, but anything above a moderate amount negatively effects the extraction process.

Here in Hull, we have hard water. Very hard water! Therefore, the only way to successfully brew speciality coffee is to use bottled water. I have done tests in the roastery to compare tap water, carbon filtered tap water and bottled. The chemical results show that even carbon filtering has very little effect on reducing the hardness of our Hull water. Use bottled, please!

In order to choose the right water, the Speciality Coffee Association of America has published guidelines for what is commonly thought of as the perfect water for brewing (see table). You will find these values printed on the side of each water manufacturers bottle. In the roastery, we use Volvic.