You may not have put much thought into it, but water is a major component in espresso coffee. Colonna-Dashwood & Hendon (2015) have a comprehensive text dedicated to just this and state “Water can transform the character of coffee. It can accentuate its acidity, or wipe it out entirely. It can increase or decrease body, change extraction and much more. It affects the way we roast and the way we brew”. This topic is complex and intimidatingly scientific, yet here is our attempt to break it down into a palatable piece for you to enjoy.
You may already have heard of the concept of ‘hard’ water and ‘soft’ water, high mineral content is referred to as hard and low mineral content is soft. The minerals that create hard water are Magnesium and Calcium. Water high in these minerals may create scale build up; however filtration equipment can remove the temporary hardness that may cling to and do damage to a machine and its ability to produce top-quality espresso. For this reason, high mineral content water that is filtered may be better described as ‘full’ in place of ‘hard’.
Water high in Magnesium or Calcium has a negligible flavour difference between them potentially positive or negative dependent on their impact in concert. Distilled or deionized waters do not produce flavourful coffee, as there is nothing for the coffee compounds to cling to. So too, high mineral content water may create a coffee that is flat, dull earthy or chalky; as it is already saturated with minerals leaving no room for coffee flavours and oils to be extracted into it. A high mineral content water that is balanced has the ability to enhance coffee creating a bold cup with more acidity.
Reverse osmosis or cartridge filters may offer a good method of controlling water quality. Altering the levels of minerals as well as nitrates, sulphates and anything else floating within it. Reverse osmosis strips everything from the water and then re-introduces desirable minerals in precise increments, while keeping unwanted elements out. Cartridge systems use an ion exchange process through a carbon block, that removes chlorine and organic material. This method can alter the pH level of the water passed through it (that varies from location to location) so review of this is important. Keeping water quality, minerals and pH as constant as possible through filtration will make for a desirable cup. Overall, cartridges are generally the more cost effective solution for water filtration in operation.
Overall, water quality is vital to coffee extraction and brewing and controlling this can greatly enhance the flavour of your espresso. Other benefits include maintaining your machine and ensuring its longevity. Adding another element in the espresso process to be aware of – your water source and its filtration bears much greater attention and respect for the future of espresso.
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