There is no escaping the fact that all coffee beverages are made up of at least two ingredients — the coffee itself, and water. Although it’s a topic we have covered before, it’s still one that is widely neglected and rarely considered when troubleshooting quality issues. Not only is water one of the only two ingredients required to create a coffee drink, it also accounts for nearly 95% of your final beverage. So, rather than considering water as a facilitator in turning coffee into liquid, it really needs to be considered as a crucial ingredient that has enormous influence on the final taste.
After doing some very basic water analysis at our lab in Melbourne earlier this year, it became clear that some areas are ‘naturally’ better set up than others. The tap water’s TDS (total dissolved solids) reading sat comfortably around 100ppm and the water showed no signs of unpleasant foreign flavours. According to industry standards, this falls neatly in the recommended parameters of 100-200 ppm TDS for brewing coffee, and therefore may well add some validity to the claims that coffee tastes better in a certain city, area etc. To that I say, good for you Melbourne!
Now back to Perth, somewhere I call home and know very well. Unfortunately I didn’t have the same luck with water coming out of my home tap. My TDS reading was through the roof; 500+ and with a distinct chlorine taste that I can only guess is a product of treatments our local water has to undergo in order to be safe to drink. Total Dissolved Solids represents the total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water. Hence a high TDS reading from the tap can mean the water is oversaturated, meaning that dissolving coffee solids successfully is difficult. If your water is already ‘full’, extracting the best from your coffee becomes less likely.
This is consistent with the results I had with the coffee coming out of my espresso machine ‘pre reverse osmosis’ installation. Knowing full well that I had all the ‘flavour influencing parameters’ checked off (e.g. grind quality, dosing, temperature, dose, distribution etc), I was able to link my poor results directly to my water quality and high TDS reading. No matter how well I knew a particular coffee, and how aware I was of how it ‘should’ taste, the results I had were all very similar; heavy and flat, with very few distinct characteristics coming through. Boring would be an accurate description. The unfortunate story for those of us with average water coming out of our tap is that treatment options are rarely straightforward or cheap.
Before installing our Reverse Osmosis system at home, we took our machine apart and de-scaled the boilers as well as other various bits and bobs. The moment we ran treated, 70ppm TDS water through our machine, the difference was startling. Coffees tasted as I knew they should. They showed distinct character, heightened sweetness and added layers of complexity and intensity. We added an extra tap to the same Reverse Osmosis system so that we had a good water source for our filter coffees, as well as our espresso. The result? Coffee at home has never been better. Sweet!
We did a small test today with Pure Water (6ppm), Reverse Osmosis water (60 ppm) and Perth tap water (500+ ppm). (We opted not to use a Brita Filter for this experiment because it gave us the same TDS reading as tap water. Because our experiment is based on the TDS variable, we saw no justification for using the Brita.) Not surprisingly, we found a significant taste difference between the three. Apart from changing the water, we used exactly the same brewing parameters. In a blind test, the R.O. water tasted significantly better; the Pure Water tasted weak and thin, while the tap water was chalky and flat.
In summary, water quality really is important and the solution is not always an easy one. However, depending on how serious you are and how determined you are to get the best out of your home set-up, doing some small experiments with different water sources can help uncover flavour that’s been right under your nose this whole time.