Given that you read our first post on water quality, you are probably now wondering what the optimal water that you can use for your daily brew is. The goal of this article is to explore various sources of water in order to find the one that has the perfect balance of dissolved solids to take your coffee to the next level.
Tap Water
Probably the most readily available and widely varying source.
I am sure you have noticed differences in quality and taste even among different houses in the same city. This is due to a myriad of factors: municipal source, house specific plumbing, pre-faucet treatment, softening and so many others.
The good thing, however, is that the city in which you reside is required to provide a breakdown of what is in the water that they send to your home, so at least we can begin on sure footing. While the reports will vary somewhat on a city by city basis, they should all include information on dissolved inorganic and organic contaminants, as well as hardness, alkalinity and pH. The truly important takeaways here are that all tap water is chlorinated during treatment for drinking and that water hardness can vary greatly from source to source. For example, the water hardness in the 25701 area code of Huntington, WV was measured in 2017 to be 118 ppm which is qualified as moderately hard according to the U.S. Geological Survey. Comparatively, the hardness in Bloomington, IN was measured in 2017 to be 50 ppm, which is considered soft. Taking into account what we learned in the first article on water, Huntington water needs to be softened in order to be appropriate for use in coffee brewing (not to mention dechlorinated), while Bloomington water lies squarely in the acceptable hardness range of 17 to 85 ppm.
Another mark can be made against Huntington tap water for the sodium content which averages 29.8 ppm which is 3 times more than the acceptable range for coffee brewing.
As you can see, the odds are weighed heavily against the tap water available to you at home being your best option when brewing coffee.
Filtered Tap Water
The apparent solution to the issue of tap water quality is then to filter it using a Brita™ or Pur™ water filtration systems, but these have their detractions as well. While the systems do remove chlorine and some other contaminants from water tap water, the pitchers are relatively low capacity and can be a hassle to deal with. Additionally, a study published in 1996 by the US National Library of Medicine found that tap water filtration systems actually increased bacteria counts in the water. When tap water comes from the treatment facility, it has been chlorinated to kill off any harmful bacteria. A possible misconception about water filtration systems is that they kill off or filter out bacteria as well. While this may be the case through the first few cycles of refilling and filtration, in actuality the carbon filter accumulates bacterial colonies that then grow due to the lack of dissolved chlorine, and are then passed into the filtered water. While the SCAA does not provide guidelines for bacterial content in brewing water, I believe it is safe to assume this number should be at or incredibly close to 0.
Another interesting thing to consider is that not all water that comes out of a Brita™ filtration system will be the same. As the input water will vary city by city, so will the output water. Brita™ does provide a performance sheet for their high tier pitcher filter which boasts >90% reductions in lead, mercury, cadmium, benzene, asbestos and chlorine. Notice, however, that neither sodium nor magnesium compounds are filtered out, so output water is around the same hardness as the water from the tap.
So while pitcher filtered water is a step up from tap, we can still do better.
Bottled Water
Now this is an enormous umbrella term as the composition of bottled water varies as much as or more so than that of tap water. Conveniently, bottled water only comes from one of two places, a municipal source or a natural spring. Be wary of your grocery store’s brand of bottled water as it very well may just be purified municipal water and therefore not actually improve your brew. A company that takes this to the extreme is Aquafina™ which takes municipal source water and then filters it using reverse osmosis, producing water that is effectively the same as distilled water. It should go without saying that this is unfit for brewing as you have no dissolved solid material to extract any flavor from your beans.
On the other side of the scale lies spring water which will have a highly variable dissolved solid composition and concentration. Fiji™ water provides an informative report as to the composition of their bottled water.
When compared to the SCAA guidelines, the results are not so promising. Fiji water still has a measure of chlorine in it, and the alkalinity, sodium and bicarbonate measurements are well outside the suggested ranges. If you have noticed this water as having a heavy palate feel, this is why. There is just more stuff dissolved in Fiji™ water.
Bottled water provides a possible step up in water quality from pitcher filtered water, but you must also be cautious here. Most bottled water companies should provide breakdowns of their mineral content for analysis, and in this case, Fiji™ may work alright, but it would definitely need to be left out to dechlorinate first.
Bespoke Brewing Water
The final group considered will be bespoke coffee brewing water. This is water with a mineral concentration curtailed to coffee brewing specifically. To my knowledge, there is only one company that actually provides water treatment packets that you add to distilled water in order to bring it to a desirable concentration. Some brewers have even found this to not be adequate and have instead opted to make their own treatment using baking soda and Epsom salts.
Should you want to try the pre-measured packages, Third Wave Water™ (who I have no affiliation with, I am just a fan) provides packets for both 1 and 5 gallon containers of distilled water. The soluble powder will bring the water to a dissolved solid concentration of 140 with a calcium concentration of 50-60 ppm, magnesium of 70-80 ppm and sodium of 10-15 ppm. These amounts are all spot on with SCAA guidelines, and I find that it does provide an immense improvement in coffee quality from a pitcher filter or bottled spring water.
Should you feel a little more adventurous, there are several articles and recipes online with instructions on what to add to distilled water in order to bring it to optimal concentrations. I do suggest that if you pursue this route that you invest in a dissolved solids meter and hardness testing equipment so that you are not just taking shots in the dark.
So not only is water incredibly complex, but the sources are incredibly varied as well. In reality though, coffee is almost entirely subjective. So if you enjoy your coffee brewed with the water out of your tap, then have at it. I just hope this article helps to open minds to the possibility of better coffee, because isn’t that something we could all benefit from?
Brandon Nylund
Hill Tree Roastery Coffee Education Advisor
https://www.brita.com/wp-content/uploads/Longlast-PDS-with-401.pdf
https://bloomington.in.gov/sites/default/files/2017-06/2017%20Water%20Quality%20Report_0.pdf