(Note: I may earn a small commission from purchases made through product links in this article at no extra cost to you. Additionally, as an Amazon Associate I earn from qualifying purchases)
Besides the actual coffee that you select to brew with, water is the most important element that goes into a cup of coffee. The mineral content and ph level of the water you use, can have drastic effects on the finished product. Using the wrong water can ruin a beautiful coffee and nobody wants to see that happen.
At the most basic level, water chemistry isn’t a huge deal. Conventional coffee wisdom is, if your water tastes good for drinking, it will taste good for coffee. To a certain extent this is truth.
Here are a few basic coffee water brewing principles, if you think you have a water problem, start here.
If you want to cut to the chase and start with water that is made for optimal coffee brewing, pick up a box of Third Wave Water and see how much of a difference the right water can make to a cup of coffee. (I have used Third Wave Water for several years now.) For the DYIer there is also a recipe for making your own version of Third Wave Water via Tinker Coffee (.75 grams Epsom Salt and .26 grams Baking Soda mixed in a gallon of distilled water).
Make sure you are using clean water that is free of off-flavors and odors. If you wouldn’t drink a glass of it, don’t make your coffee with it.
Filtering your tap water
If you are unhappy with the caliber of your at-home water, the first option that you have is to filter it. The SCAA water brewing guidelines state that water should be clean, odor-free, clear with no chlorine.
Pitcher filters like the Brita use activated carbon to remove some water impurities, odors as well as chlorine or chloramine if they are present. These types of filters are cheap and readily available, however, I have found them to have an annoyingly limited capacity, be cumbersome to use and in constant need of filter replacement.
There are also faucet mounted filters of this type. I have never used them, but they seem like they may be a more feasible option.
For many years, I used a Berkey water filtration system for all my household water consumption needs. Each filter lasts for up to 3,000 gallons and the system has a large capacity (mine held 3 gallons).
Soft or Hard Water?
While there seems to be some debate on the subject, I believe that using hard water makes a better cup of coffee than water softened with a home water softener.
Water hardness is a measure of the amount of magnesium and calcium that is dissolved in water. Water rich in these two minerals (magnesium in particular) are great at bringing out the best in coffee flavoring compounds. Replacing these minerals with sodium will produce a coffee that is flat by comparison.
Very hard water can destroy an espresso machine with scaling and thus it is a large concern in the pressurized coffee game. It has minimal impact on the equipment of a manual brewer. Regular kettle descaling and maintenance should make any scaling from hard water negligible.
One recommended resource that discusses water hardness, testing your water for hardness and water for coffee is Jim Schulman’s Insanely Long Water FAQ. This 17 page document is heavily espresso weighted but has some great general information as well.
According to Schulman, “It’s almost impossible to brew coffee with neutral pH water that’s too hard, since raising it to 95C will drop out the hardness in excess of 90 mg/l to 100 mg/l as scale”
If you have a water softener at home and are feeling incredulous, the easiest way to is to decide for yourself. Try it. Do a comparison test between your soft and hard water figure out which one you like better.
Using Reverse Osmosis Water
Reverse osmosis (RO) is a process where all the minerals are taken out of the water. What is left is water that has virtually nothing in it. You would think that this would be ideal for brewing coffee, but it is not.
Brewing with straight reverse osmosis water will produce a flat cup of coffee not unlike the coffee made with soft water.
Reverse osmosis water is missing all those magnesium and calcium minerals that enhance coffee flavor. There are, however, blending reverse osmosis systems that will mix back in mineral rich water. Some of these systems have the ability to customize the total dissolved solids level of your water.
A reverse osmosis water blend is a viable option for great brewing water. The SCAA recommends 150 mg/L total dissolved solids.
If you do not have a reverse osmosis system with blending capabilities, you can blend the water yourself. Try different ratios of RO water to tap water and see if it improves your coffee taste (20 – 25% tap water is a good place to start).
If none of the above options are feasible or appealing to you, you can always brew your coffee with bottled water. Using bottled water is not a cut and dry issue either. Not all bottled waters are created equal. Bottle waters vary wildly in mineral content, pH and suitability for coffee.
“Bottled waters mostly come in two kinds, alkaline ones with massive mineral levels just below brackish, and acidic ones with mineral levels just above RO flatness. Very few have the intermediate hardness levels found in most municipal waters” (Schulman, 11).
Your best options for bottled water are going to be labeled drinking or spring water. Schulman recommends Crystal Geyser or Volvic. If you are buying bulk five gallon water blended RO jugs, try to locate a source that is using magnesium for adding hardness back into the water instead of calcium (this may be rather difficult).
It’s Going to Be Okay
Don’t freak out. It’s going to be okay. The good news is that most basic water issues are quick fixes and easy work arounds.
While good water is a crucial component of getting the most out of a coffee, adding awareness to the water we use can add extra mental exertion, hassle and expense to brewing coffee manually at home.
If you like the coffee you are brewing at home, there is no need to mess with your water unless you are curious. If you can’t figure out why your coffee is not up to cafe standards, water might be something worth investigating.
Here are a few small things you can do to investigate if your issue is water related:
- Have a brewing party- Have some friends over and brew some coffee. Have each friend bring a different water either from their house or from the store. You can even get crazy and try some waters like distilled for educational purposes.
- Do some cuppings- If you don’t have a lot of people around you that are coffee fanatics, you can get a few different waters and do a cupping on your own. Try three or four different waters side by side with the same coffee.
- Try Third Wave Water- Third Wave Water has been designed as a mineral additive that can be added to distilled water for a optimized brewing water. You can also make your own optimized brewing water if you are feeling ambitious (it is actually pretty simple). Tinker Coffee recommends mixing .75 grams of Epson salt and .26 grams of Baking Soda in a gallon of distilled or reverse osmosis pure water.
- Ask your barista- Is there is a particular coffee shop that brews coffee you admire? If you can’t seem to replicate the experience at home, ask the coffee shop if you can have some water. This may seem like a strange request but explaining to a barista that you are trying to diagnose your at-home brewing should clear up any issues. Most baristas would love to give you a sample I’m sure.
This really just scratches the surface of water chemistry. For further reading you can check out the links below. Something that is also very interesting and will hopefully be the topic of a future post is Maxwell Colonna-Dashwood’s Symposium talk about water chemistry and mineral content. I found this fascinating and have some definite ideas and thoughts on the matter.
What if your issue is not water related at all? Check out Troubleshooting and Fixing a Bad Cup of Coffee for my tips on coffee fixes.
What about you? Do you have thoughts on brewing water or methods for making sure your water isn’t holding back your coffee’s true potential? Let me know below.
(Originally Published June 16, 2015- Updated September 10, 2020)