You know we love a good blog post about coffee. But there's an important and overlooked ingredient comprising 98% of your cup: water! The type of water you use to brew can make your coffee tasting notes sing or fall totally flat.
You may not realize it, but almost every player in the beverage industry fusses over the water that goes into their products. Beer, soda, tea, and even the diluted portion of spirits all have industry and company specifications for what the chemistry of their water should be.
Here's why: water holds onto the dissolved minerals with which it comes into contact. Every part of the world has a different tendency for the dissolved mineral content in its public water source. Here in Denver, we have hard water because the groundwater comes into contact with limestone. Beyond the overall amount of dissolved minerals, there's variation in the amount of each element (such as sodium, potassium, calcium, etc.) which further affects taste and interaction with other ingredients in your beverage.
Is my tap water okay for brewing coffee?
In the coffee industry, we focus on the overall mineral content of the water, with a target of 150ppm (parts per million) of TDS (total dissolved solids) and an acceptable range of 75-250ppm.
Think of your water like a sponge that can absorb a limited capacity of “stuff” into it. The more stuff that's already in your sponge, the less capacity it has to absorb something new. So the more dissolved minerals in your water, the more difficult it is to absorb coffee into it.
Your local tap water may be anywhere from ideal to wildly inappropriate for the best brew. Look at the map below to get an idea of the type of water you have.
If you're close to that 150ppm target, you're in good shape! If not, here are a few methods to get great water for brewing.
Option 1: In-home water filtration
This is an ideal solution but also the most costly. Home water filtration solutions can be as simple as a carbon filter (like a Brita filter), or as complicated as a reverse osmosis (RO) system.
Carbon filters remove unpleasant odors or tastes, but they typically won’t change the mineral content. On the other end of the spectrum, RO removes everything and should be supplemented with tap water to establish a balanced mineral content. If you know that the water in your area is high in mineral content, you can simply mix half distilled or RO water with half tap water and get a good result.
For those who want to be a little extra, new filtration products like the Peak Water pitcher replicate cafe-grade water at home.
Option 2: Purchasing water
You can purchase gallons of water at your grocery store for a very low price and use them just for coffee. However, we want to emphasize the importance of reusing your jugs! You can usually bring them back to the same store for an easy and inexpensive refill.
The key to buying water is to know that you're getting something different from your tap. Some resources lightly filter the same tap water you have at home, so make sure it is distilled or filtered through reverse osmosis.
Again, be sure not to use pure distilled or reverse osmosis water alone as it tends to make your coffee sharp or bitter. Mixing half distilled water with half spring or tap water works well, particularly if your tap water has high TDS.
As an alternative to mixing water sources, you can supplement pure distilled or RO water with powdered minerals. A product on the market called Third Wave Water is new to the home coffee-making scene. It adds the right amount of minerals to bring distilled or RO water into the realm of perfect for brewing.
By playing around with your water, you might notice some unpleasant tasting cups of coffee. Don’t fret! Altering your mineral content alters your coffee extraction rate and therefore flavor profile. With filtered or “constructed” water, you are now opening up space for more coffee particles. Go ahead and experiment with the amount of ground coffee per cup to find your happy place!
The bigger picture: water and the coffee industry
The entire coffee process, from seed to cup, depends on water. Coffee plants require it to grow, coffee mills require it for the wet milling process, and retailers and consumers use water to brew the final cup. A study conducted by the Water Footprint Network estimates that it takes 140 liters (37 gallons) of water to produce a single cup of coffee, which was also validated by a Dutch study. Coffee is a water-intensive product.
We recognize our privilege in being able to curate our water to create our perfect cup of coffee, while some populations in coffee's origin countries worry about having access to any water at all. In selecting the growers, producers, and other partners we work with, we choose those with demonstrably sustainable practices including water conservation.
The next time you sit down to enjoy a fresh cup of coffee, remember to give thanks to the wonderful water that made it possible!