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Matt Brown

One Filter to Rule Them All: The Best Water Filter for Coffee Brewing

The journey of water down a mountain, through the soil, and into your local aquifer will change the taste of the coffee you brew.


Water is known as the ‘universal solvent’ for its ability to dissolve more substances than any other liquid. As a result, throughout its life cycle the chemical composition of water will change as cations and anions are dissolved and absorbed and the mineral content fluctuates. This, coupled with differences in each municipality’s water treatment plants, creates a chemistry unique to each region. Meaning the tap water from your home may taste drastically different than that of other regions - or from that of your favorite local cafe!


This distinctive chemistry interacts with coffee’s flavor and is why one of the biggest challenges to creating cafe-quality coffee at home is the water you use to brew.


Our cafes are situated in three distinctive water catchment areas (Tahoe, Reno and the South Bay), which means we have to use different water filtration systems in each market. This keeps our coffee tasting great, and, believe it or not, protects the life of our brewing equipment too.

So what can you do at home? What water filter is best for your Coffeebar coffee? While it’s important to filter your tap water in general, each type of filter is selective in what it’s treating. To understand this complexity requires us to dive deep.


Down the Rabbit Hole: The Experiment


*An important caveat before we get started: Coffeebar has no affiliation with any of the water filtration companies that were evaluated in this test. We purchased these water pitchers based on their advertised difference in water treatment.

For this experiment we took a gallon of tap water from our stores in each region and started by measuring each sample’s basic composition. We then filtered the water using three different at-home filtering technologies (pitcher style, no plumbing required!) and used the filtered water to brew coffee. Our goal was to see which filter made the best water for coffee in each region, so you can choose the filter that works best for you!


And Our Contestants Are…


The types of filters we used were:

Carbon filter = removes organics, aromas, chlorine. (Hydros)
Carbon filter + softener = all of the above + reduces calcium and some heavy metals (Brita)
Carbon filter + softener + remineralization (technology made specifically for coffee!) (Peak)

As a control we also used:

Tap water
Third wave water (a mineral sachet you add to distilled water)


Conducting the Taste Test


Water chemistry will impact coffees with different roast levels in different ways, so we used our filtered samples and the two control waters to brew both our Colombia Agualinda (light-medium roast) and our Giuseppe blend (dark roast). We then asked our panel of tasters to rank the brews in terms of overall preference for each region.

We did a round of tasting for each region’s water, three separate rounds in total. In order to eliminate biased results, we conducted the evaluation blind, meaning none of the tasters knew which coffee was brewed with which water, or what region the water was from. We followed the standard SCA cupping protocol, minus their water quality standards, which is our usual method for evaluating coffees.

So… What did we find?


Drumroll please…


Colombia Agualinda Results



This graph gives you a more visual representation of our preferences overall. You’ll notice that even though


The winner in all markets was the Peak Water Pitcher!

The Peak Water Pitcher’s technology is specially designed to make perfect water for coffee, no matter your tap water’s starting point. It uses an adjustable multi-stage filter that first removes chlorine and other unsavory additions from municipal water treatment and slightly softens the water, before a second cartridge re-mineralizes the water with calcium and magnesium, which have been shown to aid coffee extraction. It even comes with a test strip to help you find the right setting for your water!

But if you’re travelling and carrying a full-size water pitcher isn’t an appealing option, or if you don’t want your home results to be subject to seasonal fluctuations in your tap water, our results point toward Third Wave Water as a solid (and more portable option). Because the idea of Third Wave Water is to build a great water for coffee extraction from scratch, we used it as a control for our experiments. While it was never our favorite cup, it also never produced a bad brew.


The Hydros and Brita filters had varying results, but we did end up preferring both filters over tap water overall.

So we can say that in most cases, filtering your water with any filter is better than not filtering at all.

Giuseppe Results



You’ll notice that this chart is quite a bit simpler. When our panel tasted the Giuseppe brews, we couldn’t objectively pick apart the differences in flavor enough to make a solid, qualitative assessment between the different filtration methods. However, we did see a significant difference between each region’s water overall, so we ranked those instead. It doesn’t tell us too much really, but our rankings do correspond with the overall hardness of the water in each region, with the South Bay having the softest water and Truckee the hardest.

However, these results come with an important caveat: the members of our tasting panel primarily drink medium to light roast coffees. The Giuseppe brewed using softer water from South Bay presented more floral and bright tones, which is certainly this panel’s preference, and which usually correspond to higher scores when cupping. If you prefer the classic dark roast flavor profile that has more of an earthy/smokey/slightly bitter edge to it, then you would most likely enjoy this coffee brewed with water from Reno or Truckee.


Our Recommendations


If You Drink Light to Medium Roasts


South Bay


With much of the Bay Area’s drinking water being fed by snow melt, the water is very pure and low in mineral content. Regardless of the filter technology, you just can’t achieve the same complexity of flavor as when using water with slightly higher mineral content.

Therefore, we recommend you do the same thing we do in our Redwood City café: use a filter technology that adds minerals back in. Of the technologies we tested, the Peak. (which adds calcium and magnesium) is going to the be pitcher for you. We’ve also heard good things about this BWT water pitcher, but unfortunately we were unable to test it this time.


Truckee & Reno


Water from Truckee and Reno has a higher mineral content than water from the Bay, so it needs to be softened slightly to produce the best flavors. Even though calcium and magnesium do help with extraction of flavor, if you have too much mineral content in your water, the resulting brew can turn out at best flat and at worst undrinkably chalky tasting.

This is why the Peak and the Brita came out on top in these markets. They both reduce hardness minerals, but don’t remove them completely. But the Peak’s remineralization technology boosted the flavor just enough to ultimately give it the edge for the top spot.


For Our Dark Roast Drinkers


Based on our experiment, you’re likely to get a perfectly tasty brew no matter how you filter your water! Overall, we found that water chemistry affects the flavor of dark roast brews less than it does those of medium to light roasts, but you can still tailor your filtration to suit your coffee drinking preference. If you prefer more of a smokey, earthy flavor, we recommend just removing chlorine and organics with a carbon technology such as the Hydros, which doesn’t mess with the mineral content of the water at all. For those who like their dark roast with a little less bite, we recommend softening the water using a filter like the Brita or Peak.


In Conclusion


What we found overall is that there is a bigger difference in water flavor from market to market than there is from filter to filter.


In other words, if we were to do this tasting again, we would be able to tell which market the water was from, not what filter it was passed through. Which just goes to show that there’s no one-size-fits-all solution for getting the best water to brew with at home.

This experiment was inspired by wanting to help create the best Coffeebar experience wherever you brew. If you’re a geek and are hankering for more information, please get in touch by emailing matt@coffeebar.com! And if there’s anything else our team should test around water, then please let us know.

Happy filtering!

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