How Water Can Make or Break Your Coffee

NotNeutral Vero Rose, Espresso Glass, Cortado, Cappuccino, Profitec Pro 500 PID, Espresso Machine, T64 Espresso Grinder Walnut,

There are seemingly endless techniques and tools for improving your coffee but people often overlook something that can make an astounding difference – water. While water itself is flavorless and colorless the water we drink comes with innumerable variations of minerals and PH balances. These variations can seem subtle but the impact they can have on the flavor of your coffee is substantial. 

So what is “good” water? That’s a tricky question and the answer depends a bit on what brew method you’re using, so let’s start with what makes for “bad” water.

First off, any water that has odor or color should be avoided. This may be incredibly obvious, but it’s an important first step. Luckily, for most this is scarcely an issue and if it is the solution is quite simple. Any fridge, faucet, or pitcher filter system should be sufficient to remove any extraneous odors or color from your water. So no we have a blank slate… or do we?

While we may have removed odor, flavor is a different story. If you’ve tasted one state’s tap water against another’s or prefer a specific brand of bottled water you’re familiar with this issue. The specific combination of dissolved minerals in water can result in a vastly different mouthfeel and flavor. In order to protect your equipment from scale buildup, you need to avoid particularly hard water. If you’re making pour over, a little scale buildup in your kettle isn’t going to hurt anyone. If you’re using a coffee maker or espresso machine, scale buildup can single-handedly ruin your machine. Further, really hard water just doesn’t make good tasting coffee.

What we want is filtered water with a relatively low dissolved mineral content. Even further, the specific dissolved minerals in that water will subtly change the way it tastes. Water with a TDS reading of 60 could have 60ppm of mostly dissolved sodium or mostly dissolved magnesium. Those two options will taste very different, and most water softening solutions add or subtract one of those two minerals from your water. Grab some water hardness test strips to check your water.

One of the most popular water softening options for espresso machines is in-tank water softening pouches. One of the longest-running brands is OSCAR, which makes affordable sodium ion exchange pouches. This pulls calcium and magnesium from the water and replaces it with sodium. In terms of softening water and protecting your machine from scale buildup, they work wonderfully, but sodium isn’t a popular choice when it comes to great-tasting espresso.

BWT, Oscar, Water Softening Pouch, Test Strip, Third Wave Water,

Most third wave coffee professionals prefer the taste of water that has a higher magnesium content. Luckily, BWT makes water softening pouches that pull sodium from water and replace it with magnesium. Their products are unique in this way and commercial versions of their products are used in many coffee shops. In terms of flavor, this is our pick for a water softening pouch.

If you plan to plumb in your espresso machine or want a softener you can hook up to your tap for use with a kettle or coffee maker, we suggest getting a water softening and filtration cartridge. We offer a kit that includes the cartridge, filter, stop valve, and pressure regulator – essentially everything between the machine or faucet and your water line. A single cartridge will last you around a year and ensure consistently filtered and softened water. Aside from being vital for direct plumbed espresso machines, it’s also the best “set and forget” option.

What if you want to have complete control over the mineral content of your water to ensure optimal taste and machine safety? The best way to accomplish that is to start with reverse osmosis or distilled water and add Third Wave Water. Each of these packets contains a precisely formulated combination of minerals for one gallon of water. Simply add the packet, shake, and give it some time to fully dissolve. If you already have a reverse osmosis system this is a no brainer and many dedicated home baristas prefer Third Wave for its flavor and consistency.

If you’ve already invested in nice coffee equipment the next step it's a no-brainer to invest in good water – not least because it’s the best insurance policy you can get for an espresso machine. Regardless of how you brew or what your plumbing may be, there’s a straightforward option to guarantee that your water is perfect for making delicious coffee.


  • I’ve been using RO water for well over a decade in some of my machines. Not all, since two are located in areas where the municipal water is below 70TDS and boiler safe. But two others are in 150TDS and +300TDS.

    In those high TDS area, the RO filter system (pump powered) reduces the TDS to near zero (single digits). The load is so light that I have been using the same membrane for ten years (I just change the physical prefilters).

    Since I drink only espresso-based coffee, the subtle “3rd wave” (or New Age :-) variations are less apparent to me. However, one simple approach would be to add a nice consistent bottled water (Volvic is low TDS) to a known quantity of RO water.

    I get a little peeved at those who claim RO water (or distilled) is somehow less healthy than “mineral water”. Which of course is a mixed bag of offerings from filtered municipal water to that from a “spring” that isn’t a spring (Poland Spring) and marketed by huge companies like Coca-Cola. As others have pointed out – they actually sell bottles – not water.

    The minerals in water are of little use to humans (almost all minerals are absorbed from food) and of course millions of people drink rain water with zero mineral content – and survive perfectly well

    SteveP on

  • I have RO that comes out of the main faucet (not the secondary slow flow faucets most people have). Is it possible to add minerals (or something like the water wave packets) to the RO water if I plum my espresso maker

    beth on

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