What is the Best Water for Coffee?


There is an entire world out there that exists for the sole purpose of finding the perfect coffee bean and roasting methods. Coffee connoisseurs everywhere know what is at stake when you do not have the right bean or the right roasting process, but what about the right water? 

What is the best water for coffee? You want to brew your coffee with water that has a hardness level of 50-80ppm and a pH level between 7-8.5. Water that is too hard will take away from the flavor of your coffee and cause calcium to build up in your machine. pH levels that are too high can also suck flavor straight from your coffee.

Seeing as water nearly makes up 99% of the physical components of your coffee, there are some general guidelines that will help to maximize the smoothness, richness, and overall flavor of your favorite cup of joe. If you are someone who wants to make sure every component of your coffee is exactly right, continue reading to know if you can brew coffee with distilled water or purified water and the science behind what great water does for coffee.

What is Distilled Water?

First, let’s take a good look at what distilled water really is. Because water is a resource produced by nature, it is chock full of different minerals. These minerals include the “good guys” like calcium, magnesium, and potassium. However, mother nature did not just give us the good in water, she gave us a little bad as well. 

Minerals that are the “bad guys” would be those such as led, arsenic, and aluminum. Because of these “not so great” minerals existing within water, many have taken on the task of extracting them in order to present a more purified water. Distilled water, however, goes even one step further than this. 

So, what is distilled water? The goal of distilled water is to completely rid pure H2O from any sort of contaminants such as those “bad guys” listed about, like led, arsenic, and aluminum. However, this process also takes away all of the “good guy” minerals as well.

The process of distilling water is relatively simple. Distilled water is made through boiling regular, unaltered water at very high levels. The extreme boil is necessary because many of those bad minerals have high boiling points and need extra time under the heat in order to be completely dissolved. During the boiling process, steam is produced and collected in a separate storage container from the original boiling area. 

Once the steam has been collected, there will be enough combined together that it returns back into a liquid. This liquid is then cooled and produced for selling: your distilled water. The result is  water that is completely without any sort of harmful mineral, but it has also been boiled so long and at such high temperatures that it no longer contains any beneficial mineral. Around 99% of those good minerals are boiled off, leaving your water rather empty. 

Can You Brew Coffee With Distilled Water? 

Water purity is something that has become somewhat of an empire. All around the globe, manufacturers have found ways to take a naturally regenerating element and bottle it into an item that is sold by the billions of gallons. Even more, water purity has joined the conversation and lots of talk surrounds the question of how pure your water should be before drinking. For coffee, some may believe distilled water to be a good brewing option, but is it really?

In order to complement the flavors of your coffee beans, you want water that contains some minerals and has a bit of pH in order to cause a harmonious reaction that will leave your mouth singing not wanting for something more. 

So, can you brew coffee with distilled water? Because of this need for minerals (more on that later) you want to avoid distilled water when brewing. Distilled water can be a great option for other types of uses, but when it comes to your coffee mate, it is generally best left alone. 

Many times, people find themselves brewing in beautiful espresso machines, ornate french presses, or coffee store owners have invested in various coffee machines that would cost an arm and a leg to replace. 

Because of this, they want to protect those investments and ensure that they will have a very long life of use. To make this happen, some may think distilled water for brewing is a great option because it will keep any sort of mineral build-up from occurring. Although this line of thought is good in theory, it is flawed in a few ways. 

Why Shouldn’t You Brew Coffee with Distilled Water?

While attempting to use your best coffee machines, it is understandable that you would want to run only the best water through them. However, distilled water is not the right answer here.

So, why shouldn’t you brew coffee with distilled water? First, distilled water will attempt to take minerals (ions) from various components of your machine. Then, your machine will consequently run poorly. Next, distilled water is not the best choice for the best-tasting coffee due to the minimal mineral content.

First, let’s think about the machine itself. Many pieces of equipment are chock full of different minerals as they are made from materials such as stainless steel, copper, brass, and nickel. When you constantly run distilled water through these materials, the distilled water, which is drained of minerals, will begin to try and take ions from those different pieces of your machine. 

Once this happens, although there is no mineral build-up, the water will begin to breakdown the materials it is constantly exposed to and it will result in poor performance of your machine after some time. A fool-proof plan to protect your investment can actually result in damage, just a different sort from the type you were looking to avoid. Your coffee brewing machine is one that needs to be protected, but that will not occur through the use of distilled water. 

Second, let’s talk about something even more important: the coffee itself. There should be a mineral balance in your coffee to help produce a smoother cup. This relies on water that has a good level of hardness and lower pH level to allow for the right amount of available space for the coffee to make its way into. If your water has too low of mineral content, too much space is then available for the coffee to permeate and the result of your brew is typically very bitter. 

If your water has too high of mineral content, there will not be enough space for your coffee to make its way into and your coffee will typically taste sour as the robust flavors were not able to fully make their way in. This is why distilled water is not your best bet. There are not enough minerals to give your coffee just the right amount of space to reach its full flavor potential. As it turns out, all water is not created equally when it comes to java making. 

Can You Brew Coffee With Purified Water? 

Now, not to be confused, distilled water is a type of purified water. However, distilled water is often seen as being in a category all of its own due to the extreme purification processes that take place in order to ensure there is no trace of any harmful components when used. Purified water is something you are going to find around every corner and within most homes. This is the water that is bottled and the water consumed through different at-home filtration systems. 

So, can you brew coffee with purified water? Purified water is a much better option for brewing coffee because there are still some minerals present within it after its purification process. In general, purified water is removed of different contaminants such as bacteria, chemicals, and toxins that are unsafe for consumption. 

For purified waters such as bottled water, once purified, minerals are added back into the water in order to have a product that resembles that of a healthy natural mineral water.  Typically, tap water has been purified to a degree in order to meet health code standards. 

However, in some areas, this process is not enough and further purification needs to be made in order to make the tap water drinkable. If you live in an area like this, simply get a home purification system and use this water to brew your coffee. This system will also help to filter out chlorine, which is typically used for public water but tends to bitter the flavor of your coffee. 

Since purified water contains some minerals unlike distilled water, it is a great option for brewing coffee. Due to this mineral content, your coffee will have enough room when brewed to permeate the water without being too restricted by overhard or too soft tap water. Luckily, if you don’t have access to great tap water, many options are available to you to help purify and get that bad boy working in action with your beans and coffee maker for a great morning cup. 

What Components are Important in the Water Used to Brew Coffee? 

Not all water will do when it comes to making a great cup of coffee. It may seem that water is generally pretty standard across the board, but this is not so. As with many things, there is a science behind the construct of water and how it affects the taste of your morning, afternoon, or evening cup of joe. 

There are three general areas that need to be adhered to in order to make the best cup of coffee: 

  1. Hardness
  2. pH Level 
  3. Total Dissolved Solids 

Let’s take a closer look.

Hardness 

We hear it all the time, the talk of hard and soft water, but what exactly does this mean? Hardness refers to the magnesium and calcium content in water. Hard water is full of these, but soft water, on the other end of the spectrum, has none. If you have ever been in an area with hard water, many times you can see the white calcium build-up that sometimes occurs on showerheads or faucets. This would be very hard water, but you see my point. 

For coffee, the right level of hardness is needed in order to come out with a perfect flavor rather than one that is too bitter or sour. For the best flavor and smoothness, you want your hardness levels to be around 50-80 parts per million. Parts per million is the mass of any chemical per unit volume of water and you want this level to be just right when heading for your “start brewing button” on your beloved espresso machine. 

If your water is too soft, there will not be enough magnesium or calcium content in your water and this can lead to a very disappointing cup. For water that is too hard, you can easily use filtration systems. For water that is too soft, there are water hardeners available that will help get you to your desired level of hardness. If you don’t want to fool with either, finding a purified water that has the right amount of minerals could be your best bet. 

pH Level 

With your water’s hardness, you do not want it to be too hard or too soft, but just right. There is a middle ground needed to achieve a good brew when it comes to coffee and in the same way, pH is just important. pH is a measure of the hydrogen ion concentration of water and is ranked on a scale of 1.0 to 14.0. pH is thus the indicator of acidity or alkalinity – fun words to say, but what do they mean, and why they are needed to get a great taste for your coffee? 

Acidity 

The lower the pH level of water, the more acidic it is going to be. If the pH level is high, then your water will be more basic, which is what is referred to when using the term “alkaline.” for the best cup of coffee and even for your own drinking water, you want the pH level to remain around 7-8.5. If the levels fall below seven, the acid content can get to be so large that it begins to have a corrosive quality to it. 

For your water, this could mean that it could contain things such as iron, copper, lead, and even zinc – lots of metal contaminants that are not good for your coffee or your body either. If your water has levels below seven, you can typically tell through its taste. It will usually have a taste that is somewhat like baking soda and even the texture of the water will be different. Rather than being mostly unclinging to the touch, it will feel rather slippery. 

Alkalinity 

On the opposite end of the spectrum from water that is too acidic, there is alkalinity. Alkalinity refers to water’s ability to neutralize acids. Alkaline compounds help to lower the acidity of water through their combination with H+ ions to create new compounds. If the alkaline levels are too high in your water, this can result in a very bitter taste for your coffee. Between the acidity and alkalinity, you want them both to be at a relatively neutral level. 

If the pH levels are too high or too low, it can leave the water you plan to use for coffee in a bit of a bad place. Make sure the water you plan to use is one that meets a pH level in that general area of 7-8.5 to avoid having a coffee that is either too acidic or too bitter. These levels are also better for consumption and will thus keep your water and you happy and healthy! 

Total Dissolved Solids 

What are total dissolved solids? I am so glad you asked. Total dissolved solids, or TDS, is exactly as it says. It is the total of all dissolved things in your water, every single bit of it. Many times in the coffee world, people refer to the TDS level in water and claim that it affects the flavor of their coffee. However, as it turns out, this level has relatively no effect when it comes to the outcome of taste for your brews. 

The point here is that although you need to adhere to the hardness of your water as well as the pH levels within it to get a better-tasting coffee, the amount of total dissolved solids is mostly irrelevant. Most water that is available to the general public will have levels that are totally suitable for maximum flavor. This means that you can forego the worry of TDS and head straight to brewing. 

Final Thoughts 

Water is going to vary from town to town, state to state, and country to country. Water is not something that has a general makeup across the board and because of this, there are some factors to consider when it comes to its effects on the flavor of your coffee. What is important here though is that generally, there are not a ton of waters you need to avoid when it comes to mixing it with your coffee beans.  

The one water you really need to stay away from is distilled water. Outside of this, obviously avoid water that has not been purified or does not reach general health standards for consumption. You want your water to be well balanced with enough minerals to get your coffee looking and tasting like its best self. Know the science behind your water and get to sipping!

Tim S.

Tim loves roasting, brewing, and experimenting with coffee. After years of perfecting this craft, working as a barista, and owning a small coffee service in college, he has decided to share his knowledge with the world.

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