TL;DR: Use filtered (not distilled) water with a pH between 7-8.5 for the best coffee. If you find your coffee is a bit “chalky,” use a water softener to reduce the pH slightly — but try to stay above 7.

Coffee brewing is a simple thing: a marriage of heat, water, beans, and (in the case of espresso), pressure — that’s it. And as with all simple things in life, the quality of your ingredients becomes more and more important with the fewer you have. As such, ensuring that you use high-quality beans and the proper water is crucial to a high-quality cuppa coffee.

This is something that I’ve learned through years in professional kitchens and coffee shops (along with a touch of trial and error), but not everyone should have to struggle to learn what I have. With that said, let’s talk about water: why it’s likely more important to your coffee than you think, what makes “good” or “bad” water, and how to make the most of what you have available.

What’s in My Water?

This is a difficult question to explain without a bit of background, for to most people, water is water … right?

Well, yes and no. The basics of the water you drink remain mostly the same — hydrogen and oxygen combined into the near-tasteless requirement for most life on Earth. However, in the past several decades, “designer bottled water” has become a common sight. You know the names; Fiji, Smart Water, PATH, VOSS, and the like have claimed that their water is different from that peasant tap water. But is it really?

The simple reality is that, ultimately, water is mostly the same — the difference lies in additives (or the lack thereof). Tap water in most cities generally contains added minerals, chemicals, and even medicine. The most common things in tap water, especially in larger cities, include:

• Chlorine: This is used to sterilize water in water treatment facilities, as it’s incredibly common for municipal tap water to sit for days, weeks, or even months before it’s used. To prevent bacterial growth, most cities add a (minimal) dose of chlorine to keep it clean.
• Fluoride: Fluoride in water has garnered a bit of attention, both good and bad, in the past two decades. It’s intended to help tooth health, but it’s absolutely not intended to be consumed in large amounts.
• Lead: Whether you like it or not (probably not), lead pipes are a reality for most older buildings. This goes for cities, too, meaning most tap water inevitably has some trace amounts of lead.
• Nitrates and herbicides: Nitrates occur naturally in most soil, and herbicides are used for commercial farms. Unfortunately, this means that each can, and will, leech into the water source from runoff.
• Mercury: Like lead, mercury can occur naturally, but it’s also used commonly in factories and refineries and found in landfills. While this isn’t a guarantee, homes near industrial and agricultural areas may have trace amounts of mercury in their water supply.
• Methyl tertiary butyl ether (MBTE): MBTE is commonly found in gasoline. It’s used to limit carbon emissions, but this means that it can easily be found anywhere that gas is used or stored: along roads, in storage tanks, and especially in areas contaminated by spills. While uncommon, MBTE can make its way through runoff into local water supplies.
• Perchlorate: Like MBTE, perchlorate is commonly used in fuels and industrial settings. Also like MBTE, it’s not common to find perchlorate in your water — though it has been found in several states’ water supplies.
• Prescribed or illicit medication: We all know the trope of flushing meds; while we won’t discuss that here, it is a reality of sharing water with people in a city. It is entirely possible to find various medications (in trace amounts) in your water.

With that said, filtration tends to remove most of these additives — hence the growing trend of using a household water filter pitcher or sink attachment like Braun or Brita. Most “designer” water brands tend to boast specific pH levels in tandem with a distillation, filtration, or reverse osmosis process to remove the majority of these additives, though the difference concerning coffee can be minimal.

What Type of Water is Best for Coffee?

The simple answer is that when making coffee, you want to cut as many additives from the equation as possible. Because of this, you generally want:

• Filtered (not distilled) water
  • Filtration removes many minerals and chemicals from your water, ensuring you’re only putting water in your coffee. On the other hand, distilled water tends to remove all of the minerals from your water, which is bad for your coffee flavor.
  • Reverse osmosis water is also generally not going to achieve what you want, so stick to simple filtered water. (It suffers from the same issues as distilled; it’s extremely lacking in minerals.)
• Slightly alkaline water
  • Believe it or not, water has a pH balance. Keeping your water between 7-8.5 pH tends to allow you to extract more flavor while balancing coffee’s acidic nature. In other words, aim for the more alkaline side of a neutral pH.

It’s also worth noting that water varies from place to place.

For example, readers from the UK are likely used to their area’s hard water. In contrast, people in the American and Canadian Pacific Northwest (my homeland) and the South Atlantic Gulf tend to have far softer water.

Water whose total hardness is too high (AKA highly alkaline, generally above 9 on the pH scale) can produce an almost chalk-like flavor and texture in coffee, whereas incredibly soft water (acidic and low on the pH scale) tends to bring less flavor from the same amount of coffee.

What to Consider When Choosing Water for Coffee

While we’ve covered the basics of picking the best water for your coffee, there is (surprisingly) more to discuss. While you don’t need a chemistry degree to pick water, I generally recommend that those who want the best out of their coffee ask the following:

Is It Safe to Use Tap Water for Coffee?

Generally, yes. With that said, though, keep the information we covered above in mind. For example, if you move and notice a stark contrast in the quality of your coffee, consider testing your water. Water testing kits are cheap and easy to use, and they can allow you to figure out what may be wrong. Maybe the water in your new home is just a bit more acidic or alkaline than you’re used to, or maybe there are additional minerals (or chemicals) in your new tap water.

If you test the water and find that there are any of the chemicals listed above in your water, buy a water filter and use filtered water — you’ll likely notice a difference almost immediately.

(Side note: If you find that your water needs to be filtered, be sure to clean your coffee/espresso machine thoroughly first. If the minerals are already inside your coffee machine, filtered water will only solve half of the problem.)

How Effective Are Coffee Filters at Filtering Water?

Truthfully, coffee filters are ineffective at best at truly filtering water. They’ll catch larger bits of minerals that you may be able to see with your naked eye (after all, they’re meant to filter finely ground coffee beans), but they won’t remove nitrates, fluoride, or any other chemicals that may be in the water.

Should I Use Distilled Water for Coffee?

As mentioned above, distilled water tends to remove all of the minerals from your water. While this can be good for some specific uses, it’s generally more harmful to the flavor of your coffee than helpful. Coffee needs minerals to properly extract, so you’ll do a disservice to yourself and your beans by using distilled water. Plus, distilled water is generally more expensive — so stick to filtered.

What if I’m Camping or Away From Power?

If you don’t have access to a filter, especially if camping, there are some options for you to still get high-quality coffee from what’s available. First off, I highly recommend using an Aeropress or French press, as they’re meant to be used without power. Coincidentally, there are water filters like this one that are built for this exact problem — no power needed.

How to Get Around a Water Filter

If you really, really don’t want to get a filter (or just can’t), there are some options. Finding a high-quality electric kettle (also see this one) can help to remove some impurities by simply boiling the water — something that your coffee machine and its paper filter absolutely can’t do.

Ultimately, using a water filter is always going to be your best bet, but that’s also just not always realistic.

What to Look for in Water for Coffee

As you can tell, picking water for coffee isn’t as simple as “that’ll do.” More often than not, it can take a bit of trial and error to find the perfect balance for you, and it can vary depending on where you live.

Because of this, there’s no one “right answer.” Rather, I want to offer some general advice.

Alkalinity vs. Acidity

For those unfamiliar with the pH scale, here’s a quick rundown:

• The pH scale runs from 0-14, with most common foods running somewhere in the middle. Cleaning agents, like bleach, can reach the high (or in this case, low) end of the scale, but you generally don’t want to see a pH of under 3 or above 9 in your water — and that’s a generous gap.
• Alkaline water generally falls above 7 on the pH scale, tending to taper off around 8.5-9. Once it reaches those levels, a water filtration system or modification of the water is advised. A common home trick is to use one tablespoon (15mL) of vinegar per one gallon (3.8 L) of alkaline water.
• Acidic water generally falls below 7 on the pH scale, though we tend to want our water to not be acidic at all. This is where specific fixes come into play, such as bicarbonate, calcite, limestone, or magnesia as additives to balance the water’s acidity.

Mineral Content

Humans need the minerals that are commonly found in water (as well as most foods) to survive, plain as that. Coincidentally, coffee requires some minerals, such as:

• Magnesium
• Manganese
• Chromium
• Cobalt
• Potassium
• Silicone
• Calcium

While the lack of these minerals won’t necessarily ruin your coffee, an overabundance of them certainly will. This is why testing (and filtering) your water is generally considered the best practice for coffee.

Odor and Color

These factors are more common sense than they are science magic.

If your water smells — or looks — off, don’t use it. Discoloration is a sign of high mineral content, and sometimes rusting pipes, whereas a smell means something other than water has made its way into your tap.

Find the Best Water for You

Ultimately, water can be far more complicated than we’d like, and the addition of coffee to the equation can make things even more confusing. With that said, though, sticking to a few key rules can allow you to remain healthy and make some tasty coffee in the process. Aim for water between 7-8.5 on the pH scale (as recommended by the Specialty Coffee Association), and use filtered (not distilled) water for the best results.

Now, go make a cup of coffee and enjoy knowing that you’re just a bit more well informed. And if you find that you still have questions, don’t hesitate to reach out to one of our Curated Coffee Experts. We’re here to help, and (believe it or not) we quite enjoy talking about the finer details of coffee — including water.