Best water for coffee
If you’ve ever asked, “what is the best water for coffee?” You’re in the right place.
We’re on a mission to uncover what exactly is the best water for coffee. If you’re a lover of brewing coffee yourself, we encourage you to join us! Be warned – you might not look at tap water, bottled water or distilled water the same!
Water for coffee
If you’re a home coffee brewer, a barista or you work in the coffee industry then there’s a high chance you’ve already come across information on the best water for coffee. If you’re shaking your head, not to worry! After reading this blog, you’ll feel more than prepared. The next time someone mentions those three little words “reverse osmosis water” you’ll be able to give them all the details.
Researching water chemistry can open up a serious rabbit hole. Whilst some information can be convoluted and difficult to understand, other articles are simple and clear. In this article, we’re going to try to keep it as straightforward as possible. We’re not scientists by any means, but we certainly love coffee! And it’s this love for coffee that will drive the crux of this article.
We encourage you to refer to our references for more information (see at the end of the article).
Water for brewing coffee
Tap water, bottled water, purified water, distilled water…
There are so many types of water that it can be confusing!
Water accounts for approx. 98% of your morning cup of coffee (92% for espresso). You wouldn’t be able to make a coffee without it, so it makes sense we understand what’s in it, how it tastes, and whether it’s helping or hindering your coffee brewing.
For many everyday coffee drinkers, the impact of the water quality on your coffee taste might be new information. However, we bet you’ve already been taking note of the differences between good coffee water and bad coffee water.
For example, if you’ve always wondered why an espresso or a long black made at a cafe is always a better coffee than a cuppa made at home – there’s a high chance it’s because of the water filtration. If you’re using tap water for your home coffee brewing, it’s going to produce a wildly different taste than espresso machines, which commonly use a water filtration system. This water filtration can vary from BWT Bestmax cartridges or a reverse osmosis water system, which works wonders on the experience of your morning cuppa.
To put it simply, when you have the best water, you’ll have the best coffee.
And that is exactly why coffee nerds (like us!) have been researching water chemistry!
From the sky to your cup
So where does our tap water come from? We’re so used to having a quick and easy supply of tap water here in Australia that some of us might not consider where the water is sourced from.
Australia is one of the driest countries in the world. This means we commonly can’t rely on rainfall for our water needs. Therefore, most Australian tap water is sourced from channels such as streams, rivers and reservoirs or, recycling and desalination.
Water Corporation offers a feature on their website where you can type in your address and see where your home’s water is sourced from. For example, from our coffee roastery here in Bibra Lake, Perth, our tap water is a combination of water sources; desalination, ground, dams and replenishment.
Different water sources produce different mineral content, changing the taste of that glass of water and – a cup of coffee.
But, this then begs the question – which water will give the best coffee?
Third wave water
Although H2O appears clear and devoid of anything but, well, water! There are extra properties in the liquid to ensure your glass is clean and safe. This will depend on where your water is sourced from and what treatment process the H2O has gone through. For example, water sourced from a dam is going to be treated differently compared to groundwater.
After treatment, water is chloraminated (chlorine and ammonia). This stays in solution longer to deliver microbiologically safe portable water for your home use. Impurities are filtered out, the water is disinfected, and various other different minerals (such as fluoride) are added. Producing quite the mineral mix!
Worst water for coffee?
For those who are living in Perth (us included), there is some bad news…
Perth water contains 0.5 – 1.5ppm (parts per million) of chlorine.
Compared to Melbourne, which has around 0.3ppm – this is quite a big jump.
Although chlorine at this micro quantity is perfectly fine for human consumption, this addition gives tap water a distinct “chlorine-y” taste. Alongside this, the infamous chlorine taste is more prominent in warmer weather.
For Perth coffee drinkers, this is bad news if you’re brewing coffee in Summer. If you’re using tap water during those hot and steamy 40-degree days, that chlorine-y taste will be quite prominent. It’s no surprise Perth is renowned for having the worst water in Australia.
Often, people visiting Perth from Melbourne and Sydney can take note of the “chlorine-y” water straight away.
Best water for coffee
Here is where the fun begins.
Many have experimented with making their own water in search of the very best water recipe. See here for Barista Hustle’s DIY water recipe.
Ideally, you want water with a little chlorine. If you’ve accidentally swallowed water whilst attempting butterfly at your local swimming pool… you’ll understand why. Chlorine is unpleasant and will diminish coffee flavour if not filtered before making your coffee. This is because the chlorine reacts with the coffee and causes a bitter taste.
Fluoride can also alter the flavour of the water because it increases acidity levels. Acidic water can be bad for coffee extraction times. If water is too acidic, it can lead to a vinegary-tasting coffee. If water is only slightly acidic, pleasant acidity can really bring out the natural flavours in your coffee beans. It’s all about balance!
High levels of iron or copper increase water hardness. This can result in a metallic tang from those hard minerals.
Calcium and magnesium carbonates are hard minerals that cause water hardness. This can cause scale build-up in machinery. Calcium and magnesium are the most common mineral ions that can cause a mineral buildup. Although these dissolved minerals are the reason, your espresso machine needs regular servicing, they play an important role in your cup of coffee.
Tap water is stuffed full of all the minerals. Whilst some of the mineral content reacts with coffee brewing, different minerals are beneficial for extraction. You need a specific balance of these mineral ions. If you have no mineral ions, you’ll have very little extraction. If you have high mineral content, your coffee can lose its rich flavour.
Soft and hard water
Water hardness comes from contact with minerals rich in calcium, magnesium, and anything really the water passes through. As soon as the water hits the ground, the rain begins absorbing minerals.
Most of Australia is built on limestone bases, this allows for better water flow. However, it also dramatically increases the calcium naturally present in the limestone. This quickly leads to high mineral content in your water quality.
Hard water is also very problematic for espresso machines, as it causes limescale. Limescale is a concoction of calcium and magnesium found in hard water and particularly where water is evaporated.
Tap water (hard water) poured into a kettle is the ideal environment for scale build-up (not good) plus, the pressure of boiling water… plays a huge impact on scale. So, don’t say we didn’t warn you next time you inspect your kettle’s vessel.
Fun fact: obtain less scale in your kettle by scrubbing regularly with baking soda and using high-quality water.
Finding water balance
Ideally, we want the perfect balance of hard and soft water for the best flavours. Too hard (tap water in Perth), will cause unpleasant flavours in our coffee. If soft water (rainwater) our cuppa will taste muted as it’s unable to effectively extract the flavour of the coffee grounds. We’re looking for an in-between hard and soft water that’s just right (as Goldilocks would say).
Please note: a level of hardness is unavoidable for water as it’s impossible to remove all elements. This means the interior of your coffee machine will need to be descaled from time to time to reduce calcium buildup.
The Specialty Coffee Association has conducted ample research on the importance of water minerals. The Association explore the finer details of hard water, soft water, bottled water, soft tap water, too much salt water… and essentially any- and everything that relates to achieving quality water for your good cup of coffee. Definitely worth a read!
Another component to think about when it comes to water is alkalinity, which refers to the buffer capacity of a water body to neutralize acidity and maintain a stable pH level.
Ultimately, we want water to have a pH level of around 7 (pH scale is 0-14. Below 7 is termed acidic and above 7 is alkaline). If lower, the water can eat away at the inside of the coffee machine and mute coffee flavours. Higher results in alkaline. And, if there’s too much alkaline, it will result in an acidic and chalky-tasting cup of coffee. Generally, high alkalinity goes with higher hardness. Desalinated water has no hardness, i.e. calcium and magnesium, so the water authority raises the pH to take the aggressive edge out of the water.
Check our James Hoffman’s video on the water here.
Finding the middle ground is essential and will play a big part in doing your specialty Karvan coffee beans justice.
Total dissolved solids
Total dissolved solids (TDS) refer to the many organic and inorganic ions found in the water. For example – magnesium, sodium chloride, calcium and other substances.
Use parts per million (ppm) to record how much TDS is present in the water or coffee. For coffee, the goal is to have a TDS level of approximately 18-22%. However, this is wildly varying due to the different processes the coffee beans go through. Processing methods such as farming practices, washed vs. natural processing, roasting and the coffee brewing method all affect the TDS level.
Water we use for our coffee
Although it can be a fun process to create your own water truly, it’s quite a timely method. This is especially concerning if you own a café. In case you were considering it, we suggest not making your own water for a cafe.
The easiest, most effective and reliable solution is having a filtration system in the cafe. Some of the most common methods are Reverse Osmosis (RO) with magnesium remineralisation post-treatment or BWT Bestmax cartridges.
We use a Reverse Osmosis system at our Perth coffee roastery. RO is used for all of our coffees and teas. We use it for the water in our kettle, for cupping sessions, for making coffee and even for drinking water.
For home coffee lovers, we highly recommend treating yourself to Reverse Osmosis post-treatment and/or having good quality filtration at home. If you’ve ever read the taste notes present on your bag of coffee and have been confused about where in the world the coffee roaster got these taste notes from… this could be why. Water makes a dramatic difference to your espresso!
We understand investing in a RO system isn’t realistic for many who us a home espresso machine. Therefore, we recommend bringing in your empty bottles and we’ll fill them up with RO water you can take home! Pick up your beans and pick up your RO water! Your brewing process will never be the same again.
Alternatively, you can try bottled water for your water for brewing coffee. Bottled water (depending on the brand you choose)
Special thanks: A big thank you to Glyn from BWT for making sure the RO water at our roastery is the best in the buiz!
Want to learn more? Check out these resources for more info on the water for coffee.