Water is the key to good coffee
Posted by Matt Toogood on

Water is the key to good coffee

Water is often forgotten when we talk about coffee, which is crazy as it accounts for 99.5+% of the drink. Needless to say, water is key to getting the best out of a coffee. 

Going back 7 years ago we started to notice something changing, machines were starting to have faults that we had not seen before, the coffee was tasting "brighter" and in the wrong hands, sour and underdeveloped. Our suppliers in Italy helped us out with replacement components that had failed, carefully questioning us about water conditions without fuss BUT without prejudice, they started to ask if we could send the damaged parts to them. We started hearing the word "chloride". I remember the day vividly that I was shown a machine that was 3 months old with a microscopic hole in the boiler, the hole was so small that you couldn’t see the stream of water coming out until it hit you in the face.

What had happened is the Chloride, the ion that is negatively charged had started to reach the levels in our water supply that was silently starting to make huge impacts. Chloride ions love to eat metal, especially stainless steel, the metal that we believed was the staple of the food and beverage business because of its all resistant properties. We have had them in the UAE for as long as I’ve been here, it’s the reason we are all so used to having to replace our hot water heaters and it’s the telltale white deposit we all have in our homes. We just thought incorrectly this was calcium.

Chlorides are the SARs Covid 2 to stainless steel!


Salt water chemically has water (H2O) and salt (NaCl), plus a few other minerals in low concentration. In order to remove the salt, the most preferred method for mass removal is using Reverse Osmosis RO. Its works by passing water under pressure through an ultrafine membrane that allows only the H and the O through and stops all the Na and Cl and any other contaminants. The result is a super pure water. The challenge is that this super pure water is not great taste-wise for making drinks, in fact most people prefer some ‘flavour’ minerals.

In the Middle East we rely on desalination for all our municipality supplied water as the natural underground aquafers are long since depleted or are now ‘brackish’. The share volume of water being produced daily by the desalination plants is staggering. A golf course for example uses 1 million litres of water per day in the summer. A Saudi national told me once that if the supply of water to Riyadh, which comes directly from the ocean, was disrupted the city would be devastated in 3 days. We are used to seeing tanks that our municipality water is stored in at our homes and businesses, a legacy practice established in the days when consistent supply wasn’t available.

The desalination plants can produce water that is 100% pure, H2O with a pH value of 7.0 which is neutral, neither acidic or alkaline, however as seawater is normally slightly Alkaline at a pH of 8.0 and we usually see pH in this range or higher arriving at our homes and businesses. We measure any additional minerals (and contaminants) as Total Dissolved Solids (TDS) and this is measured in parts per million (ppm). Pure water has a TDS of zero. As its measured in ppm it generally is never absolute zero. A TDS water reading in a real-world situation will be 5 to 10ppm.

For our coffee business supplying and maintaining espresso and brewing equipment we had to find a solution to the problems we were facing with expensive coffee machines getting damaged in a very short space of time. We approached Culligans, Culligans is an international company with claims to be the world experts in water treatment. We contacted their team and had “engineers” visit and offer their Reverse Osmosis units. They asked what chemistry of water we wanted. We started with the guidelines from Italian manufacturers La Marzocco and Rocket Espresso. The proposed solution had a number of components and units costing over AED9,000 each, we sucked it up and purchased 2 units to test at our espresso bar while trying to work out how we were going to convince our customers that we now needed to recover from them an additional 25%+ cost for their coffee equipment and the ongoing maintenance annually of these units.

The reverse osmosis worked very well, the Chlorides that were causing the corrosion were removed.  We also discovered during the testing just how much large particle contamination was in the water. We had installed prefilters, these units are inexpensive, they are available in the supermarkets here. Prefilters remove contamination that is bigger than 5 Microns which is small, 0.005mm. We discovered that these filters were used up within a week, the main things that they filtered were sand and mud. Remember those tanks that you have, have a look inside!! (Side note in Dubai if you rent a property your Landlord is responsible for cleaning your tank annually).

The municipality desalination plants produce fresh water to a very high standard and at the plant the water is exactly chemically as they want it to be, the challenge is that the water has to get from the plant to the consumer via pipes that could be as old as Dubai, or brand new, a mixture of concrete, fiberglass and plastic are used at different stages and in most cases it arrives at a tank that may or may not have a lid that fits. We live in the desert, sand is a part of our life and the frantic pace of development means that municipality pipes are constantly being upgraded with roading and construction, and inevitably contamination occurs. We had large areas around the city that were under heavy development and needed prefilters changed twice a week. In fact, we had a customer that refused to put in prefilters and found within 2 weeks they had a 1cm level of sand in the bottom of the espresso machine boiler.


So we had a solution to the Chloride curse, Reverse Osmosis, which got us clean water and meant that the equipment was protected.  BUT the coffee tasted flat, boring and the flavours were hard to identify. The chemistry wasn’t right. What was missing was some good minerals. I like to use the analogy of sand paper, if the paper is too fine you can’t sand enough of the wood easily, too rough a sandpaper you gouge out the wood and take away parts that you want left behind. With coffee we need to make the solubles dissolve into the water. The water is the sandpaper, too fine and no yumminess comes out, too rough the yumminess brings undesirable flavours as well.

TDS total dissolved solids as I mentioned before is simply a measurement. The specialty coffee world worked out about 8 to 10 years ago that water of around 120ppm was a good ‘sandpaper’ but it’s a little more complex than that.  I actually still laugh because as in normal human nature, people new to the specialty coffee world, just as in any developing industry pick up on a concept without really understanding what it actually means and it becomes gospel. We were getting people coming into the shop and nearly yelling “What is your TDS???!!!!!!!!” before ordering a coffee. They knew the answer was what their friend, the ‘expert, in specialty coffee told them and they weren’t going to back down. Let me explain why this makes me laugh out loud and why the actual experts in our industry quickly coined the phrase “TDS, WTF”. TDS is measured in ppm, that ppm could be made of anything at all, any soluble and maybe that soluble may not taste so fantastic. Can I please have a coffee made with water of a TDS of 120 ppm of sewage… get my point?

Back to the challenge we had, now we had an expensive RO system, thanks to Culligans, but no TDS of anything. Culligans had a solution because their system has a small silver tap installed and the Culligans ‘engineers’ proudly lined up (yes there were 3 of them) and turned this tap a little, stood back and exclaimed, there you go 120ppm TDS. FACESLAP #1. The solution was to bypass the RO unit with the feed water, so they just added 100ppm of chlorides back into the water. I’m obviously not good at explaining concepts because I actually gave up with this engineering team and set to finding a different solution to the problem.

By now the good manufacturers of espresso equipment had gathered enough data that proved that chlorides were 100% of the problem. They had worked out that places that relied on desalination were at the top of the list of problems for the equipment. The Middle East, Perth, Capetown, New York. The so so manufacturers that got most of their business in Europe, where the water comes from the mountains and the ground not desalination continued to send every machine to these places with a water softener that must be installed to have a warranty FACESLAP #2, When you have water that comes out of the ground thru limestone which is Calcium Chloride (CaCl) this water has a high TDS, very rough sandpaper and this would coat up the equipment also not good. Water softeners are containers that you add …..SALT into to reduce the TDS… yep here we go again.

The lime got us thinking thou, how do we add a little of this? We believed that a little coating of the machines internals in calcium would be good, it would be like a protective barrier to the chlorides and would give us some of that needed TDS, calcium is also good for you if consume it in the correct amounts. We tried cartridges of calcium chloride and this indeed did work, sort of, the problem was we didn’t have a consistent flow of the water, so the TDS would bounce all over the place sometimes high, sometimes low. This is a disaster for a barista because his sandpaper keeps changing. You adjust the grind size of the coffee to be in balance with the water, so if the water has a lower TDS you will need to grind finer to make the surface area of the particle larger so its more soluble. This is why like most things, only about 5% of baristas make 95% of the best coffees, its science and skill.

In a commercial food and beverage operation you have a number of items of equipment that use water. Espresso machines, filter coffee machines, kettles, dishwashers, ice machines, hot water heaters and steam ovens. Not to mention water as an ingredient in cooking and baking. Here comes our not so friend Mr Chloride again. I remember because I actually was so concerned that I wrote an email to a CEO of a large F&B chain, asking for an acknowledgement that he understood that all of their equipment was at risk, unfortunately I was correct and after less than 2 years this business had to replace all their equipment in the bakery, espresso bars and kitchens, Millions of AED wasted.

This was happening all over the UAE and RAW was building a new facility, I knew we had to at least solve this problem for ourselves. I’m lucky, I have a business partner that allows my crazy in her world, so when I exclaimed that I was going to build a water treatment plant in the new place she just FACESLAPPED #3 and went back to roasting our amazing coffees. I approached water treatment companies that dealt in treating city water because I knew that these treatment systems could add and remove chemicals as needed. Things like chlorine and fluoride are added to water supplies all over the world and I just wanted to add some nice tasty and coffee machine friendly minerals to our water to get to the correct TDS. This turned out to be more difficult than I imagined. Firstly we needed 3000 to 5000L of water a day for absolutely everything in the building, for the equipment that mattered the most only 300L per day. These guys had the smallest system that made 10000L a minute. FACESLAP #4.

I got lucky and through a friend of a friend I found a company that got my crazy and were able to find small enough pieces of the puzzle that were able to make our treatment plant that we proudly now call RAWater. It produces up to 900L per hour of TDS120-130ppm water made up of the correct minerals that are perfect to make coffee taste fantastic and also protects all our equipment. We have a tap on the side of our building that we invite people to come and get their water for their home espresso machines from and now after 2 years of them doing this we have found that their equipment requires virtually zero maintenance apart from parts that wear out.


My next challenge was to workout a way that we could provide a solution to our commercial customers. They strangely didn’t have a business partner that would allow them to spend AED250K on a special project and most don’t have 30sqM to put in a treatment plant. So RAW water for coffee was developed…

Other than our RAW water, see our recommendation retail UAE water that is safe to use with your equipment:

















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