Calibrated Water

The air felt buoyant, free from the typical suffocating humidity. It was a refreshing, lung-affirmed sensation that awakened me to my surroundings. The birds were a little louder too, possibly due to the local macaw’s piercing voice sounding through the trees in greeting. It was almost as if my senses were amplified on stepping off the bus after the five-hour journey that had taken us into the heart of Honduras, to the beautiful town of Copán Ruinas—close one of the most important sites of the Maya civilization. Overlooked by nearby mountains and etched with winding cobblestone streets, this was to be home for the next four days, and, what was more, I was there to attend an event called Let’s Talk Coffee, where I was to be surrounded by coffee conversations and smiles. I could not have been happier.

We at Third Wave Water cosponsored the event, and so on arriving on day one, I was curious to see where our water mineral packets had landed. I made my way through the Speakers Hall (where I caught our friends Jon Allen and Andrea Allen from Onyx Coffee Lab sharing their story on stage) towards the Cupping Room to (ahem) test the waters, as it were.

To my surprise, I discovered that our mineral packets had made it as far as the first hall, where local roasters were brewing and showcasing their coffees, but not to the Cupping Room itself, where they were using distilled water. After speaking with a few of the personnel, it was clear that they were not going to mineralize this water. I was confused. Why would they use distilled water in the Cupping Room? The question remained on my mind throughout and after the next few days of conversations, presentations, cuppings, and connections and, energized from it all, I was eager to explore the question a little nearer.

We know different types of water can create drastically different results when brewing or cupping coffee. In 2017, during our appearance on ABC’s Shark Tank, my co-founder Taylor Minor and I showcased a side-by-side comparison of coffee brewed with our mineralized water versus local Los Angeles tap water, prepared by champion barista Dylan Siemens, who was with Onyx Coffee Lab at the time. After tasting, Barbara Corcoran remarked, ‘This coffee tasted twice as good as the other cup, and everyone responded the same way.’ It was clear that the tap water was inferior to the mineralized water, how would it have done against distilled water? At the event, we learnt that distilled water creates a consistent water profile that facilitates clear communication; when coffee is transported across continents, discussing tasting notes can be challenging without a common language. If a seller in country A describes a coffee as having hints of jasmine, a buyer in country B can more easily validate those notes and make a purchase. However, if different types of water are used for cupping in each location, the tasting notes can vary dramatically. To address this with a quick fix, the specialty coffee industry adopted distilled water, since it is easy to produce worldwide. Inexpensive distillers typically cost less than $100 and effectively remove chemicals, minerals, and harmful organics.

Speak the same language

Using the same water for cupping makes sense for consistency, but I was still bugged by the use of distilled water, as it is widely recognized in the specialty coffee community for dulling flavours. Pete Licata, in his book How to Get the Best from Your Coffee, explains that, ‘When it comes to what’s in our water, we know we need a small amount of dissolved mineral solids—without them, our brews are off-balance and unpredictable.’ Similarly, Christopher Hendon, in Water for Coffee, explains, ‘It is often (correctly) cited that you need some mineral content in brewing water, which is why distilled or deionized waters do not produce great cups of coffee.’

If distilled water works for standardizing language, but leads to poorer-tasting coffee, could coffee farmers receive lower scores—and consequently lower prices—for their coffee?

What is Calibrated Water?

The Specialty Coffee Association (SCA) water standard, established in 2001 and updated in 2018 in the SCA Water Quality Handbook, provides comprehensive requirements to help coffee taste its best. We define Calibrated Water as water that is easy to replicate and meets the SCA water standard parameters. This Calibrated Water is shared with all participants in the supply chain to facilitate consistent communication and optimize coffee flavour.

The specialty coffee industry is already familiar with calibration, as Q-graders must retest every three years to maintain their certification. During my time at NASA in Houston, TX, we used calibrated equipment for consistency (and safety). It’s no different with coffee; calibrated water is essential for achieving consistent flavours.

To determine if Calibrated Water yields better scores than distilled water, we formed two teams to cup and score four coffees using these two water profiles. Team one was led by our Q-grader Andrea Costa, while team two was led by Juan Welchez, a Honduran coffee farmer with a wall of qualifications, including but not limited to an MBA and a Master’s in Agronomy and Crop Science.

Juan’s team included Raul Moreno, a lead cupper at the Cup of Excellence-winning farm La Salsa in Honduras, and Carlos Rene Guerra, a two-time Honduran barista champion and owner-operator of Café San Rafael in Copan Ruínas. Andrea’s team included Ana Mallozzi, a Q Grader from green coffee importers Covoya Coffee, and Britta Gustafson, Director of Training at New Harvest Coffee in Rhode Island.

The four coffees ranged from lower-scoring 80-point coffees to higher-scoring 88-point coffees to assess a variety of quality levels. Both teams followed SCA cupping protocols, comparing distilled water to a Calibrated Water profile meeting SCA water standards and based on Third Wave Water’s Medium Roast water profile.

The results

Andrea’s team scored the cups using Calibrated Water an average of 0.625 points higher, while Juan’s team averaged 1.187 points higher.

At first glance, these numbers may not seem significant, but Juan pointed out that even a single point increase can raise the price per pound by a few cents. ‘This may seem trivial,’ he said, ‘but for us farmers, every single cent matters, especially in Honduras, where most coffee falls within the 80–83-point range.’ A one-point jump can also be crucial; elevating a coffee from 79 to 80 points means that it crosses the threshold into specialty coffee and commands a much higher price. We also consulted Benjamin Carlson from Long Miles Coffee in Burundi, who shared a similar perspective: ‘We have seen a minimum of one point and up to three points higher cupping scores between regular water and Calibrated Water.’ He also noted that some waters actually negatively impact cupping scores, which is why his team observed such a variance. Factors like excessive alkalinity or local contaminants can adversely affect coffee quality. For more information on alkalinity and its effects, see Scott Rao’s article in Standart issue 25.

What now?

Using distilled water suppresses flavour and results in lower cupping scores. For coffee farmers, whose livelihoods depend on these evaluations, the stakes are high. A low cupping score can undervalue beans, preventing farmers from realizing the full worth of their harvest.

While calibration may seem dull, it is essential for supporting the farmers who grow our coffee. To genuinely assist them, we must seek to unify the coffee industry on this point, and embrace the tools available for effective coffee cupping, like Calibrated Water.