Apr 02, 2020

New Technologies for Specialty Cafes Improve Water Quality

This article originally appeared in Water Quality Products Commercial Water Spring issue as "Wake Up & Smell the Coffee"

coffee, water quality

Water systems for cafes are going through some major updates and specialty coffee is to thank. The specialty coffee industry grows more than 9% every year, which is forcing the supporting vendors to feel the pressure to improve their products. Thankfully, innovation is not new to this niche industry, creating new espresso machines like the Slayer Steam promising better steamed milk, the specialized coffee grinder by Fellows reaching more than $1 million on their Kickstarter this month, an electric coffee roaster by Bellwether and now a patent-pending water system like the Tethys by Third Wave Water. 

What Is The Perfect Water to Brew Coffee?

There are many coffee industry related groups helping guide these innovations, including the World of Coffee (WOC), the International Coffee & Tea Festival and Coffee Fest, but one of the largest is the Specialty Coffee Association (SCA). The SCA organized the science to define a water profile required to brew great coffee. They also operate the Coffee Roasters Guild and the Coffee Technicians Guild, whose goal is to help technicians in specialty coffee. What does the perfect water to brew coffee look like? It is defined as the following (with acceptable ranges in parenthesis): 

  • Chlorine = 0 mg/L
  • TDS (total dissolvable solids) = 150 (75 - 250 mg/L)
  • Calcium hardness = 4 grains, 68 mg/L  (1-5 grains or 17 mg/L - 85 mg/L)
  • Total alkalinity = 40 mg/L (At or near 40 mg/L)
  • Sodium = 10 mg/L (At or near 10 mg/L)
  • pH = 7 (6.5 - 7.5)

The negative effect of using poorly treated water on coffee and cafe equipment cannot be understated. The water used to brew your coffee can cause unnecessary scale for your coffee equipment and ruin your coffee as detailed in SCA’s Water Quality Handbook and Maxwell Colonna-Dashwood and Christopher Hendon’s book, Water for Coffee. Getting a great water profile at home was Third Wave Water’s first mission with their mineral packets, but now they are trying to help cafes with Tethys. The SCA water profile was primarily created for effective coffee brewing, not necessarily to coffee equipment’s operating requirements, but the Third Wave Water engineers wanted to finally provide both: an equipment-safe, SCA water profile for the cafe ecosystem, effectively keeping up with the specialty coffee’s growing requirements. 

Not All Coffee Is The Same

Tethys currently utilizes two water profiles: the Classic Profile and the Espresso Profile. The Espresso Profile was engineered for espresso machines and can be used with all coffee brewing equipment while the Classic Profile was designed for everything else: batch brewers, pour over bars, kettles, etc. Both water profiles use magnesium and calcium citrate as the base while they differ with their third ingredients. The Espresso Profile uses potassium bicarbonate for an added buffer for espresso machines to protect the boiler, while the Classic Profile uses sodium chloride. The Langelier Saturation Index (LSI) demonstrates that the higher the temperature and pressure, the more propensity for corrosive effects from the water to metal surfaces. The system allows the operator to vary the TDS from 50 to 250 TDS, which changes the total hardness and the buffer as desired to highlight flavor notes in different types of coffee.

While providing the SCA water profile was the initial requirement for the team, they also wanted it to be a 250 gallon a day, all-in-one water system for an easy installation. This effectively created the dimensions of a small fridge with the following sub-systems: a high efficiency reverse osmosis (RO) water filter system, two specialized atmospheric water tanks for mixing and storage of the treated water, a patent-pending powder dosing system, a 2-gallon accumulator, a custom controller and built-in manual bypass valves. The system operates on 110 VAC, has a footprint of 25 by 30 inches while standing 65 inches tall and uses a 3-inch touch screen for operation.

The Tethys system stands 65 inches tall and uses a 3-inch touch screen for operation.
The Tethys system stands 65 inches tall and uses a 3-inch touch screen for operation.

Using atmospheric tanks creates a higher efficiency for the RO water filtration system, which is close to a 2:1 water-to-waste ratio. And since the water system uses atmospheric tanks, ultraviolet (UV) filters were added to destroy bacteria. To reduce power drain, UV-C LED filters by Aquisense were chosen because they can be turned on and off only when water is flowing through the lines. This avoids the constant drain of electricity in comparison to the typical UV water disinfection lamp that requires constant voltage for effective use. 

Two of the engineers on the Tethys team have extensive experience working for NASA and Virgin Galactic and are familiar with aerospace reliability requirements. One aerospace requirement utilized was predictive maintenance (pDM) as defined in the Reliability Centered Maintenance (RCM) approach. The engineers added various sensors throughout the system to monitor pressures and TDS levels using an internet connection for automatic generated reports to add these pDM capabilities. Keeping the system operating with as little down time as possible is a key focus of RCM by adding pDM to track wearable items in order to replace them before they fail. Also creating an effective maintenance program with preventative maintenance (PM) tasks helps to replace key items and identify failures before they become problematic. Corrective maintenance (CM) with the ability to easily replace Line Replaceable Units (LRU) or components that typically fail during operation is also essential. 

Sustainable RO

In an ever-growing eco-conscious industry, some have asked Third Wave Water about the use of RO systems and their impact on the environment. 

“Water is a renewable resource, which is unlike the burning of a natural resource that converts to energy and is lost forever,” said Third Wave Water CEO Taylor Minor. “For every 100 gallons of waste water created by our RO system, it is an equivalent carbon footprint of running a 100 watt lightbulb for 4 hours.” 

The water drained by RO systems is not lost forever, but the energy used to perform the pumping operation can be monitored by wattage or energy used. While reducing waste is a good goal for every organization, reducing the right type of waste is more effective in the long term. Thankfully, water is a renewable resource so RO systems do not have to be a hindrance for future water supplies.

The system was designed to be a water quality talking point amongst baristas and customers.
The system was designed to be a water quality talking point amongst baristas and customers.

“We were sick of the water systems always being found in the back of the cafe,” Minor said regarding the design of the system. “We wanted a design that felt natural to present to your customers.” 

The water systems are a missed opportunity to highlight equipment being used by a cafe. Having a water system where your customers can see it can provide a new talking point for the baristas to share how they are helping coffee at their cafe taste its best. 

About the author

Charles Nick is president for Third Wave Water. Nick can be reached at [email protected].

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