Barista Magazine

APR-MAY 2018

Serving People Serving Coffee Since 2005

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Page 119 of 135

A L e a g u e o f T h e i r O w n 120 barista magazine cannot precisely control the temperature of the brew water. You simply don't achieve the same temperature stability that most coffee professionals want. In our work, we're showcasing coffees that have been meticulously grown, sourced, and roasted up until the point of preparation, so having temperature-stable brew water is the last piece of this much larger puzzle of obtaining that perfect shot of espresso. To achieve this temperature stability, you add more boilers and thicker boilers. Thicker boilers have more thermal mass that will keep the temperature of the water more stable, but the metal also needs to stay heated. More mass has been added that needs to be kept hot at all times. Fundamentally, to achieve higher performance in espresso machines, you're trying to keep more water hot and available at a set temperature at all times. More boilers means water isn't being drawn from the reserves of any other boiler, thereby causing less temperature fluctuation as new, cold water from the water line enters the boiler. On many specialty machines, each grouphead has its own boiler so that the stability of the water dispensed on the espresso grounds is as consistent as possible. This is the path to high performance, but it's not necessarily the path to high efficiency. (To be fair, heat exchangers can be used in multiboiler systems as well, but fundamentally they are used to "preheat" the water coming into a brewboiler so that the temperature remains more stable. It's not meant for efficiency as much as it is for performance.) This technology allows us to provide a consistently high-level product to our customers, but more water needs to be heated at all times than with other espresso machines. With the quality standards of our industry, however, multiboiler systems are the new baseline of what is required to provide a consistently high-quality coffee beverage. Some machines now even utilize a preboiler to heat the water before it goes into the steam and brew boilers to further add to this temperature stability. Again, this is more water being kept heated more of the time. In this same vein, there are even machines that reheat steam to reduce water vapor and provide better steaming performance. More heat, higher performance, but more energy. Energy efficiency and high performance are not necessarily mutually exclusive. We want to keep more water hot than ever before, and there are new tools that the industry is just now tapping into to achieve better heat retention without having to use more energy. What has truly been a game-changing innovation in the field is the introduction of vacuum-insulated tanks. These tanks preserve temperatures in the tank much better than any other current method. They are being pioneered by Marco in its MIX series of hot-water systems. The technology is essentially a vacuum-insulated travel mug. As many of us know from experience, coffee simply stays hot all day long in a vacuum-insulated travel mug and no added energy is required. Transferring this technology to hot-water towers means less energy needs to be used to maintain the temperature of the water at its set temperature—again, that's the temperature of the water that you are trying to maintain within the tank at all times. This increase in energy efficiency also means that you can do more with less. A smaller tank can provide more hot water more quickly at a more stable temperature while also taking up less space and leaking less heat into the café itself, requiring less cooling of the space. That's a win-win. It seems likely that this technology will be further developed and

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