blog from the ceo & superbarista of phoenix coffee, home of the best baristas in cleveland, ohio

Tuesday, January 10, 2006

Heat exchange technology as applied to espresso machines

Yesterday, while speaking with a representative for an espresso machine manufacturer, I learned about heat exchange technology. This is a term I have heard more than once, but did not necessarily know what it described. Well, in layman's terms, here goes...

All commercial espresso machines have a boiler that contains hot water. When the hot water is used by the machine to brew espresso, cold water, through the supply line, must be brought into the tank. Maintaining a constant temperature in the boiler is a desireable state, as this constant temperature would result in more consistent brewing temperatures. So instead of having the cold water enter the boiler directly, in machines that have "heat exchange" technology (which I'm guessing many or most machines do now) the cold water lines first go through the middle of the boiler, being heated by conduction, and then empty out into the boiler itself, after the water has been somewhat heated. In so doing, warm water is emptied into the boiler directly, rather than cold water.

Elegantly simple. Now I get it and can use the term "heat transfer" somewhat intelligently.


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