Whether you should get a dual boiler or a heat exchanger coffee machine is a common question. Ultimately, what you choose comes down to your individual style of coffee consumption and purpose.
If you predominately brew black coffee at home the choice is simple as there are two machines, both heat exchangers, which we recommended specifically for the brewing of black coffee – Elektra Micro Casa and the Bugnetti Simona. If you prefer your coffee with milk however, it is important to understand the difference between heat exchanger and dual boiler machines to make the choice that’s right for you.
A boiler is a cylinder made from stainless steel, copper, brass or aluminum which stores, heats and maintains water at a set temperature, which will then be pumped out to your brew head. As you might gather from their name, dual boilers consist of two boilers combined in a single machine, though each serve different function. One set a lower temperature will be a brew boiler, while the other will be set a much higher temperature and be a steam boiler. Using two separate boilers allows you to have complete control of the temperature of the brew boiler, and will be much more consistent in extraction. Both dual boilers and heat exchangers don’t need to multitask having to rely on just one boiler, giving them flexibility to brew and steam at the same time, which means less time wasted temperature surfing waiting for them to balance out. However, dual boiler machines are quite large given the need to house two boilers inside. Secondly given their superior output and greater number of parts dual boilers are much more expensive machines and can cost anywhere from $4,000 to $25,000, and is this suitable for true coffee enthusiasts or café owners.
A heat exchanger coffee machine however has just one boiler which will be set at a steam temperature, but it features a small heat exchanger rod which passes through it to differentiate the steam and extraction water temperatures. When the extraction occurs, fresh water will be pumped through, being heated as it passes through the heat exchanger rod. As the water used to brew the coffee spends quite little time in the machine this prevents the water flavour being tainted by the metal in the machine. Heat exchange machines also tend to be smaller than dual boilers, which is suitable for those who value their kitchen bench space. However due to the method heat exchange machines use to heat brewing liquid they can experience a greater fluctuation in temperature than one would encounter using a dual boiler. Heat exchange machines range from $2,000 to $4,000 in price, and are perfect for the beginner home barista.
Dual boilers represent the best of the best, but are more suitable to those with large budgets and the kitchen bench space to house their large size, while heat exchangers are more suitable for the home baristas who want to make a great brew while more sensitive regarding price and space.