Why is it important to find an Aus Spec coffee machine?
Italian Spec coffee machines are factory set to deliver brew water near 96 deg C to suit dark roast Coffee Robusta beans. Aus Spec coffee machines are set near 93 deg C to suit brighter, lighter and fruiter Coffee Arabica beans.
With single boiler or dual boiler machines this isn’t a problem as temperature can be controlled directly using a digital controller (PID).
When it comes to heat exchanger coffee machines it is a completely different story. With Italian E61 heat exchanger machines at factory settings the water in the E61 group superheats to well over 100 deg C when the machine sits idle. This means that a cooling flush is needed before pulling a shot. A cooling flush isn’t just an extra step. The need for a cooling flush means that the thermal stability of these machines is terrible. Of course, thermal stability is critical to consistently brilliant espresso.
In Italy where they use dark roasted Coffee Robusta beans and enjoy bitter sweet espresso this seems to do the job. In Australia most of our beans are Coffee Arabica, the fruitier and brighter coffee bean varietal. Our roasts are also lighter. As mentioned above, the ideal brew temperature for these beans is around 93 deg C.
If you are looking for an Italian heat exchanger coffee machine make sure that you find one that has been factory modified to deliver brew water near 93 deg C. The modification isn't as simple as just reducing the boiler pressure. The theromosyphon also needs to be modified as well to keep the brew temperature stable. These machines are referred to as Aus Spec.
Before committing to an HX Italian espresso machine ask your retailer if the machine is Aus Spec. If the retailer doesn't know what this means then let the warning bells ring. The second question to ask is "what brew temperature is the machine set to?" Again, the retailer should know.