This is the last(?) in my series on why I love HX machines.
Now that we know the basics of espresso machines it seems pretty clear that a double boiler is better than a heat exchanger, right? Not necessarily. This is an age old debate where neither side will ever be a winner. Yes, you can set the temperature of a double boiler digitally and the heat exchanger requires a cooling flush to obtain a desired temperature. This means that if you or your spouse wants to use the machine without understanding how it works that individual will have better success with the dual boiler because temperature will be set in advance and will not really be an issue.
There are, however, problems with that theory. The first is that if the person using the machine is inattentive enough that he or she cannot learn to control temperature on a heat exchanger then he or she almost certainly cannot master the much harder skills of dialing in a grinder, dosing and distributing the coffee, etc, etc.
Not only are those skills harder, I also think they have a far greater impact on the taste of the espresso. Change the temperature by a little bit and the coffee’s taste usually will not change dramatically, but change the dose or distribution by a bit and you can get a totally different taste.
The other issue is that I love playing around with my espresso, changing the variables on the fly. Sometimes I will pull four shots in a row at four temperatures to see the impact. This is easy to do on an HX, just adjust the flush by a few seconds here or there. It is harder on a dual boiler since you must change the PID and then wait for the boiler to catch up with the new setting.
Finally, on some dual boilers the steam boiler is smaller to either fit inside the case or to save on energy costs. In either event it can cause it to run out of steam.
In other words there are some major advantages to HX machines over DB machines. The end result leaves us without a clear winner. It will be a matter of personal taste. The tie breaker for me goes to the HX though because a given machine is almost always much cheaper as an HX than a DB and if the DB isn’t necessarily better the HX wins on price.
Half the espresso junkies on the planet agree with me (and the other half don’t).