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Most espresso machine manufacturers have short-listed one goal to the very top of their list: provide you with the proper environment to pull the best shot possible. Like the perfect storm, the right conditions hinge upon having the ideal pressure and temperature. For espresso enthusiasts, finding the perfect formula for each shot involves ongoing trial and error. A major point of interest and case study, of sorts, in the coffee community involves a technique called “temperature surfing.”
Temperature surfing can be performed a number of ways, but its ultimate aim is to get the best brewing temperature out of the group head. While most semi-automatic machines are equipped with thermostats to help regulate water temps, the thermostats focus on controlling boiler temperature. As some coffee lovers have noted, there is always a variation sometimes minor, other times noticeable, between the boiler and brew group temperature. Also, some machines may brew too hot and others too cold for your liking. Temperature surfing can help you get closer to your target brewing temp.
While it’s a matter of personal preference, and you can definitely make great-tasting espresso without using this method, the theory behind temperature surfing relies on generally accepted coffee logic. If brew temps are too cold, you’ll end up with a sour, lackluster shot. If they’re too hot, your espresso is likely to be bitter. Also, optimal brewing temperatures may vary for different roasts and blends. You may find that a light roast tastes just right at one temperature but a dark roast may require a slightly different brewing environment to extract the perfect shot.
According to our resident tech experts, temperature surfing is completely safe when done properly and will not negatively affect your espresso machine. Under normal circumstances, it won’t affect your warranty either. If you plan to try temperature surfing, though, be sure that your machine has plenty of water to prevent a dry boil—which has the potential to damage the unit.
Keep in mind that temperature surfing is normally done for single-boiler and heat-exchange machines. It’s not necessary for units with double boilers, like the Gaggia Baby Twin, since these machines are particularly adept at temperature control.
Again, we defer to the tech department; but this time there isn’t a clear consensus of opinion. It basically boils down to this: Temperature surfing will add additional time to your brewing routine and it isn’t an exact science. Even if you choose to temperature surf, you still won’t have complete control. Let the steam run too long on a single boiler machine and you risk brewing too hot. On the other hand, with a heat exchanger, if you run too much water through your group head you may be brewing too cold.
Our advice is…let your taste buds be your guide. If your espresso tastes its best after you’ve temperature surfed your machine, great! If you like the espresso your machine makes as is, without temperature surfing, more power to you! This is a part of the art of espresso; it’s fun, experimental and sometimes oh so subjective.
Some Semi-Automatic Espresso Machines may have the tendency to brew a tad too cold for your liking. This may be the case if the maximum temperature of the machine’s thermostat is on the lower side. Even if the machine is in the perfect temperature range, if you want to brew a bit hotter, you can do so by “tricking” the unit into thinking it is about to steam instead of extract.
Since these machines use the same boiler to brew and steam, there will be a natural temperature variation between the two functions. For extracting espresso, the boiler temp for most machines is lower than it would be if you were to steam or froth milk. Thus, you can trick the machine into raising its boiler (and ultimately brewing) temperature, by activating the steam function as soon as the brew-ready indicator light comes on. The longer you leave the steam function running, the hotter the machine temperature will be. Once you’re ready to brew, turn the steam function off and extract your espresso right away, before the boiler has a chance to cool down.
Heat exchange machines—with the exception of dual-boiler units like the Expobar Brewtus models and the Pasquini Livietta T2—could brew slightly too hot for some users. The reason for this is because the water you’re brewing may have been heating in the boiler for an extended period of time if the machine has been left on. The water, which will work its way through the group head when you extract a shot of espresso, may be near boiler temperature—over 212?F and too hot for brewing purposes.
In order to avoid extracting your shot with water that’s too hot, simply remove your portafilter and run water through the brew group. If the water that’s flowing through machine is too hot, you’ll see fine wisps of steam emanating from the group head. Continue to let water flow through the unit until the steam disappears, this will be your indication that you’ve purged all the overheated water from your machine. Make sure you have your portafilter filled, tamped and waiting on the side. To brew, simply reattach the portafilter and follow through with your normal routine.