The speaker performed a "power switch mod" to disable the Eco Mode's 15-minute automatic shutoff, allowing for extended testing. They also mention testing inexpensive springs from AliExpress to replace the OPV spring and measure the resulting pressure, and they plan to detail these and other mods in future videos.
This video reviews the Gaggia Classic E24 espresso machine, focusing on the reasons behind its high quality and improved features compared to previous models. The speaker conducts several tests and shares data to support their claims regarding temperature stability and other improvements.
Pre-2014 Gaggia Classic models used an aluminum boiler and a brass group head, along with a solenoid valve, an adjustable brass OPV, and rocker switches. The E24 uses a brass boiler and group head, eliminating the issues caused by the different metals. Later models (post-2014) experimented with stainless steel and aluminum boilers with Teflon coatings before returning to the brass boiler in the E24. The rocker switches and adjustable brass OPV were replaced with push buttons and a less durable, non-adjustable plastic OPV in some intermediate models, issues addressed in the E24's design (though the plastic OPV remains).
The speaker compared the temperature stability of their Gaggia Classic E24 to their 2006 Gaggia Classic model. Using a thermocouple type K and consistent brewing parameters (19g in, 40g out in 25 seconds), they measured the temperature in the puck at different points in the brewing cycle. The E24 showed significantly less temperature variation: a mere 1.5°C difference between maximum and minimum when brewing at the "light off" point (97.2°C initial to 97.6°C peak), compared to larger variations in the older machine using either PID or the standard thermostat. The E24 also showed minimal fluctuation (3.1°C difference) when brewing at peak temperature (118°C boiler temperature), and 3.7°C when brewing at the "light on" point. The older machine showed 4.3°C and 5°C variations with PID and thermostat, respectively. The E24's temperature stability was described as "amazing" and "super stable," even exceeding the performance of their Rancilio Silvia with PID.
The "boiler gate" refers to a period where Gaggia introduced a new aluminum boiler coated with a Teflon-like material to prevent scaling and galvanic corrosion. However, this coating began to flake off, requiring Gaggia to replace many machines and boilers. This negatively impacted Gaggia's reputation, leading them to switch back to a fully aluminum boiler with coating and, eventually, to the all-brass boiler found in the E24.
