A friend tried my espresso made with profiling (30 sec blooming + 6 bar turbo with a one-step decline to 4 bar when 2/3 of the weight poured out) and was shocked, haha!

He has a Breville Bambino and I told him about the dimmer mod. However, I have a question:

Can a dimmer be installed on an espresso machine with a thermoblock or thermocoil?

With them, the heating temperature depends on the flow rate (slow flow - the water heats up more, fast flow - the water heats up less since it doesn't have enough time). If you significantly slow down the water, won't it heat up too much? And wouldn't stopping the pump completely for the 30 seconds blooming cause the device a damage (or even be dangerous)?

There are videos on YouTube of dimmer being installed on such machines, for example:


Still, my question seems legitimate.

By the way, the same goes for installing a dimmer or FCD on a heat exchanger machine. It won't break, but still, won't the water be hot as hell at the end of a "manual lever shot"?

Sure, it can be installed, and yes, the temperature of the water in the thermoblock will climb as flow is reduced; that is how a thermoblock can be used for steaming - the pump is pulsed for very short periods for very low flow. However, the great thing about water is its maximum temperature once it hits the puck is 100C (at sea level, etc.) and thermoblock groups are notoriously cold, so ...

As for damage, the dimmer mod won't be dangerous/cause damage - the brew thermostat should turn the element off - and there is a safety thermostat.

BTW, watch Lance's recent review of the Bambino for more info on how to get the best out of that machine.

baldheadracing wrote:As for damage, the dimmer mod won't be dangerous/cause damage - the brew thermostat should turn the element off - and there is a safety thermostat.

When the blooming ends and the dimmer switches the pump back on, does the heating resume? That is, does the heating element react to the suddenly appearing flow of water, or does the fool-proofing electronics switch it off completely and the brewing has to be restarted by clicking the brew button?

In 30 minutes of blooming, the element has time to cool down a little. If the heating automatically resumes, won't all the water pass before the element heats up again? Especially with the short turbo shot. Thermocoil heating is fast, but still not instantaneous.

I hope there are people on this forum who have installed a dimmer on a machine with thermocoil, and can share their impressions.

Depends on the design of the particular machine.