I own a Profitec Pro 700, plumbed in with a regulator, and it makes great espresso. I have been working with pre infusion and my espressos are even better now. I have taken a good look inside the machine and been thinking since then: this nice rotary pump motor can probably be looped through a rheostat to enable us to vary its speed. Would that enable us to vary the pressure of the pump? If we play with the rheostat during infusion, could we do pressure profiling that way?
If there are any electrical engineers out there, what do you think of this?
Thanks

Hi, have you checked this video? hope this help.
https://mecoffee.nl/

Interesting; I'll check it out, but it doesn't seem to be quite the same thing.
Thanks !

Not convinced that adding variables to the process is a good idea.

Think of the effort we go to to get our grind, dosing and brewing temperatures consistent. Introducing avoidable variability into the brewing process doesn't make sense.

It makes heaps of sense once you've mastered consistency and added variables improves the result...

Sounds like a great way to void the warranty.

aecletec wrote:It makes heaps of sense once you've mastered consistency and added variables improves the result...

I wouldn't say the added variables of pressure profiles necessarily improves the results. Absolutely changes the results, which can be a change for the better or worse depending on the coffee and the particular pressure profile. That said in my opinion and experience some coffees can definitely be pulled better with a particular pressure profile than typical straight to 9 bar then off.

In some ways I think the pressure profiling learning curve is as bad or worse than all the rest that came before learning to pull consistently good to great espresso AND is a prerequisite needed with a goodly degree of mastery before embarking on pressure profiling. Adding the seemingly infinite possibilities of pressure profiling only makes sense when it makes sense in your Journey.

Issue I see is that you may have to disconnect the pump from gicar or you can risk blowing the gicar depending on how it is wired, if voltages are being manipulated, etc. You want to find out if the pump is connected to a separate solid state relay, i.e. signal wires go from gicar to the separate relay to the pump. If it is then you can simply bridge the pump side of the relay and autofill will work as needed. I'm thinkin this is most likely case with a big rotary pump, but if the relay is on the board itself, then at the very least I would try to find someone who has connected a secondary power to pump also connected to gicar controller without issue or there is a risk you may need to buy a new gicar.