# How does the machine work?



## barrykensett (Dec 15, 2009)

I always find it easier to use a machine propoerly if I know how it works, perhaps that is the engineer in me. Is there a reference somewhere I can read up how the Gaggia Baby Dose works? The sort of things I don't understand is what happens when I have made the coffee and press the steam switch, Presumambly the boiler is still full of weaterat this point and it heats to a higher temperature to make steam. I get the impression that the steam can run out (maybe I leave it on too long) but I don't understand why the pump does not kick in to keep the boiler full. If I want to make another brew I have been going back to the startup boiler fill routine but I am not sure whether I need to do this, the instructions say that I only have to do it when I first switch on but I suspect that when I have steamed the milk that the boiler is not full ready for the next brew?

I also had a brief flirtation with a Baby Twin (which broke down after six days of use and is still waiting resolution) which supposedly has two boilers but I can't see how that setup works either but with that one the pump did kick in while I was steaming. I need a step by step technical description of how the machines work because for the life of me I can't work it out.

Apart from all this I am getting predictably good coffee every time so I must have learnt something!

Barry


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## DonRJ (Apr 3, 2010)

The Gaggia baby as you have noticed does not autofill the boiler when steaming so it has a finite amount of water to use for the purpose. mine will steam for around 3 mins max then the steam dies off. So I have dveloped a routine of not steaming more milk than I can heat in two and a half minutes, then switch back out of steaming mode and press the non timed brew button (with the portafilter off), the pump runs, steam blasts out of the group head for a few seconds followed by water. Once I have a steady flow of water I switch the pump off, the boiler is now refilled ready for another steaming session if required or brew another shot because the process will have cooled the boiler down again.

The Baby Twin uses a seperate "thermoblock" to steam, this needs a steady supply of water to flash heat into steam hence the pump running I guess. Its not a boiler in the true sense and you can see pics here of boiler bits.

http://www.coffeeco.com.au/articles/july2002.html

More expensive machines, eg HX types will autofill there boilers having a sensor in the boiler which triggers the pump, the Gaggias lack such refinements

Essentially the Gaggia only knows when to run the pump when you press the brew or hot water buttons.


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