# Gaggia Classic Flow Control



## Gavin (Mar 30, 2014)

Hey,

Following someone's suggestion on here a while back, I've recently been experimenting with my portafilter mounted pressure gauge.

I've been opening the steam valve while the brew switch is on and noting the pressure drop at different points of the steam knob's turn. E.g 3 bar at quarter of a turn etc.

I've been using these reference points to do some preinfusion with some roasts I was having some difficulty with.

As I imagine the Bianca's paddle might work, although a bit more elegantly, I start the brew switch with the steam knob turned to my 2 bar marker, leaving it for a few seconds then slowly turning the knob until there's full pressure at the group.

It's a bit of a pain, and one wastes about 150ml of water out of the steam wand, but I've been impressed with the results so far. Visibly far less channeling/spritzing on those roasts and a better taste.

Just wanted to share and wonder if anyone else had any experience of trying this and what their results were?

Cheers


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## MartinB (May 8, 2011)

I think a common mod is to fit a dimmer switch to the water pump to control brew pressure, preinfusion, pressure profiling etc.


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## Gavin (Mar 30, 2014)

Ain't got the skills or know how for that. Also, I'd be so nervous about drilling the hole for the gauge.

Sent from my iPhone using Tapatalk


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## Hasi (Dec 27, 2017)

@Gavin

Ha, that sounds like a fun hack!

Flow profiling on a Classic, love it... 

@MartinB

Yea, a dimmer mod works for pressure profiling. It would only make sense in conjunction with adding a pressure gauge, so major (yet worthwhile) modifications there. Just a word of safety to anyone wanting to give these a go: working on 230V electrical components in a pressurised water-fed appliance bears quite some potential to be very dangerous. Make sure to use a dimmer that is meant to go in such an appliance, safety class wise.


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## Gavin (Mar 30, 2014)

Hasi said:


> Yea, a dimmer mod works for pressure profiling. It would only make sense in conjunction with adding a pressure gauge, so major (yet worthwhile) modifications there. Just a word of safety to anyone wanting to give these a go: working on 230V electrical components in a pressurised water-fed appliance bears quite some potential to be very dangerous. Make sure to use a dimmer that is meant to go in such an appliance, safety class wise.


 I know! Scary. Maybe I'll see if anyone can do this upgrade for me who's a bit more electrically competent


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## Hasi (Dec 27, 2017)

Gavin said:


> I know! Scary. Maybe I'll see if anyone can do this upgrade for me who's a bit more electrically competent


 think you'll find lots of folk wanting to mess with someone else's equipment  
Question is, are they authorised... because these days we quickly have liability issues if people get electrocuted or have their homes burned down. Welcome to the 21st Century ?


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## ArisP (Dec 17, 2019)

Hasi said:


> think you'll find lots of folk wanting to mess with someone else's equipment
> Question is, are they authorised... because these days we quickly have liability issues if people get electrocuted or have their homes burned down. Welcome to the 21st Century ?


 Is that bad? Isn't that why we have the Darwin Awards? ?


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