http://coffeeforums.co.uk/showthread.php?3859-Adjusting-the-OPV-%28over-Pressure-Valve%29-Gaggia-Classic

This works a beaut 😀

On start up my gauge hit the back of the zero stop of a 10 bar gauge.

The pressure is now at 9 bar and the espresso is smoother and sweeter than before ( after tweeking my grind )

Well worth 5 minutes effort

But I would recommend cleaning with Pury Caff and backflushing on a regular basis to

Care to hire out your pressure gauge? Have been meaning to try this mod for a while but having the gauge might spur me on 🙂

I keep meaning to do this!!

Rich I will post it to you just send it back when you have done, just send me your address on a facebook message

And you Alex

Cheers dude 🙂

do you think this will work with a Gaggia cubika?

I have a Classic. I have a grinder. I have settled on the beans I will be using for the foreseeable. Everything is working very nicely. Why would I want to do this mod? [Genuine Q by the way, not being a smartypantyarse]

Too much water pressure can force the water through the coffee grounds in the filter basket too fast thus under extracting the terpenoids and flavanoids that are in freshly ground coffee making it bitter and reducing the crema, to compensate for this you can use a finer grind and tamp harder thus making the puck more solid and slowing down the flow through it, the trouble with this method is you can have the grounds extracting for longer than is ideal and can lead to slightly burnt after taste.

The above mod cures this.

I may be wrong but that’s my interpretation of correct extraction with regard to water pressure vs grind

Coffee snobs rulez…… 😉

If you’re happy with the taste and setup then there’s no reason to make the modification to your Gaggia Classic.

It can do more harm than good if you alter the pressure too much in either direction.

A large majority are set right before they leave the factory. A growing number seem to need tweaking though as they are now set for pressurised filter baskets and not the standard ones many people change to.

Ah ok. Thanks.

I get a lovely crema. And my coffee tastes great. I go for a dark roast anyway. So I won’t be doing the mod.

I had to alter the pressure in my new Gaggia Baby machine i bought just before xmas with the PSA on here, it came with a pressurised basket with just one teeny pinhole in it and i swapped it for the basket out of my old Gaggia Baby Class, which as i had a new machine i felt it time to strip the boiler down and see why it wasn’t allowing water through the grouphead – turns out it was a teeny bit of gunge blocking the solenoid valve so i now have two working machines, perfect for the most addicted of espresso lovers!.

The pressure gauge is now doing the rounds does anyone else want to use it if so email me, all I ask is can you please post it on to the next person ( which is happening at the mo)or return it back to me

Email sent

Email sent

hhhmmm … meant to do this for sometime now but just haven’t got the time to buy a gauge … Will email you once I have some free time to mess around with my Classic.

the gauges are on the rounds Hammy and TNH you are on the list

its arrived! 🙂

Re Backflushing…

There is nothing in the Gaggia instructions about this. What is the purpose of backflushing and should I be doing this on my Classic?

Re backflushing
Section 8b

Ohhh interesting thread, ta.

email sent 🙂

tortoise not hair

Please can you re send me your address alas I deleted it so I can get the gague to you sometime

Ta SD

The gauge tour of the UK is still in progress if anyone else wants to use it drop me an email al it will cost you is the forwarding postage

SD

Hammy has done now and it is on its way to Tortuse not hair