The Gaggia Classic is a very nice machine.  I own a similar machine call the Gaggia Coffee which looks a lot like the Classic and shares a majority of parts with it's more expensive sibling. One feature found on the Classic is an adjustable over pressure valve.  When the water coming from the pump passing through the OPV before heading into the boiler exceeds a set amount of pressure, a pea valve held tight by a spring is pushed up creating a path for the water to flow into - one the pressure is lowered the spring overcomes the water pressure and the pea drops down to block the opening which closes the valve.  By compressing or decompressing the spring inside the valve the pressure can be adjusted.

Why is this important? Gaggia machines are shipped adjusted to 11 bar from the factory to accommodate ESE pod standards.  Pods are very popular in Europe so being certified as a good pod brewing espresso machine is important to the manufacturer.  Non ESE pod espresso - ground coffee espresso - tastes better at 9 bar of pressure than it does at 11 bar.  The grind can be coarser, the doses can be smaller, and the extraction is correct as well.  Better tasting espresso is what it is all about and this simple tweak gives this to the Gaggia.  Can you make a shot with out performing this adjustment? Sure you can, it is just harder to get a great shot since the margin for error is small at 11 bar compared to 9 bar.

How do you make the adjustment? Unplug the machine. Remove two screws from plastic on top toward the back. Remove the top cover.  Locate OPV - it will be a brass tube attached to the bottom of the boiler with a line coming in from the pump and another line coming out of the top that runs down into the water tank. Take off the tube from the top of the brass OPV, then remove the threaded cap with a 17mm or adjustable wrench.  A little water will be sitting underneath - this is normal.  Take a 5mm Allen wrench and turn counter clock wise 240 degrees (not quite 3/4 of a round). Replace 17mm cap. replace water line to OPV. If everything is tight you shouldn't have any leaks. Replace cover and screws. Plug in, let it heat up, and pull the best shot the Gaggia Classic can make.

Some Deep Cello Black Tie Blend before I go.

 

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Comments

Submitted by wakeknot on
I think this could really help Gaggia owners. I wonder if this is why I've never thought the ones I've had coffee off of measured up - they were set wrong for good espresso?

Submitted by EricBNC on
<br>The Black Tie is very good as an espresso shot. I like what I taste coming out of Deep Cello.

Submitted by EricBNC on
<br>I was surprised too that the improvement in shot quality was so dramatic. Having the adjustable OPV on the Silvano made a believer out of me when it comes to pressure.

Submitted by EricBNC on
<br>lol - buying the parts to build a portafilter pressure gauge would be simpler - having one (attached to another machine) laying around made the task simple. I understand how some machines might not need to be adjusted to exactly the same pressure as my friend's Gaggia Classic but this gets someone in the ballpark. Once someone sees how easy the tweak really is, adjusting for taste should be a breeze.

Submitted by jslive (not verified) on
I noticed a massive improvement in shot consistency after the OPV adjustment. Much more balanced taste and less sour and bitter notes. I ended up doing a full 360 degree turn which might have been a little too much but im happy nonetheless. Prior to the OPV mod I struggled between grinds that either choked the machine or delivered blond gushers. That was using the Gaggia MDF. With perfect grind, distribution, and tamp that the OPV mod is unnecessary. However, for us mortals a correctly set machine makes life easier.

Submitted by EricBNC on
<br>I agree the improvement is dramatic - glad to hear your espresso has improved too.

Submitted by yeahyeah on
I saw a marked improvement after adjusting my Gaggia's OPV as well.

Submitted by EricBNC on
<br>It is like night and day if the unit is way out of adjustment fresh out of the box - I recommend it highly.

Submitted by EricBNC on
<br>Gaggia's are nice - the Classic has a few parts that are different but yes, they are more similar than different.

Gaggia Classic Feeling the Pressure?

| by

The Gaggia Classic is a very nice machine.  I own a similar machine call the Gaggia Coffee which looks a lot like the Classic and shares a majority of parts with it's more expensive sibling. One feature found on the Classic is an adjustable over pressure valve.  When the water coming from the pump passing through the OPV before heading into the boiler exceeds a set amount of pressure, a pea valve held tight by a spring is pushed up creating a path for the water to flow into - one the pressure is lowered the spring overcomes the water pressure and the pea drops down to block the opening which closes the valve.  By compressing or decompressing the spring inside the valve the pressure can be adjusted.

Why is this important? Gaggia machines are shipped adjusted to 11 bar from the factory to accommodate ESE pod standards.  Pods are very popular in Europe so being certified as a good pod brewing espresso machine is important to the manufacturer.  Non ESE pod espresso - ground coffee espresso - tastes better at 9 bar of pressure than it does at 11 bar.  The grind can be coarser, the doses can be smaller, and the extraction is correct as well.  Better tasting espresso is what it is all about and this simple tweak gives this to the Gaggia.  Can you make a shot with out performing this adjustment? Sure you can, it is just harder to get a great shot since the margin for error is small at 11 bar compared to 9 bar.

How do you make the adjustment? Unplug the machine. Remove two screws from plastic on top toward the back. Remove the top cover.  Locate OPV - it will be a brass tube attached to the bottom of the boiler with a line coming in from the pump and another line coming out of the top that runs down into the water tank. Take off the tube from the top of the brass OPV, then remove the threaded cap with a 17mm or adjustable wrench.  A little water will be sitting underneath - this is normal.  Take a 5mm Allen wrench and turn counter clock wise 240 degrees (not quite 3/4 of a round). Replace 17mm cap. replace water line to OPV. If everything is tight you shouldn't have any leaks. Replace cover and screws. Plug in, let it heat up, and pull the best shot the Gaggia Classic can make.

Some Deep Cello Black Tie Blend before I go.

 

Category: BLOG

Agreed

December 11, 2011 | by EricBNC


Gaggia's are nice - the Classic has a few parts that are different but yes, they are more similar than different.

Gaggia makes a lot of nice

December 4, 2011 | by intrepid510

Gaggia makes a lot of nice machines, I really like my Classic and they really are all about the same except a few parts.

@yeahyeah

November 29, 2011 | by EricBNC


It is like night and day if the unit is way out of adjustment fresh out of the box - I recommend it highly.

OPV

November 14, 2011 | by yeahyeah

I saw a marked improvement after adjusting my Gaggia's OPV as well.

Welcome jslive

October 31, 2011 | by EricBNC


I agree the improvement is dramatic - glad to hear your espresso has improved too.

I noticed a massive

October 30, 2011 | by jslive

I noticed a massive improvement in shot consistency after the OPV adjustment. Much more balanced taste and less sour and bitter notes. I ended up doing a full 360 degree turn which might have been a little too much but im happy nonetheless. Prior to the OPV mod I struggled between grinds that either choked the machine or delivered blond gushers. That was using the Gaggia MDF. With perfect grind, distribution, and tamp that the OPV mod is unnecessary. However, for us mortals a correctly set machine makes life easier.

@jbviau

October 12, 2011 | by EricBNC


lol - buying the parts to build a portafilter pressure gauge would be simpler - having one (attached to another machine) laying around made the task simple. I understand how some machines might not need to be adjusted to exactly the same pressure as my friend's Gaggia Classic but this gets someone in the ballpark. Once someone sees how easy the tweak really is, adjusting for taste should be a breeze.

You are hereby formally invited...

October 12, 2011 | by jbviau

...to come up to Baltimore and adjust mine! Of course, you'll need to bring the Silvano also to compare with.

@wakenot

October 12, 2011 | by EricBNC


I was surprised too that the improvement in shot quality was so dramatic. Having the adjustable OPV on the Silvano made a believer out of me when it comes to pressure.

@broseph

October 11, 2011 | by EricBNC


The Black Tie is very good as an espresso shot. I like what I taste coming out of Deep Cello.

great tip

October 11, 2011 | by wakeknot

I think this could really help Gaggia owners. I wonder if this is why I've never thought the ones I've had coffee off of measured up - they were set wrong for good espresso?

how was black tie as 'spro?

October 11, 2011 | by donnedonne

how was black tie as 'spro?

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