Gaggia Classic OPV Mod

RE*AC*TOR

So, after getting my La Peppina, I was struck with how much better the espresso tasted than my Classic. While I would still rate the classic better than 95% of espresso you can buy around Dublin, there were a few niggles.

1. Fines in cup. I know that a few fines (ground coffee) are unavoidable, but I was getting a more than I felt was acceptable.

2. I was getting lots of crema alright, but the coffee underneath seemed a little thin, not as thick or viscous as the Peppina.

3. Too hot. Even after running a blank shot the espresso was too hot to drink comfortably immediately.

I had a look here http://coffeesnobs.com.au/YaBB.pl?num=1175171794/0

and here http://coffeesnobs.com.au/YaBB.pl?num=1143118905/0


Basically Gaggia Classics often seem to be calibrated to a higher pressure than is required (or wanted). About 9 bar is optimum, but I found that mine was running at around 12 bar. So I followed the instructions above (requires a few tools and a blind filter basket for calibration) and set it to about 9bar.

The results - more crema (didn't think it was possible), fewer fines, thicker mouthfeel.

Still a bit hot though. I think I need to practice different flushing shots, to cool it down a little.

Mr Magnolia

Nice post RE*AC*TOR.

Am I correct in saying that you adjusted the setting of your OPV anti-clockwise ~ 1.5 turns or did you use the 270 degree adjustment? Did you carry out any further adjustment after this?

Do you know what flow rate you had before adjustment and what rate you have now? Should I have 100ml in 30 seconds on the return? (I want to make sure it's been set as per Gaggia before I start adjusting.)

Apologies if these questions are answered in the threads linked, I'm still reading



Any ideas why Gaggia don't employ these settings as their factory standard?

RE*AC*TOR

I made two 90 degree anti-clockwise turns until I got in or around 120mls in 30 secs. I was starting off around 70mls in 30 secs.

I measured the flow between adjustment.

You need to check what kind of pump you have. I have an Ulka E5.

Chance are you have the same, but you need to check as the rates will be different depending on the pumps.

This is the E5 graph
http://www.ulka.it/eng/img/inggraE/E5_3.gif

as you can see, my original flow rate of 70 in 30 secs, which is 140 in 1min equals about 12bar. 9bar is about 250 in 1 min - or approx 125 in 30 secs. I settled on 120 as it was close enough.

Mr Magnolia

Thanks. I'll have a look this evening, check my flow rates and try the adjustment then.

The graph looks borked?

RE*AC*TOR

Mr Magnolia wrote:

Thanks. I'll have a look this evening, check my flow rates and try the adjustment then.

The graph looks borked?

oopsie

http://www.ulka.it/eng/e5_gra.htm

Mr Magnolia

Opened it up there for a look. I have a Ulka EP5, which for all intentioned purposes seems the same as the Ulka E5.

Unfortunately, I don't have a blind filter basket. I thought I'd gotten one with the machine but it appears not. Therefore, I couldn't time the flow rate on the return. With this in mind I adjusted the OPV 180 degrees anti-clockwise. It will be easy to return the valve to it's original state from memory, should it have been necessary.

The result? As expected, velvet like smooth espresso, better than before it has to be said. It's now hard to tell the difference in texture between the crema and the coffee. Very thick crema lasting the whole way down. The crema residue is still in the bottom of the cup 5 minutes after finishing. TBH though, I can't tell if the fines were reduced. This may become evident over the coming days, it doesn't matter really though.

The flow on the pour went from 25 seconds to just over 30. I'll have to purchase a blind filter basket tomorrow and check the flow rates.

The flow on the pour went from 25 seconds to just over 30. I'll have to purchase a blind filter basket tomorrow and check the flow rates.


Great find RE*AC*TOR, thank-you.

RE*AC*TOR

Ok, well the 180 degree turn is probably conservative based on most people's estimates, and I think by and large they are over-pressure due to some coffee pod certification thing.

So you are probably in the ball park, but best to check and make sure.

Mr Magnolia

I'll check when I get the blind filter basket. Have you noticed a your coffee any sweeter/less bitter post mod?

RE*AC*TOR

I don't know if I'd necessarily say sweeter, but better overall flavour, and definetly thicker coffee.

Mr Magnolia

Sweeter mightn't be the best description but there is an improvement in flavour.

DaraghMAC

Hi,
I am having trouble with too much pressure from the pump. The water is flying through the filter and its kinda spraying all over the place apart from coming into cup!

I have opened up the unit and I can see that it is a Ulka E5 pump but reading your posts has left me with no clue as to how to adjust it or what tools I will need.

Could you post an idiots guide to reducing the pressure? This my first home espresso machine. I have only previously had a Nespresso machine. Pictures might help as there are so many moving parts I could be looking at the wrong ones!

PPC

DaraghMAC wrote: »

Hi,
I am having trouble with too much pressure from the pump. The water is flying through the filter and its kinda spraying all over the place apart from coming into cup!

I have opened up the unit and I can see that it is a Ulka E5 pump but reading your posts has left me with no clue as to how to adjust it or what tools I will need.

Could you post an idiots guide to reducing the pressure? This my first home espresso machine. I have only previously had a Nespresso machine. Pictures might help as there are so many moving parts I could be looking at the wrong ones!

Is it spraying all over when you have coffee in the portafilter?
If so you might want to look at grinding finer first.

Here's a video on lowering the pressure http://www.youtube.com/watch?v=xXoz6Aoykpg but again if you're not grinding fine enough its not going to help much.