Posted Tue Feb 27, 2007, 6:04pm Subject: Re: Gaggia pressure problem and subsequent fix
I can set for stagnation (blind) or dynamic pressure, simulating a shot., or pulling a real shot & measuring exact extraction brew pressure. Stagnation or static (blind) pressure for a Silvia, although not the best way to measure it., should be set for 10 - 10.5 bars & for a dynamic simulated or real shot, the pressure set to 9 - 9.5 bars., (1 bar lower to account for dynamic {running} pressure drop) depending on your particular espresso blend recommendations (temp @ grouphead & extraction pressure).
"Well, I just KNEW that there was gonna be a hell of a difference in the shot quality of the Black Cat that I'm using. On my May 2001 Rancilio Miss Silvia, the OPV valve pressure that I didn't know what is was till Fri Feb 23/07 when I completed my portafilter pressure assembly with needle bleed valve., is/was 170 psi! or 11.6 bars. So my readjusted dynamic pressure is 135 - 140psi, a drop of 30 - 35psi or 2.04 - 2.38/2.4 bar. Quite significant IMO.
VERY MUCH sweeter tasting, smoother, no harshness, no blonding, & due to the lower extraction pressure drop from 17.7% - 23.5%., & from my previous grinder setting I had to go 3 notchs coarser or approx 30%.
The very first shot I forgot to readjust my grinder & pulled a very sweet, intense ristretto 1oz with 16 - 17 grams of Black Cat., slightly under dosed La Marzocco style (Ascaso of Spain) ridgeless double basket. Second re-adjusted shot was right on the money, same basket., 18 grams of BC & 1.8 - 2oz.
Brad Ford, the Canadian Intelligentsia rep for Canada recommends & Chicago Intelly recommends running 199.5F/~93C at the grouphead for Black Cat, roughly the same for KidO. They use a Cirqua system to get the water close to SCAA spec and run the pumps dialed back to about 8.2 bar as well. That's what they were running at the Toronto HostEx show as well on a brand spanking new La Spaziale Vivaldi S1. http://www.hostexshow.com/
I was running 198 - 199°F at the grouphead & a little more than 1 bar more pressure (1.3bar more). I wanted to err a little on the high than low pressure side.
I PID'd my machine on June 24th 2006, & the new Rancilio OPV on Sun Feb 25th 2007, dam I WISH I had'a done., or had the money to do the pressure mod then! Cheers, Craig."
Posted Wed Feb 28, 2007, 8:11am Subject: Re: Gaggia pressure problem and subsequent fix
Nice pictures and explanations - I'll have to try and find something similar and then assemble the brass fittings myself since that seems to be a great idea compared to what is being sold for testing pressure. The Gaggia valve fix is pretty interesting as well and maybe I'll open mine up and check that out.
4_40saved Senior Member Joined: 10 Mar 2007 Posts: 4 Location: Gwinnett CountyGA Expertise: Just starting
Posted Sat Mar 10, 2007, 10:44am Subject: Re: Spresso_Bean
Jeff K I am a newbie @ the espresso experience. I just opened my refurb Gaggio Evolution WLL and new Gaggio MM grinder (with no instructions?). I noticed you had the same setup at one time. Would you be willing to answer some questions I have compliled so far? I know one mistake I am already making is using *$ espresso beans. Unfortunately i bought them b4 reading up on the art. My wife has been buying 2 venti latte a day. Thought *$ was the way to intro the home process. hope to hear from you Dean GA
Posted Sat Mar 10, 2007, 12:47pm Subject: Re: Gaggia pressure problem and subsequent fix
Update:
The nice 9-bar pressure I was getting has gone away, and now the machine is back up to about 12 bars (stalled) with the OPV backed out all the way. This is completely inexplicable because I have not modified the machine at all. I blame gremlins.
4_40saved Senior Member Joined: 10 Mar 2007 Posts: 4 Location: Gwinnett CountyGA Expertise: Just starting
Posted Sat Mar 10, 2007, 12:59pm Subject: Re: Gaggia pressure problem and subsequent fix
Chris Does your evolution drip after pulling a shot? The machine is still on and the brew button is off. It's almost like a steam release of sorts. The PF is still in place, so espresso (i'm new so i'll use that term lightly) will drip onto the drip plate. I just bought this refurb from WLL and have a small window to make sure it's running correctly.
For a 2oz pull, maybe 1% of it is crema color. I see these pics of what crema is and I realize I am far from that. Dean
Posted Sat Jan 5, 2008, 2:08am Subject: Re: Gaggia pressure problem and subsequent fix
How do you solder the copper to the stainless basket? I've worked with copper pipe before, soldering fittings - but I'm not sure how this would work. Is there special equipment and/or solder needed? Any tips on making such a connection? I'm working on a pressure gauge this weekend, and will be figuring out how to connect to a blank filter basket next week.
Posted Sat Jan 5, 2008, 3:14pm Subject: Re: Gaggia pressure problem and subsequent fix
stevier Said:
How do you solder the copper to the stainless basket? I've worked with copper pipe before, soldering fittings - but I'm not sure how this would work. Is there special equipment and/or solder needed? Any tips on making such a connection? I'm working on a pressure gauge this weekend, and will be figuring out how to connect to a blank filter basket next week.
Posted Sun Jan 6, 2008, 1:39am Subject: Re: Gaggia pressure problem and subsequent fix
Great, thanks for the tip, I'll give it a try when my blank disc gets in.
I've been reading the forums for quite a while, but I guess that was my virgin post. I am working on restoring a older Gaggia Baby I found on craigslist for cheap - completely torn apart right now, waiting for a rebuild kit on its way from italy :). Can't wait to get it running and finally be able to make great espresso (i've been using, or should I say trying to use, a cuisinart burr grinder and older krups espresso machine for about two years, so the gaggia and rocky are such an upgrade :) )
Symbols: = New Posts since your last visit = No New Posts since last visit = Newest post
Forum Rules: No profanity, illegal acts or personal attacks will be tolerated in these discussion boards. No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum. No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum. Who Can Read The Forum? Anyone can read posts in these discussion boards. Who Can Post New Topics? Any registered CoffeeGeek member can post new topics. Who Can Post Replies? Any registered CoffeeGeek member can post replies. Can Photos be posted? Anyone can post photos in their new topics or replies. Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts. Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
![CraigA: Pict0241.jpg](javascript:ImagePopup("/images/30615/Pict0241.jpg", 352, 288, "CraigA: Pict0241.jpg");)
![CraigA: Pict0318.jpg](javascript:ImagePopup("/images/36704/Pict0318.jpg", 320, 240, "CraigA: Pict0318.jpg");)
= No New Posts since last visit 