Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Espresso Mods and Restorations
Gaggia OWC - (Very Old) Old White Coffee - new mods
Commercial Equipment
Nuova Simonelli, La Marzocco, Rancilio. Nationwide installation. Instant financing options.
www.seattlecoffeegear.com
 
Not Logged in: Log In to Postlog in
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered  
Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Discussions > Espresso > Espresso Mods > Gaggia OWC -...  
view previous topic | view next topic | view all topics
showing page 1 of 3 last page next page
Author Messages
AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Sat May 26, 2012, 2:32pm
Subject: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

==========
In case you don't want to read this whole, long post -- the punchline is that I posted a video showing me pulling several back to back shots with this very old Gaggia while measuring with a ThermoFilter device - demonstrating that I can pull several back to back shots with proper brew temp and while holding a fairly constant brew temp during the pull. YouTube link at the end of this post.
==========

I have been experimenting a bit with the OWC.  I love the large boiler - it is about 3 times larger than the Gaggia Classic.  Sadly there were three or four design mistakes that caused this model to be considered a dog.

The positive about this old model:
Larger Boiler - came with 3-way solenoid valve - came with a good OPV - same case design as the modern Classic model.

The Negatives (design flaws):
OPV on boiler bleeds off heated water (cools the shot). The standpipe inside the boiler takes cold water from the bottom of the boiler (right next to the incoming water port).  There is no dispersion disc - the group has one, small outlet hole that sprays high pressure water and drills a hole in one side of the coffee puck.

My mods (most of these were detailed in an older post).  
I added a dimmer to the pump so I can vary the pressure and flow of the pump from 1 bar to 12 bars (or higher if desired  by tightening the OPV).  

I re-routed the water inlet to the OPV so only cold water is bled off by the OPV (now, with the variable power pump this mod may not be needed but it still makes more sense to have the OPV bleeding cool water from the pump rather than hot water from the boiler).  The keeps the brew temp much higher during the shot - previously the shot temp would plummet as cold water rushed into the boiler and hot water was bled off by the OPV.

I blocked the hole at the bottom of the standpipe.  The Gaggia Classic and other Gaggia models all take water only from the top of the standpipe where it is hotter than the incoming water at the bottom of the boiler.  The OWC had a hole through the standpipe at the very bottom allowing cooler water to go to the group and also preventing the boiler from filling all the way.  Now the water must be at least up to the top of the standpipe inside the boiler before it can flow to the grouphead.

The 112C brew t-stat on this older model was now too hot (they probably picked such a hot T-stat to try and compensate for the rapid cooling caused by the previous design flaws).  I replaced the T-Stat with a 100 degree C t-stat which is just a tiny bit too cool and then I use the steam switch for a few seconds to get the boiler up to my target temp.

I mounted an inexpensive ($10 at BBBY) digital thermometer with the TC bead pressed against the side of the boiler - this allows me to get right to my target shot temp using a couple of brief blips of the steam switch.

I created a dispersion disc that goes between the shower screen and the group head and gives a nice, even dispersion to the puck.

I made a low res video (using my phone - I need to get a real video cam one of these days) and posted on YouTube.  This video demonstrates the variable pressure using a PF mounted gauge and shows how easily I can pressure profile.  And then I pull about six back to back shots with a homemade ThermoFilter showing that I can hold the brew temp during the shot as well as pull back to back shots without any loss of temp stability.  (I hit the steam switch for about 10 seconds at the end of a shot, wait about 4 seconds and then start the second shot)

http://youtu.be/Wo97AGMLqb0
back to top
 View Profile Link to this post
D4F
Senior Member


Joined: 15 Mar 2012
Posts: 1,981
Location: USA
Expertise: I like coffee

Espresso: Gaggia Classic PID
Grinder: Baratza Forte-AP
Posted Sat May 26, 2012, 6:58pm
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Great video.  Once again you are the PID, or better :) .  Is this the machine?

Click Here (www.partsguru.com)

Where is the element, what is the tank?  How many watts?

?

 
D4F also at
http://www.gaggiausersgroup.com/
back to top
 View Profile Link to this post
AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Sat May 26, 2012, 7:51pm
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

That looks as close as you're going to find to this machine.  A couple of things are slightly off but that's it.  The heater is in the upper half of boiler but it's not the same heater as the newer Gaggia boilers.  Still embedded in the aluminum but the boiler is round and measures quite a bit more volume.  One other benefit - this thing steams milk like you wouldn't believe - really powerful steaming.

Not much information on this thing - it was made over 30 years ago - can't tell you the wattage.

Other than picking the starting temp ... I'm not touching the heat during the shots.  The temp stability during the shot is purely the large boiler, the heat is not on at all until the shot ends and I turn it on for 10 seconds.
back to top
 View Profile Link to this post
SJM
Senior Member


Joined: 17 Nov 2004
Posts: 1,707
Location: CA
Expertise: I love coffee

Espresso: SAMA, Gaggia Classic
Grinder: K-10PB, Rancilio MD-50
Vac Pot: no like
Drip: no like
Roaster: HotTop
Posted Sun May 27, 2012, 7:50am
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Several members of the Gaggia Group have this old model, so we have quite a bit of accumulated information on it.  A member just recently did a test on the actual boiler capacity, and (if memory serves me correctly) it is 8.5 oz.  

We affectionately (and sometimes not so affectionately) refer to it as the F*OWC.
When trying to distinguish it from the "New" Coffee, we call it the Old White Coffee with the Steam Knob on the Front.

Gaggia made some changes to it (getting rid of the round boiler, adding a separate brew group), and re-named it the Classic.  Then they started making the "New" Coffee without an adjustable OPV or a 3-way solenoid.  (IMHO a marketing decision made by a committee on a Friday afternoon)

It is a workhorse of a machine, whose primary "failing" is that replacement parts are hard to find.  Best bet if you find one of these (on eBay for example) is to buy two so that you have parts.
back to top
 View Profile Link to this post
AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Sun May 27, 2012, 8:29am
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Yeah ... I dread the thought of trying to find parts - mainly the boiler, group and that ring that locks the PF to the boiler.  Most of the rest of the parts could be substituted. There is one place that has new old stock boilers (but only in 220v version).

I've thought of putting the nice, articulated steam wand from a Silvia V3 on there - but instead I just straightened out that stock, fixed steam wand a little so it will fit larger pitchers and it works fine.

Before this last round of modifications, I was just about to get rid of all my Gaggia's (I have about 10 different models - I'm obsessed) and move to something like a Bezzera Strega.  But now I'm not so sure how much I can improve on this ancient Gaggia - I've got total pressure profiling and with my little routine I'm able to get pretty steady temps (even for back to back shots) and this old beast steams great too.

But ... it does seem a bit nutty for me to keep hacking away at these little Gaggias instead of just getting a nice HX
back to top
 View Profile Link to this post
SJM
Senior Member


Joined: 17 Nov 2004
Posts: 1,707
Location: CA
Expertise: I love coffee

Espresso: SAMA, Gaggia Classic
Grinder: K-10PB, Rancilio MD-50
Vac Pot: no like
Drip: no like
Roaster: HotTop
Posted Sun May 27, 2012, 12:09pm
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

AndyPanda Said:

Y
But ... it does seem a bit nutty for me to keep hacking away at these little Gaggias instead of just getting a nice HX

Posted May 27, 2012 link

I can relate right up to that part about wanting an HX.  I had a closet full of old Gaggias, some of which I rebuilt, some of which I parted out, all of which I eventually sold for peanuts.  Now I am content with my new-to-me PID'd Classic with a Silvia wand.  I have no more interest in tinkering, and no interest whatsoever in an HX.  The small single boiler is perfect for a one-person household and I"m set.

Keep the mod fires burning.  My modding days are over and done with.
back to top
 View Profile Link to this post
Snowboarder27118
Senior Member


Joined: 13 Apr 2011
Posts: 11
Location: Boulder,co
Expertise: Just starting

Posted Thu Jun 14, 2012, 7:16pm
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Hey Andy love the work you've done on your OWC since the last time I logged on! I've still only done the aluminum can mod but am eager to improve my machine more.

The first thing I want to do is switch out the old aluminum can with a new disk. I noticed in another thread you suggested using stainless or copper instead of the brass that you used to make your new dispersion disk. Is there a reason you suggest the stainless or copper over the brass? Also did you use a washer as a spacer to prevent the new disk from becoming a reed valve?

I also want to fix the pressure/heat issue of the machine. At first I was going to do what you first did rerouting the water inlet to the OPV valve but then I saw your post about adding a dimmer to the pump. Would you say that this is an easier/quicker solution to the design flaws of this machine? Do you have a more lengthy post explaining how you did this?

Thanks!
Kyle
back to top
 View Profile Link to this post
AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Thu Jun 14, 2012, 7:50pm
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Snowboarder27118 Said:

Is there a reason you suggest the stainless or copper over the brass?

Posted June 14, 2012 link

Only that so many posts have someone worrying about ingesting lead from brass in their espresso machines.  Apparently there are many different types of brass and the stuff I bought at the Hardware store wasn't specifically meant for food equipment.  I don't really worry very much about it but maybe I should - I really don't know.  But stainless would probably be safer (until someone posts and tells me that stainless will poison me).

Snowboarder27118 Said:

Also did you use a washer as a spacer to prevent the new disk from becoming a reed valve?

Posted June 14, 2012 link

No.  I have two machines and I did it two or three (or a dozen) different ways - the ugly way worked the best but would really bother most people (especially the ones worried about brass poisoning).
 
Method #1 -- (the one I've been posting recently) there is a ridge around the edge of the group head.  As long as you make your disc full size so it goes all the way to the very edge, it will be held up about 1mm above the surface where the hole is (if you use a little stiffer material than the beer can - this is also why I went to the hardware store and bought the brass sheet - stiff enough to not become a reed valve). The shower screen won't make a tight seal at the edges so I had to fabricate a thin o-ring/gasket around the edge of the disc so the shower screen edges would seal tightly.  You lose a tiny bit of headroom which is fine with me because I like to underdose anyway.

Method #2 -- dimple the surface of the disc on both sides then it cannot make a seal and act like a reed valve.

Method #3 -- I used a dremel with a cutoff wheel on the other machine and ground a series of ditches for the water path to four holes in the disc.  I used a thicker piece of aluminum (hold it's shape) and made the circumference small enough that it sat directly down against the metal surface with no gaps (so the water had to flow through the channnels I made).  Then I had to fabricate an o-ring (couldn't find one the exact right size) to go around the this thicker disc so the shower screen would seal at the edges and have a little bit of space between the disc and the shower screen.  This method actually worked the very best of anything I've tried - very smooth dispersion - but I think if anyone actually saw it they would roll their eyes and call me an idiot.

Snowboarder27118 Said:

I also want to fix the pressure/heat issue of the machine. At first I was going to do what you first did rerouting the water inlet to the OPV valve but then I saw your post about adding a dimmer to the pump. Would you say that this is an easier/quicker solution to the design flaws of this machine? Do you have a more lengthy post explaining how you did this?

Posted June 14, 2012 link

The intent of the dimmer was NOT to solve the OPV issue (since I had already re-routed my water inlet) -- I did that so I could try various pre-infusion pressures and also because I had read some posts where Jim Schulman was doing lower pressure pulls to get great shots using certain coffees that normally only work for brew.  And I was delighted to learn that I could get some really great, espresso strength shots from some light roasted coffee that normally wouldn't work as espresso - it really worked great for me. Though I mainly pull normal pressure shots and don't even do any special pre-infuse much now -- I just leave the dimmer at the same place all the time which give a really gentle ramp up to 9.5 bars which seems to be just perfect without any tweaking of the dimmer once it's set.

I noticed that at the dimmer setting I like best, I am getting 9.5 bars and only one or two drops form on the OPV return line to the water tank.  You may need to adjust the OPV differently because the pump isn't pushing so hard (because the OPV works on a spring that is not being squeezed as hard now).  But it would totally allow you to pull 9.5 bar shots without re-routing your water line and without losing any hot water from the boiler. You'd just have to practice with a PF gauge and adjust your OPV a bit and then notice where to set the dimmer that just barely drips a few drops past the OPV.
back to top
 View Profile Link to this post
AndyPanda
Senior Member
AndyPanda
Joined: 12 Jul 2010
Posts: 769
Location: San Francisco Bay Area
Expertise: I love coffee

Espresso: Olympia Cremina, Various...
Grinder: Mazzer Major, Fiorenzato,...
Vac Pot: vintage Corey
Drip: AeroPress
Roaster: BreadMachine/HeatGun
Posted Fri Jun 15, 2012, 7:14am
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Just for fun, I made a video of the shower screen so you can see how evenly it disperses now.  This is the one I showed the most recent pictures of with the disk made of brass with 12 small holes.   One other mod I did (just last night) that improved things even more --- there is an older post here from someone else (sorry I forget who - or I would credit the idea where it is due) who mentioned drilling out that tiny hole in the group head where the water shoots out.  I drilled that last night so instead of being the tiny (like 2mm) hole where water really shoots out fast, it is now about 5mm around and the water runs out much slower.   So that's just one more piece of the puzzle that is pretty easy to do.  The hole is MUCH deeper than I thought it would be - that is one thick piece of brass - poke a paperclip down the hole to see how deep it is so you know how deep to go with the larger drill bit.  It really surprised me how deep.

Here is the video of the shower:
http://youtu.be/iQxvZOXmR1E
back to top
 View Profile Link to this post
Snowboarder27118
Senior Member


Joined: 13 Apr 2011
Posts: 11
Location: Boulder,co
Expertise: Just starting

Posted Fri Jun 15, 2012, 6:21pm
Subject: Re: Gaggia OWC - (Very Old) Old White Coffee - new mods
 

Wow I don't think you can make that shower screen and better! It looks great. I might have to take on the drill project now too. I took my machine apart to do some deep cleaning (as my machine that's older than I had a bit of rust going) and found that my aluminum can dispersion screen is disintegrating. So it's definitely time for a different solution.  So yesterday I went on a hunt for a slab of copper or stainless but the only thing home depot or lowes had was aluminum or galvanized metal. Its funny that everyone is freaking out about this brass since I thought aluminum was the thing everyone was worried about. So I guess I'm going to have to try another store to find stainless or copper, maybe Ace is next.

While I was at Home Depot yesterday I purchased a rotary dimmer in hopes that it might be the right thing. I'm not much of an electrician or an engineer but I really want to get good espresso going and am willing try anything I can to get there. It seems that although the dimmer wasn't first used to solve the hot water/ OPV valve issue that it has indeed done so. I like the idea adjusting the pressure of the pump with the dimmer but do you think it's necessary to make/buy a PF gauge or do you think it would be ok to just monitor the flow of the OPV valve until I get it down to just a couple of drops going back to the reservoir? Also, do you think the dimmer mod is more challenging to complete than the re-routing of the water inlet?

Any pictures or further direction that you could help me with on the dimmer and/or the water inlet re-rout mods would be greatly appreciated.

Thanks,
Kyle
back to top
 View Profile Link to this post
showing page 1 of 3 last page next page
view previous topic | view next topic | view all topics
Discussions > Espresso > Espresso Mods > Gaggia OWC -...  
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered     Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Not Logged in: Log In to Postlog in
Discussions Quick Jump:
Symbols: New Posts= New Posts since your last visit      No New Posts= No New Posts since last visit     Go to most recent post= 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 SEO style postings will be tolerated. SEO related posts will result in immediate ban from CoffeeGeek.
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.
Don't suffer bad espresso
Package deals on the best machines from Izzo, Quick Mill, VBM, La Marzocco & more.
www.clivecoffee.com
Home | Opinions | Consumer Reviews | Guides & How Tos | CoffeeGeek Reviews | Resources | Forums | Contact Us
CoffeeGeek.com, CoffeeGeek, and Coffee Geek, along with all associated content & images are copyright ©2000-2014 by Mark Prince, all rights reserved, unless otherwise indicated. Content, code, and images may not be reused without permission. Usage of this website signifies agreement with our Terms and Conditions. (0.294365882874)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+