Gaggia Espresso tweaks?

[dookie]

As they say, 'long time lurker, first time poster' and all that, though I would not classify myself as a total novice: home setup is a dialed-in Rocky/Zaffiro combo that I am well-practiced on (pretty much every day for ~5 years) and absolutely thrilled to death with! Now considering a PID, but that's for another thread...

So I just picked up a super-cheap MDF/Espresso setup that I am still deciding on a role for...office or gift? Anyway, I've only pulled a handful of shots on the Gaggia and while they're certainly not up to the level of the Isomac product, I'm fairly pleased with the first pass. The rubber crema 'enhancer' has of course been tossed.

In doing an A/B with the same beans and grinder, the Gaggia shots seem thinner and more bitter. Also significantly hotter. I haven't dug out the temp probe yet to confirm, but I suspect this is a major contributor. Is the thermo-/pressurestat adjustable (or tweakable)? The whole flush/steam bump rigmarole is annoying.

Any other hints from those with experience on this guy would be much appreciated!

Thx,

Kevin

[Beezer]

I had a Gaggia Espresso for years, and I liked it quite a bit. It's a pretty great machine for the money. Unfortunately, the tiny boiler will never give you stable brew temps. Short of installing a PID, I don't there are any tweaks that will give you much control over the brew temp. You can pull a short flush before pulling the actual shot, which will lower the temp a bit and preheat the group a bit more. Other than that, I don't think there's much you can do to regulate brew temps.

I think some of the bitterness might be from the pressure being too high. Unfortunately, the Espresso doesn't have an adjustable OPV, so there's no way to adjust the pressure downward. However, I believe Tim Eggers was having some luck with opening the steam valve during the shot, which acted as kind of a pressure release and kept the pressure from going too high. I haven't tried it myself, but it might be worth a shot (so to speak).

[portamento]

I have thought about opening the steam valve just a hair while pulling a shot on my Gaggia Carezza to reduce brew pressure. The downside is that it would accelerate the temperature drop as well.

[stevier]

Pick up one of these OPV's (comes on the higher-end gaggias, perfect fit on yours), and the shots will likely improve a bunch. Without water going through the OPV on mine, it was around 12-13bar pressure.

http://cgi.ebay.com/ws/eBayISAPI....&item=290213820691

[Beezer]

Interesting. So this OPV just bolts onto any Gaggia? That's pretty cool. Is it adjustable? How would you know whether you're getting the right brew pressure? Seems like you'd have to rig up a portafilter mounted pressure gauge.

[stevier]

Interesting. So this OPV just bolts onto any Gaggia? That's pretty cool. Is it adjustable? How would you know whether you're getting the right brew pressure? Seems like you'd have to rig up a portafilter mounted pressure gauge.

Yeah, fits most any gaggia from the 90's (80's?) and up. It is adjustable, but its a PITA - it has an internal adjustment screw, so you have to partially disassemble it to adjust. And yes, you definitely need a portafilter gauge to get it setup. I have some details and photos from the restoration I did here: http://www.ruizs.org/archives/category/espresso

[lberg]

Hey, guys. Been a lurker here for a while, but have decided to join . I have ordered a Gaggia Carezza and Le'Lit PL53, and they should arrive in a couple weeks (as the Carezza is on backorder). I do have experience with espresso, though. I currently work at my local indie coffee shop. That's how I got into espresso...and here I am, ordering my own equipment.

Yeah, fits most any gaggia from the 90's (80's?) and up.

Looking at WLL's Compare-O-Matic, the Gaggia Baby, Baby Twin, Baby Class, Classic, Carezza, and Coffee ALL are listed as having a "back-pressure relief valve." According to WLL, a back-pressure relief valve is:

Back pressure relief valves serve two important functions. First to ensure that your machine does not brew above the proper "brewing pressure". If the brew pressure is too high then you will get a bitter and overextracted beverage. Also, it protects the pump, gaskets and seals from excess pressure. This feature works by bleeding off water in the boiler to either the reservoir or to the drip tray. All of our machines have this feature.

My question is: Is this "back-pressure relief valve" the same as the Gaggia OPV (or ANY OPV) on Ebay?
Asked another way: How does the "back-pressure relief valve" compare with an OPV?
I may just have to wait until my Carezza comes, then open it up and see what's in there. If this "back-pressure relief valve" is NOT the same as that OPV, then I will most likely end up buying that OPV, because I am interested in making the best espresso I can with that little Carezza FWIW, I'm planning on installing a PID to it soon.

[stevier]

All of them have some form of pressure relief valve (a more formal name for an OPV/"over pressure valve"), but the lower end models are more of a safety valve meant to protect against extreme pressure, instead of the adjustable valve on the higher end model that regulates the group pressure. Basically, the carezza doesn't have a proper one,and you'd be wise to pick one of them up from ebay. The one I listed is pretty much the only one that will work, unless you want to do some custom plumbing.

[lberg]

Thanks for the info. Good to know.

Yeah, on Ebay I noticed there were only 3 available. I don't exactly know if they're going like hotcakes, but in the case that I miss out on them, like you said, I'll have to do some custom plumbing.

Edit: I have purchased one. Thanks for the advice, Steve.

[Beezer]

I think the stock pressure relief valve comes set pretty high, like 12 bar or so. You really want it set around 8 - 9 bar for optimum flavor. So an adjustable OPV is good to have. But then you need some way to measure brew pressure to tell whether the pressure is properly set up. You can improvise a brew pressure gauge with a cheap gauge and some threaded fittings from the hardware store.

[lberg]

Yes. There is this gauge, but at $48, it seems kinda expensive. I would probably be a little better off coming up with my own.

[stevier]

yeah 48 is a bit pricey, but its tough to put together your own - the bottom of a portafilter has a 3/8" BSPT male fitting, which is hard to find here in the states (we use NPT). I pieced mine together from McMaster Carr (mcmaster.com), but I think I probably paid about $50 total for mine in the end - though I did get a liquid filled gauge, and nice needle valve (to measure non-static pressure) out of it.

Or, you can buy this: http://www.chriscoffee.com/produc...arts/faemapfwgauge And i'll buy the portafilter off you for $30

[lberg]

Hmm..oh well, I'll just have to see about it when I get the machine.

[sgstarks]

I have a Gaggia Coffee DeLuxe, and I'd like to retrofit the OPV as described here. I have a portafilter pressure gauge and it indicates 13+ bars static, and 11-12 bars with flow.

I've found the valve at partsguru.com, but have a couple of questions:

1. Does the "exhaust" side of the valve need special tubing? I assume because it will drain to the reservoir with no back pressure that nothing special is required. Is that a valid assumption?
2. The machine currently has a "safety" OPV valve on the pump. Should I leave this in place? Or should I replace it with the "elbow" that ships on units with the adjustable OPV? The drain from the non-adjustable OPV could be used on the adjustable one.
3. Any thoughts or recommendations from someone that has done this?

Thanks,

Greg

EDIT: PartsGuru URLs removed; they don't seem to be working right...