I upgraded from a Saeco Aroma to a Gaggia Classic about four months ago. The Saeco gave me delicious espressos with a fine crema, but I wanted to see if I could get an even better shot with a non-pressurized portafilter. So far I've failed with the Gaggia Classic. I use freshly roasted Veracruz espresso beans (bought here in Guadalajara, Mexico) and a Baratza Vario grinder. I've dialed in the grind using the golden rule.
My research has led me to conclude that the only way I'm going to get a decent crema with the Gaggia Classic is to modify the pressure to about 9 bar. I don't have a pressure gauge and I'm not a mechanical engineer. I'll be in Austin, Texas next month and thinking about taking the machine with me to have a technician adjust the machine for me. Does that sound like a plan?
I upgraded from a Saeco Aroma to a Gaggia Classic about four months ago. The Saeco gave me delicious espressos with a fine crema, but I wanted to see if I could get an even better shot with a non-pressurized portafilter. So far I've failed with the Gaggia Classic. I use freshly roasted Veracruz espresso beans (bought here in Guadalajara, Mexico) and a Baratza Vario grinder. I've dialed in the grind using the golden rule.
My research has led me to conclude that the only way I'm going to get a decent crema with the Gaggia Classic is to modify the pressure to about 9 bar. I don't have a pressure gauge and I'm not a mechanical engineer. I'll be in Austin, Texas next month and thinking about taking the machine with me to have a technician adjust the machine for me. Does that sound like a plan?
It seems unlikely to me that your issue lies with pressure. In most cases a crema-less extraction is due to an improper grind setting, distribution errors or the freshness of the coffee. When you say freshly roasted, are you using it within 15 days of roasting? Is there a roast date on the bag?
Your grinder is certainly capable of producing a fine enough grind, so I doubt it's that.
A bit more info here would be welcome. Are you pulling doubles?, singles? ristrettos? Are you timing the shot? If so what sort of times are you seeing?
A quick note on the Aroma that you used previously. Pressurized portafilters will always produce a crema(it's known as fake crema around here) regardless of the grind, tamp, distribution and freshness. It does this by forcing the coffee to exit out of a pin hole in the basket, essentially slowing down the shot and frothing the coffee by introducing air as it pours. There is a BIG difference in the shot quality going from a PPF to a NPPF.
It is easily opened with a 17 mm wrench and the inside turned with an allen wrench. You can turn open about 3/4 turn, counterclockwise. You can add in flow measures out the OPV by occluding the portafilter.
There are several threads on various forums and here, on adjusting OPV. I used Google and entered Gaggia OPV 9 bar and found enough talk through and pictures to get through it without a gauge. You could try that until you see your friend with a gauge and he can confirm and readjust. Pictures and videos are worth a thousand words and you do not have to be an engineer.
I modded a Baby by adding an adjustable OPV to it, and after some work set it to 9 bar during an extraction (about 16g of coffee, about 2oz, about 25 seconds). Works awesome. However - it worked before as well, when it was set closer to 11. If anything I gained some latitude and can be a little sloppy on my variables, but when I was "on" before and "on" now I get the same result (which is a ton of crema that settles like a pint of Guiness). I would suggest that you skip the OPV for now, and try to hit numbers sort of like the above (the more you search the more versions of this you'll find but most will be in that neighborhood).
When I got my Gaggia I went through a lot of coffee until I got things close. If you don't have a scale, I've found that 16g of coffee in a double basket *just* clears the "shower screen" without touching it. Your setup may vary but it'll be close (I believe the Classic and Baby boiler setup is identical). Try various amounts of coffee until you hit the screen and then back it off a touch to give a little airspace and avoid channeling (better to get less great espresso than more mediocre espresso).
[To keep it consistent, it may help to use the basket to scoop your beans. Level the basket off with varying amounts of curvature in your finger to get a few more or less out. Throw them in the grinder and run it completely through. It ain't very precise but it's better than nothing and may give you alternate ideas]
After that I found a large shot glass with a mark at 2oz, and used my phone to watch the time go by in seconds. Adjusted the grinder up and down the scale until I got a setting that gave me that 2oz over approximately 25 seconds (ranged anywhere from about 10 sec to taking so long I gave up). Use a light tamp throughout (and keep it constant as well if you can).
Thanks very much for your suggestions. I found the "valve assembly" in the parts diagram and successfully gave the OPV a 3/4 turn. I don't have the crema I'm looking for yet (still very dark and not too thick) but I'll keep working on it. I'm experimenting with the tamp (30 lbs as measured on my bathroom scale) versus a lighter tamp and will continue adjusting my grind. I am wondering, though, whether the advice given at WLL about measuring the time for the extraction from the moment you turn on the brew switch is correct. It takes quite a while for the shot to start pouring.
If you want to test it, then you can test flow. It is fairly simple. Remove the water supply and substitute 2 glasses. A glass full of water for the water pick up and an empty glass for the return line. Start the machine cool/cold. Hit the steam switch and the brew switch. The steam switch stops the 3 way from opening to brew so no water out the brew head and it has to all go out the return line. You can measure the output into the empty glass for 15 second and estimate 1 minute flow. Here is the flow rate for your pump vs pressure.
The alternate way is to block the output with a blind portafilter and use the brew switch, and not simultaneous steam, and measure OPV output in the return line as above. You likely do not have a blind PF starting out. You can make that fairly easily. Remove the basket and cork the outflow track. I found a wooden dowel about the correct size and made it fit. You can also block with cork, rubber and other possibilities. If you block the basket, not the PF hole, then leave the basket in place. If you actually block the PF as I did then leave the basket out. Lock in place and the pump will pump to OPV return. Do not run for more than about 15 seconds as you are near stalling the pump, though the OPV provides relief. Whatever you figure here to simulate a blind PF will give you the ability to back flush, so worth your time.
Backflush on Gaggia is another topic, well covered in other CG threads.
In most cases a crema-less extraction is due to an improper grind setting, distribution errors or the freshness of the coffee. When you say freshly roasted, are you using it within 15 days of roasting? Is there a roast date on the bag?
A bit more info here would be welcome. Are you pulling doubles?, singles? ristrettos? Are you timing the shot? If so what sort of times are you seeing?
I buy my Veracruz espresso beans from a small coffee shop here in Guadalajara that sells nothing but coffee roasted on the premises. In most cases it is roasted the same day I buy it.
This is what I've been going by: “The Golden rule states that a double shot of espresso should equal 2 to 2.5 fluid ounces and takes approximately 20 to 30 seconds to extract from the moment you start the pump until you reach the appointed liquid volume.”
I am wondering, though, whether the advice given at WLL about measuring the time for the extraction from the moment you turn on the brew switch is correct. It takes quite a while for the shot to start pouring.
I think that I about 4-5 seconds of pump run after I hit the switch before I see espresso out the bottom before. I believe the correct way is to include the whole time on since water is pumped in, you just do not see it as it is absorbed into the puck.
Flavor and consistency are probably more important than whether you count those 5 seconds. You mentioned the creama enhancer, not on the Gaggia I hope. It does not work.
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.
= No New Posts since last visit 