Ceridan Senior Member Joined: 10 Dec 2012 Posts: 31 Location: Prague Expertise: Just starting
Espresso: Rowenta Opio Grinder: Hario Slim
Posted Mon Feb 4, 2013, 6:15am Subject: Gaggia Classic and naked portafilter trouble
Hi!
I lowered pressure in my Gaggia Classic (by 3/4 of a turn, because I don't have the right tools to actually measure the pressure), however when using naked portafilter and single shot basket (and 10 grams of coffee, grind at 6 in Hario Slim) it still spouts all around.
So should I lower the pressure more? Or use double basket and 10 grams of coffee?
AntWilliams90 Senior Member Joined: 4 Feb 2013 Posts: 43 Location: Warwickshire, UK Expertise: I love coffee
Espresso: Gaggia Classic Grinder: Mahlkonig Vario Home Roaster: Dieckmann Rostmeister
Posted Mon Feb 4, 2013, 7:56am Subject: Re: Gaggia Classic and naked portafilter trouble
I don't know how my experience compares, but I am using a naked portafilter with my Gaggia Classic. I use a Mahlkonig Vario (set to 2:E) doserless I tend to dose between 15 and 17g (11 second grind time) into an 18g VST basket I tamp pretty hard...
I get a pretty consistent 26 second pour, no spraying, with really nice tiger striping - and I haven't played with the pressure at all! Just wondering if you've tried a higher dose?
Also, some more details would help... Where does it spray from? Every now and then I get spray from 1 or 2 holes on the basket, which I put down to uneven distribution... What distribution/tamping technique do you use?
As soon as you sit down to a cup of hot coffee, your boss will ask you to do something which will last until the coffee is cold.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,200 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Mon Feb 4, 2013, 9:30am Subject: Re: Gaggia Classic and naked portafilter trouble
I use the double nonpressurized basket and use about 17 - 18 grams, pretty much what it will hold. I can put the pf in the machine dry and not see any indent from the screen screw. I generally see a minimal mark in the center of a wet puck, meaning it expanded to the screen in the center.
I think most people on CG pull doubles only, from what I have read. Doubles are much more forgiving, especially in the learning stage.
Posted Mon Feb 4, 2013, 9:55am Subject: Re: Gaggia Classic and naked portafilter trouble
Do you mean that it sprays out around the basket, or that the extraction through the bottom of the basket sprays around?
The former is due to the top of the basket not sealing tight against the group gasket, either due to dirt, a poor fitting basket/PF or a worn gasket.
The latter is due to inconsistent distribution or inconsistent or too coarse a grind giving channelling in the puck - grind finer, use the WDT to stir and level the grounds, tamp a little lighter, and do not not disturb the puck after tamping by tapping, rotating or polishing. It may be that you can't get a good puck and tamp and spritzer free extraction with a single basket - most of the discussion here about naked PFs is using double or triple baskets.
The other issue is likely to be your grinder - the Hario Slim certainly isn't the best espresso grinder out there, and it may be that it's not up to giving a spritzer free extraction with a single basket. By making a single shot in a naked PF you are basically trying to do the thing that is most demanding on machine, distribution/tamp technique and grinder here.
I had to adjust my Classic by a bit more than 3/4 a turn when I did it with a pressure gauge as well. Too high a pressure will make brewing a naked single even harder.
You could also try a pseudo-preinfusion to see if it helps the taste and extraction (in that order ;) ) - turn the brew switch on for a second or two, then turn it off, wait 5 seconds, and then finish pulling the shot. But I didn't like that using the built in preinfusion function of the Auber PID kit I installed on my Classic.
tracerbullet Senior Member Joined: 13 Feb 2012 Posts: 152 Location: Saint Paul Expertise: I love coffee
Posted Mon Feb 4, 2013, 3:24pm Subject: Re: Gaggia Classic and naked portafilter trouble
Agreed that's a distribution problem. Something that has helped me is to stir up the grounds in the basket a little w/ a toothpick, tap the basket gently on the countertop, and repeat for any high spots left until it's all pretty uniform. Next I put the basket into the portafilter and tamp. Everyone seems to have their own methods, you'll just have to find yours.
The bottomless portafilters are fun and educational, though slightly annoying! You will learn quickly about distribution problems and such, spraying coffee around in the process. I've learned to keep my glass up near the portafilter while it's brewing, or I end up going to work with coffee stripes on my shirt.
I'm a big fan of these: http://www.espressoparts.com/EPMEAS , I can keep it near the portafilter to keep myself and the countertop clean, but still see what is going on through the clear glass. The markings on the glass also help me to know how much I've brewed as far as keeping things consistent from one shot to the next.
Ceridan Senior Member Joined: 10 Dec 2012 Posts: 31 Location: Prague Expertise: Just starting
Espresso: Rowenta Opio Grinder: Hario Slim
Posted Tue Feb 5, 2013, 3:12am Subject: Re: Gaggia Classic and naked portafilter trouble
Thank you all for the replies.
Basically I should: - Grind finer. - Tamp more thoroughly (I admit I have to practice there and get a better tamper). - Aim for a double shot for the time being.
And as an added benefit get this cool glass :) http://www.espressoparts.com/EPMEAS (Good luck finding them in Czechia, probably I'll just create one using and ordinary small glass :) )
ggcadc Senior Member Joined: 25 Mar 2008 Posts: 146 Location: San Diego, CA Expertise: I live coffee
Espresso: QM Alexia Grinder: Mazzer mini E, Virtuoso,... Vac Pot: Yama 3 cup Drip: All of them Roaster: Behmor 1600
Posted Tue Feb 5, 2013, 8:42am Subject: Re: Gaggia Classic and naked portafilter trouble
you can estimate the pressure by using the return flow tube in a measuring cup. if you look into it there is a thread around here that describes the procedure and amount of water to expect for 9 bars. other than that, just know that the classic is very fussy about distribution and grind.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,200 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Tue Feb 5, 2013, 10:54am Subject: Re: Gaggia Classic and naked portafilter trouble
The flow rate of a ULKA pump is about 600-650 cc/min with no back pressure and at 9 bar, the flow is about 250-260cc/min. If you remove the water reservoir and put a glass of water for intake and an empty glass for output, then you can measure the output. Use a blind basket to completely obsrtuct the group and run the opv/return tube into the empty outflow glass. Time from first drip out the tube for 15 seconds and measure. About 60-65 ml is good for 15 seconds. This is an approximation, but is an easy way to check your blind adjustment.
Flow vs pressure for various ULKA pumps. The E5 series is commonly used.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,200 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Tue Feb 5, 2013, 11:04am Subject: Re: Gaggia Classic and naked portafilter trouble
Ceridan Said:
Thank you all for the replies.
Basically I should: - Grind finer. - Tamp more thoroughly (I admit I have to practice there and get a better tamper). - Aim for a double shot for the time being.
And as an added benefit get this cool glass :) http://www.espressoparts.com/EPMEAS (Good luck finding them in Czechia, probably I'll just create one using and ordinary small glass :) )
If you do all of this at once you may choke the machine. Going from single dose to double will be a big change. Also, you mentioned tamping. Tamping pressure may be over-rated, but even tamping, to a consistent pressure, with a single fitted tamper is important. Good shots were near impossible with the plastic tamper included with the Gaggia. It took several tamps and made an inconsistent puck.
Ceridan Senior Member Joined: 10 Dec 2012 Posts: 31 Location: Prague Expertise: Just starting
Espresso: Rowenta Opio Grinder: Hario Slim
Posted Wed Feb 6, 2013, 8:12am Subject: Re: Gaggia Classic and naked portafilter trouble
D4F Said:
The flow rate of a ULKA pump is about 600-650 cc/min with no back pressure and at 9 bar, the flow is about 250-260cc/min. If you remove the water reservoir and put a glass of water for intake and an empty glass for output, then you can measure the output. Use a blind basket to completely obsrtuct the group and run the opv/return tube into the empty outflow glass. Time from first drip out the tube for 15 seconds and measure. About 60-65 ml is good for 15 seconds. This is an approximation, but is an easy way to check your blind adjustment.
This looks promising. Please, which of the hoses is for the input and which for the output? Are we talking about these to normally connected to the GS's water tank?
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