Gaggia Classic notes

I’ve been doing some more maintenance on the Gaggia Classic. When I got it back from NY it was a bit choked what with the mineral deposits from that hard Catskill aqueduct water. So I disassembled it (photos here) but the one tiny port that I somehow didn’t read up on (or take apart and clean) was the 3-way solenoid valve (it requires a large wrench and possibly you’ll need to screw the 3-way solenoid into a piece of wood to get leverage on it, read Steven Heaton’s post here and Christopher Reed’s here).

Similarly, on the OPV valve (which I did disassemble, more info on that at Ruiz’s blog), I potentially over tightened the “over pressure” spring adjustment. So between the two (one likely blockage in the solenoid and too high of ‘over pressure’) I was getting some wonky behavior: occasional air-locks, high pressure into the puck, inability to clean by backflushing Cafiza.

Without a pressure gauge hooked up to a threaded portafilter all my “pressure adjustments” have been blind, however this time I did try and hit the recommended “over pressure flow rate” which is in the neighborhood of 130 ml for 30 seconds (using a blank basket). It does take a few adjustments to get it right, and I imagine if I put an actual gauge on it (which might be possible using a Presta valved bicycle inner tube and an actual bicycle pressure gauge) it’ll need to be adjusted further (10 Bars static, 9 Bars dynamic being the goal). My existing portafilter just has two spouts and is not threaded in the middle and I’d rather not splurge and spend another $50 for a portafilter I’m only going to use once, apparently there are a few floating around as loaners, so if you’re a Gaggia Users’ Group member and have one I’d be happy to pay a deposit and shipping to at least get the machine’s pressure set.

Gaggia little Gaggia, the light of my life.

Found a used Gaggia Classic on newyork.craigslist.org.  Took the train up to Greenwich, paid the the cash to the pusher man in the back of his SUV and took home a “marginally used” single pump/single boiler w/3 way solenoid valve home espresso machine.  The Rancilio Silvia currently goes new for about $600 or more, the Gaggia Classic is usually just under $500.  I paid less than half of that so I feel good about it.  Now the grinding, that’s another story.  My vintage PeDe hand grinder goes pretty fine, but it’s still a bit coarse for the Gaggia.  I had Ellen at Sweet Leaf grind me some Hairbender with their Mazzer profi grinder and it’s perhaps too fine; I’ll try less tamp.  This morning it has tended towards a bit sour extraction though blonding doesn’t seem to be happening as quickly and I’m getting the full 30 seconds if not more, which makes me think it’s too fine.  With the Larry’s espresso I was using and the PeDe I was getting 15 seconds max but it was much sweeter, though likely much less extracted, so it’s a fine line.

So yeah, at this point I have some cleaning to do: back flush the porta filter basket and 3-way valve, and do a full descale of the system.  So far it doesn’t look like it was too heavily used though when I pulled the screen off the group head there was a pretty serious buildup of coffee soot/sludge so I’ll likely need to do a bit of cleaning around the group.

Gaggia Classic Espresso Machine

Gaggia Classic Espresso Machine

I did find a few terrific videos concerning grinding and cleaning I’ll link to here, from Seattle Coffee Gear and their blog here, The Brown Bean:


HTML5: http://youtu.be/N7Bn5IjZht8


HTML5: http://youtu.be/hLoaIWmufKk


HTML5: http://youtu.be/bxpOBZyK9MA


HTML5: http://youtu.be/uiP-6ZLJpp4