Gaggia Classic, several problems with brand new machine

Need help with equipment usage or want to share your latest discovery?
unfinishedsweet
Posts: 4
Joined: 11 years ago

#1: Post by unfinishedsweet »

Hello there

First of all, I am new here so hello to everyone. Although been reading forums for longer time it is a first time I am posting.

I have purchased Gaggia Classic not long ago as I tried espresso from it at someone's place and been given great reviews from many people I spoke to.

First problems were I suppose obvious to you, high brewing pressure and useless basket with one hole in the middle. I got proper basket that made major change in my espresso, I have also reduced the pressure to recommended static of 10 bar. However I have managed to sort of test the actual working/brewing pressure by fitting isolator on the same line as the gauge and when just slightly open the gauge showed about 9.5 bar that I would think is a little bit too much, no further work done on it though.

After a month of using useless filter basket supplied, I have noticed that machine got dirty and full of grinds in the shower and water lines so decided for backflush. I used proper chemicals, backflushed, cleaned all through properly and after this I have noticed that shower started working as a shower. When the machine was new and before any work/mods done on it when I ve been flushing the steam out from it before brew, I remember the laminar stream of water were coming out from the centre of the shower. After backflushing, reassembling etc it started 'showering' like proper showerhead in my bathroom. Taste improved too.

The last problem I am still having is the puck. It is always wet, with a little pond of water on it when the brewing is finished. If I knock it out is falls into pieces, wet, saturated horrible. I think is even worse after backflushing or maybe not as never been good so hard to say.

I always use fresh beans grinded on Mazzer SJ, I have used right weight of coffee, dialled grinder to achieve 27-30s for 60ml. Not bothered for it now, just fill up portafilter to required level, tamp it, brew.

The tamper has convex surface as the basket is similar shape so chosen this one.

My worry is that either the pressure is still too high (I think it is worse since first (and the last) backflushing). Grinder is dialled in very low, between 3/4 - 1 mark on the wheel, brews quite quickly, I think it was slower before at higher setting (changed beans though), starts blonding quickly, puck is wet, saturated...the taste.. well sometimes fairly good, would even say not bad at all, many other times have to spit it out.

Recently I visited friend that served me a shot from his old slivia and rocky kit, was amazing and the puck was dry and in nice one piece, I was shocked cause my one is nowhere near.

Before I strip it down and start playing with pressures again I would like to know your opinions, I will definitely measure the pressure again as having a feeling it has changed or something in the machine did or maybe there is something else that I have missed. I am new to brewing thus all I have done so far is based on the knowledge from this forum and articles on web or youtube.

One more clue, could OPV get damaged when backflushing? Nothing silly was done so I would not expect it. There is one more thing I would like to mention, sometimes I notice water on the counter behind the machine and I think this happens when I fill up container form a kettle shaped filter and I pour the water into built in funnel with a little angle. I opened the machine once and was dry inside, not sure but it happens only after filled up. I looked once above container and there was stream of water on back stainless steel wall. When pulled machine from under the above cupboards and had more room above to fill up I haven't noticed any water escaping. I wonder if any of you guys had similar experiences with this machine. I spoke to someone in Italy once that sells all sorts of different machines and assured me that Gaggia Classic is state of art machine in its class, so I wonder if just mine is not right or what.

Was thinking about VST basket but, will not spend any extra on the kit until will be satisfied from what I have got now.

Thank you for your opinions ant time spent on reading this post.

Pat

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xtal
Posts: 43
Joined: 11 years ago

#2: Post by xtal »

They gave you a basket with one hole in it? :shock:

Todd Salzman
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#3: Post by Todd Salzman »

The filter basket with one hole in it is a pressurized one. It is normally only used by people that do not have a grinder. The machine also came with a commercial double filter basket (if you are in the USA) and that is the one most people use.

Doing a backflush will have not effect the OPV.

If you get a little water on top of the coffee puck just add in a little more coffee before you tamp, that will solve the water and the sloppy puck issue.

Hope this helps.

Todd
Todd Salzman
Whole Latte Love

unfinishedsweet (original poster)
Posts: 4
Joined: 11 years ago

#4: Post by unfinishedsweet (original poster) »

I have managed to get proper basket and discarded one hole useless one. Water pond and wet puck still exists with proper basket. If I top it up with coffee. That will mean I put well over 20g of grinds for double shot. Do you think it is a basket problem? What pucks come out of your gaggias. I have the problem even if I fill it up to the rim. I would have to top up after tamping and tamp again. Puck also has several holes in it often.

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happycat
Posts: 1464
Joined: 11 years ago

#5: Post by happycat replying to unfinishedsweet »

Hello friend. Welcome to the Gaggia club!

If your puck has holes in it, you may have a channeling problem (where the water coming from the shower under pressure passes through the weakest part of your puck instead of saturating it). Have you tried stirring your ground coffee with a chopstick or cake tester needle before tamping? Is your tamp a reasonable (not too much) pressure? If it's too hard, or you do it multiple times, you may have issues.

As for a wet puck... when you switch off the brew switch on the Gaggia, the 3-way valve engages and is supposed to suck the water out of the portafilter and spit it out a tube at the front of the machine into the drip tray. That's the same tube you back flush out of. A wet puck in itself is not a big deal, but it sounds like you are have channeling problems so try to deal with those with the stirring the grinds.

What kind of basket did you buy? Is it a standard double? You should be able to get an OK shot with 14-16 gm in a standard double basket.

Some other hints....

- focus on watching the colour and viscosity of the streams coming out of the brew head... you want 25-30 seconds of tiger-striped brown before it goes beige/white/transparent ("blonding"). By watching that stream you can figure out whether you are grinding fine enough, or whether you are having some channeling problems.

- note that the Gaggia has a pretty bad temperature control... so that will affect taste in a big way. The heater will only come on at a low temperature, and will stay on until a too high temperature. You can get a PID (Auber Instruments) or you can make do with a kitchen digital thermometer... I fed the metal probe of a kitchen thermometer through the back vents and jammed the metal probe between the upper posts of the boiler inside... this is not an accurate temperature, but it is a consistent temperature reading... you can heat the Gaggia up by flicking the steam switch on and off, and you can cool it by pressing the brew switch to let hot water out NOTE: those thermometers may have a delay... I think mine was delayed 30 seconds or so before noticing a temperature change

- note that you can get a poor man's preinfusion to wet the coffee puck at very low pressure by opening the steam valve a bit before you press the brew switch, then press the brew switch, and then closing the steam valve after a couple seconds (or when water comes out the steam arm).

I have since installed a PID brew/steam temperature controller on my Gaggia, upgraded the steam arm to the Silvia V2, bought a couple VST baskets, and wired a 600W dimmer switcher between the brew switch and the pump for dynamic pressure control.

I backflush after every brewing session but I just do it without any chemicals... just water. This helps clean out the brew head (although the shower head still seems to get gummed up so you need to disassemble that weekly or so).

Good luck!
LMWDP #603

unfinishedsweet (original poster)
Posts: 4
Joined: 11 years ago

#6: Post by unfinishedsweet (original poster) »

hello happycat!

thanks for very comprehensive reply. I'm also planning to modify the machine to add more control on rhe pressure and a way of monitoring the temperature. I have noticed problems with temperature variations on this machine, so would be good if you could help out with some pictures or more details about your mods. I will obviously reply with my designs of mods.

I actually do have problems with the holes in the puck. I probably tamp too hard. was also blaming the basket and possibly excessive pressure. I think I'm going to plumb in some permanent pressure gauge. have to study the machine a bit more though, still lacking the time to implement the ideas.

Going back to baskets. I have the original double that I received from Philips after quoting original part number. I'm considering buying some better basket and possibly bottomless porta filter. I wanted to start another thread about it, basically considered vst baskets but could not work out which one is best for my machine. ridged ridgeless what size etc. I like both creamy smooth Italian way shots and those mouthful thicker ones. Referring to many sites I should be pulling 60ml shot in about 27s from 12-14g of grinds. at the moment I fill the basket up to the rim and level with finger so I suppose it is bit more than 14g. I'm not quite interested in scaling every dose so would rather fill the basket to the rim and level. is that the way to do it?

Could you guys then recommend make and model of basket that would fit well to my machine. If VST which one? Should I also buy bottomless filter for best results? I do love crema and I do love loads of it.

Please advise and suggest some clues. I cannot afford 6k machine so need to modify/improve my existing one.

I was also thinking about plumbing my gaggia to water line though worried about excessive water pressure. Any ideas what sort of pressure would be safe for machine? I would like to avoid floating valve in tank and would prefer fresh water straight from pipeline. Thinking about reverse osmosis filter before it too and drain off from drip tray to the waste.

Cheers
Pat

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happycat
Posts: 1464
Joined: 11 years ago

#7: Post by happycat »

unfinishedsweet wrote:I have noticed problems with temperature variations on this machine, so would be good if you could help out with some pictures or more details about your mods. I will obviously reply with my designs of mods.
I bought the PID kit from Auber Instruments. It comes with a DIY install guide. As for the kitchen thermometer, it's pretty easy to pop the top of the Gaggia, feed the probe through the vents and jam it between the top posts of the boiler.
unfinishedsweet wrote:I actually do have problems with the holes in the puck. I probably tamp too hard. was also blaming the basket and possibly excessive pressure. I think I'm going to plumb in some permanent pressure gauge. have to study the machine a bit more though, still lacking the time to implement the ideas.
If you've already toned the pressure down to 9.5, you probably want to make sure you have an even distribution of grinds. After grinding stir them up with a chopstick or cake tester. A tamp should be a single even press. Or you can try a nutating tamp which is placing the tamper on the grinds in the portafilter and doing a light angled rotation before a single firm downward even tamp. The idea is to have even distribution of grinds.
unfinishedsweet wrote:Going back to baskets. I have the original double that I received from Philips after quoting original part number. I'm considering buying some better basket and possibly bottomless porta filter. I wanted to start another thread about it, basically considered vst baskets but could not work out which one is best for my machine. ridged ridgeless what size etc. I like both creamy smooth Italian way shots and those mouthful thicker ones. Referring to many sites I should be pulling 60ml shot in about 27s from 12-14g of grinds. at the moment I fill the basket up to the rim and level with finger so I suppose it is bit more than 14g. I'm not quite interested in scaling every dose so would rather fill the basket to the rim and level. is that the way to do it?

Could you guys then recommend make and model of basket that would fit well to my machine. If VST which one? Should I also buy bottomless filter for best results? I do love crema and I do love loads of it.

Please advise and suggest some clues. I cannot afford 6k machine so need to modify/improve my existing one.
It's worth weighing your coffee. It really is. Get a little scale and weigh your beans before grinding so you are consistent. Going by volume is just going to make your life inconsistent and challenging. As I mentioned, diagnose your shots based on watching the pour. It's not just how much you get in a given amount of time, it's getting tiger-striped brown for most of that pour time. Otherwise you could be channeling.

As for VST, I have both ridged and ridgeless. I prefer the ridgeless, but when I knock the puck out I do it by tapping the basket part against a coffee can so the basket doesn't fall out. A VST obviously isn't necessary. I bought them for a number of reasons. First, the holes in my stock Gaggia basket weren't very cleanly punched. Second, I was playing with updosing and wanted some more space in my basket. Third, I understood that you could put more coffee in a VST and still have a similar flow rate due to the number of holes so you could use a finer grind than other bigger baskets. As I was playing with preinfusion, I wanted to try going a lot finer to see what the results would be.

As for bottomless portafilter, most people seem to use them to learn how to distribute their grounds evenly and diagnose channeling. They don't seem to use them for day to day use. Personally I can't be bothered with the expense and trouble. I did take the spouts off my portafilter so I can tell basically if there are distribution problems. Note that taking the spouts off requires a lot of leverage due to some kind of locking sealant on the bolt.
unfinishedsweet wrote:I was also thinking about plumbing my gaggia to water line though worried about excessive water pressure. Any ideas what sort of pressure would be safe for machine? I would like to avoid floating valve in tank and would prefer fresh water straight from pipeline. Thinking about reverse osmosis filter before it too and drain off from drip tray to the waste.
I don't think the Gaggia is plumbable without some serious retrofitting to deal with the water pressure. But I don't know.
LMWDP #603