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I am getting consistent channelling on my Gaggia Classic at the 12 o'clock position in the basket (see pictures). It's really frustrating and I can't seem to get rid of it.

 

I am dosing 19.5g into an IMS 26.5 basket, and then distributing with a home made WDT tool before tamping.

 

I'm using a bottomless portafilter, and the pour always starts really nicely, coming through evenly with some lovely tiger stripes. This usually lasts about 10 seconds before it blows and gushes out.

 

Has anyone any idea why the channelling always happens at the 12 o'clock position?

 

Thanks

 

IMG_20190327_073349.jpg

IMG_20190326_144513.jpg


Gaggia Classic with MrShades PID, OPV adjusted and Silvia wand added, IMS screen and baskets, bottomless pf; Motta 58.4mm tamper. Brasilia RR55 OD, and MildredM's bar towels

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A clip of the prep and pour is more helpful than post puck

Would be worth establishing if you have enough head room in our basket. So dose your 19.5 g put a 5p coin on top , put in pf. Take out pf, is the coin leaving an indent .

Is the indent we see at 12 o'clock post puck there too ?


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A clip of the prep and pour is more helpful than post puck

Would be worth establishing if you have enough head room in our basket. So dose your 19.5 g put a 5p coin on top , put in pf. Take out pf, is the coin leaving an indent .

Is the indent we see at 12 o'clock post puck there too ?

 

Thanks for the reply. I settled on 19.5g for this particular bean by using the coin check method, and there is no indent in the puck prior to putting the portafilter in and pulling the shot. If I was getting channelling in other places then I would be more worried about my prep, but it is always at the 12 o'clock position.


Gaggia Classic with MrShades PID, OPV adjusted and Silvia wand added, IMS screen and baskets, bottomless pf; Motta 58.4mm tamper. Brasilia RR55 OD, and MildredM's bar towels

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Looking at the deep rim around the puck you may have too much coffee in. Try a coin test 5p or 1p not leaving an impression on a tamped puck. If there is too lightly space when the grinds expand they get compressed even more. A little of that may help actually but too much and the pressure will find a weak spot or choke the machine.

 

Also do you need to stir up the grinds ? Some do it as they have read about it but it can make things worse. Light clumps that break up easily aren't a problem. Sufficient tamping will over ride them. Light tamping without some associated number with it can also cause grief.

 

I'm assuming that the tamp is reasonably level. If always low on that side ...............

 

John

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In Use Sage DB+IMS Shower Screen, Niche. Profitec T64. Others Sage BE, Mazer Mini A, Ceado 37J. Projects Little Gem, Gaggia M7D

:pToo many filter baskets - maybe. For sale when I get round to it. Robur Elect, Ceado 37J, Ascaso i_1,Piccino

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Thanks for the reply. I settled on 19.5g for this particular bean by using the coin check method, and there is no indent in the puck prior to putting the portafilter in and pulling the shot. If I was getting channelling in other places then I would be more worried about my prep, but it is always at the 12 o'clock position.

 

It actually looks like there is channelling all around the perimeter of the puck? So, if your dose weight is OK (20g basket?), you may be way too fine.


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Is the brew head level ? Is the shower screen firmly fixed ? Dosing 19 gm's in a 26 gm basket, is it under-dosed ? too much head space ?

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Is the brew head level ? Is the shower screen firmly fixed ? Dosing 19 gm's in a 26 gm basket, is it under-dosed ? too much head space ?

 

I took the 26.5 to refer to the height of the basket. The rim of the puck looks weird but hard to tell if it sticks out or goes in from the shot also it looks vaguely domed.

 

John

-


In Use Sage DB+IMS Shower Screen, Niche. Profitec T64. Others Sage BE, Mazer Mini A, Ceado 37J. Projects Little Gem, Gaggia M7D

:pToo many filter baskets - maybe. For sale when I get round to it. Robur Elect, Ceado 37J, Ascaso i_1,Piccino

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The OP uses a dosing funnel that sits well into the basket (cheaper on Amazon). Did this start when you used this?

 

John

-


In Use Sage DB+IMS Shower Screen, Niche. Profitec T64. Others Sage BE, Mazer Mini A, Ceado 37J. Projects Little Gem, Gaggia M7D

:pToo many filter baskets - maybe. For sale when I get round to it. Robur Elect, Ceado 37J, Ascaso i_1,Piccino

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Is the brew head level ? Is the shower screen firmly fixed ? Dosing 19 gm's in a 26 gm basket, is it under-dosed ? too much head space ?

 

The 26 refers to the height of the basket, not its capacity. I think this one is 18g - 20g capacity


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From the picture i can tell you are grinding too fine


Gaggia Classic 2010(PID&IMS 200µm shower screen&Brass Dispersion Plate&OPV&Steam Wand Modded) | Kinu M47 V3 | Mazzer Major Electronic 2017Niche Zero | Bottomless Portafilter&VST Ridgeless 15gr and 18gr | Decent Tamper V2 | MouMou 58mm Distribution Tool | 2X 64oz Airscapes & CoffeeVac

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Thanks for the suggestions everyone.

 

I'll have a play over the weekend and see how it goes


Gaggia Classic with MrShades PID, OPV adjusted and Silvia wand added, IMS screen and baskets, bottomless pf; Motta 58.4mm tamper. Brasilia RR55 OD, and MildredM's bar towels

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