High pressure channeling with Breville 920XL

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Latte
Posts: 4
Joined: 5 years ago

#1: Post by Latte »

I purchased one of the first breville 900 XL machines in late 2010. The machine has been replaced many times under warranty. I now have a 920 XL. For many years I used the Barratza Vario grinder. As many have described the importance of the grinder I decided to upgrade my grinder first to the Ceado E37s and plan to upgrade my espresso machine probably to an ECM synchronika some time in the future. . My shots were pretty well dialed in with the old grinder. With the new grinder I'm finding that I am able to get decent shots using about 17 g of intelligentsia black cat coffee, 1.5 ounces in 25 to 30 seconds. I'm getting good looking shots with my bottomless portafilter only if I keep the pressure low throughout the shot.I do this by holding down the single shot button throughout the extraction. The pressure gauge reads about three bars throughout the extraction . If I release the button and go to full 10 bar pressure I find I get a gusher with lots of channeling and a poor taste. The result with the low pressure technique seems good to me but I am wondering what is wrong and why I can't get a decent extraction with high pressure. Anyone have any insights. Perhaps my 920 XL is starting to fail and the pressure is not accurate on the gauge.

mrjag
Posts: 343
Joined: 9 years ago

#2: Post by mrjag »

Test your pressure with the blind filter insert. It should top out around 10-10.5 bar. If it's higher than 10.5 (or lower then 9 bar) then you might want to adjust your OPV valve. If it's within parameters then the grinder is the next likely culprit.

Higher pressure requires a finer grind. Have you tried tightening the grind setting until it stops gushing at 9-10 bar extractions?

User avatar
iploya
Posts: 705
Joined: 12 years ago

#3: Post by iploya »

I've been using the 920XL for a few years and don't have that problem. I don't know if you are counting the 7s default pre-infusion, but 25-30s at that brew ratio is in the ballpark for what it should be at the full 9 bar of pressure. So, I concur with mrjag, it seems most likely that you are not grinding fine enough. Unless there is something else way off (like major clumping or not using your tamp).

Latte (original poster)
Posts: 4
Joined: 5 years ago

#4: Post by Latte (original poster) »

Perhaps I am not grinding fine enough. I will change my setting and post a follow up. Thanks for the advice.

pcrussell50
Posts: 4010
Joined: 15 years ago

#5: Post by pcrussell50 »

I have one of the very first Varios and it grinds easily and beautifully fine enough to go all the way to choking my BDB, even with the Slayer mod and long slow pre infusions. So your Ceado ought to be able to do the same, I expect.

OT, but as a collector of BDB failure modes information, I'd be curious to hear from you what failures caused your "many times under warranty" machines. You can PM me or make a post about it in the "Five years on" thread in the "Machines" section. I (the community) would like to know if you had any new or unique things that we don't already know how to fix ourselves.

-Peter
LMWDP #553

Latte (original poster)
Posts: 4
Joined: 5 years ago

#6: Post by Latte (original poster) »

Grinding finer is the answer. I have been able to get nice shots at full pressure (about 9.5 bar). My Pressure goes to 10 with the blind portafilter. I increased my dose to 18 grams. The taste is much richer. Previously I was essentially making strong drip coffee. Thanks for pointing me in the right direction. I guess when I got such a nice looking shot with the blind porta filter I was afraid to change the settings.

I have had a problem where I get a paradoxical effect where I grind finer and get a faster extraction. I believe this is due to channeling. I have mostly resolved this issue by changing my distribution technique. I now grind directly into the basket, weigh the coffee in the basket and gently tap the sides to settle the coffee, put the basket back in the portafilter and then tamp. I have had some problems lately making my tamp totally level. Does anyone know of a device to keep the breville naked portafilter level while tamping? I know ECM makes one but I'm not sure it is compatible. The coffee i am making now with the breville has been so good I think I will hold off on a new machine such as the synchronica for now.

As far as problems with the breville it is hard to remember all the issues since 2010 but I will try. Initially it was just a miscalibrated opv. I had a problem with sudden complete loss of pressure. The hot water dispenser on all the machines I've had has leaked for sometime after using it. I rarely use it and it's not much of a problem. More recently I got a descale warning on the 900 and sent the machine back to breville, paid $250.00 and they sent me a 920 back. Shortly after the new warranty for the 920 expired I got a descale warning. I descaled the machine myself but the descale warning would not go away. I repeated the descale process a couple of times in an attempt to get rid of the warning and eventually the machine developed a massive leak with water all over the counter. I called Breville and they again replaced the machine for free even though it was beyond the warranty. I would hesitate to descale the machine again as that seemed to result in the leak. I now have a whole house water softening filter system so hopefully scale will be a non-issue.

Thanks again for your help.

pcrussell50
Posts: 4010
Joined: 15 years ago

#7: Post by pcrussell50 »

Latte wrote: I have had some problems lately making my tamp totally level. Does anyone know of a device to keep the breville naked portafilter level while tamping?
I use an old ice hockey puck I got at a San Diego Gulls game back when I was in college. It's about perfect for tamping. Credit due... I got the idea from one of the old legends here at HB a few years back.[/quote]

Thanks for your history. I have always thought it best to do what they do in the shops and what La Marzocco recommends for their home machines, which is to use basically scale-free water. I never got the descale message on a -900, one of which I had for a six year run, before it stopped pre infusing. I do the same with the -920, and have not gotten the descale message in the nine months I've had it. I do a couple-three factory resets every month or so, setting the hardness to as low as possible, "1". I don't know if that is keeping me from getting the message or not. And when I do get it, I will attempt three factory resets again, and see if I can make it go away, without actually doing the descale.

-Peter
LMWDP #553

mrjag
Posts: 343
Joined: 9 years ago

#8: Post by mrjag »

I used a part that I recycled from an aeropress (https://www.amazon.com/South-Street-Des ... 00M1X9852/). Its just the right height to hold it level with the handle on the counter.