Espresso shot suddenly stops flowing?

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Valo_Soul

#1: Post by Valo_Soul »

This evening I had a weird phenomenon I've never encountered before. My shot was flowing beautifully up to about 19g (from 18g in an 18g VST), and then the flow stopped... dead... the pump was still engaged on my Breville 920XL... just no more espresso. The gauge was still at or even just slightly above 9 Bar. Is this uncommon? Could it have somehow choked the machine mid-way through the extraction? I'm very confused and hoping there's nothing wrong with my new machine (replaced under warranty).

I just tested it again, pulling two more shots. It did it again, both times. The last shot I even coarsened up the grind a good bit. The shot started by hitting around 8 bar... then climbed and climbed until it choked and stopped itself. What the heck is going on?

I tried pulling another shot with just water, no coffee, using the pressurized basket. It hits around 6.5-7 bar and holds rock steady.... so... this is possibly something wrong with my grinder all of a sudden? :(

I also now pulled a shot with a VERY coarse grind... it sprayed alllllll over my counter, channeling everywhere.. and then the pressure went up and up and up and choked itself again, even with that coarse grind.

Valo_Soul

#2: Post by Valo_Soul »

Hello all - I received a replacement, brand new in the retail box Breville Dual Boiler last month. Mine was under warranty and it was suffering the usual steam wand leak and was making some odd noises while heating.

The new machine was great, and then last night, sadness struck again.

Essentially I'm suddenly getting the opposite effect of what is "normal" in espresso extraction. Rather than seeing the pressure decrease throughout extraction as the puck erodes, it is increasing. Increasing to the point that it ends up choking itself and stopping the flow of espresso entirely. It's very odd.

I'm achieving a nice smooth flow rate, maybe up to about 18-20g in the cup from an 18g dose... floating around 8.5 to 9 bar the entire time, and then it suddenly creeps up and up, out of nowhere, and suddenly chokes at 9.5 bar, and the espresso stops flowing. I've never seen anything like it, and it just started happening out of nowhere.

I've now tried grinding the coffee on my Eureka Atom as well as my Smart Grinder Pro. This issue occurs with both, leading me to realize it simply must be a machine issue. I've also just now noticed a small pool of water on the counter, towards the left side of the machine.

OPV issue? Solenoid? No idea. Any thoughts? :(. Perhaps Breville will have to replace my machine again.

symbology

#3: Post by symbology »

This is a bummer.

You really should pull the cover off and take a look. You have water on the counter and that has to be coming from somewhere. Identify the source of the water and you probably identify your issue as well.

pcrussell50

#4: Post by pcrussell50 »

In a normal puck, the pressure would decline as the puck erodes while the pump is trying to maintain steady flow (it's cutting back this flow in the final third that is a useful technique for improving shots, btw). If the pressure rises all the way until it is bouncing off the OPV (literally, there is a spring inside it), then there has to be some obstruction. I haven't got the vaguest idea what this is. First I've ever heard of this one. So agreed. It's time to take look under the hood. They still owe you a working machine, but for your own edification (and ours if you will share), if you are willing, take off the top cover (prop it up so you don't strain the wires) and pull another shot and see if you can see what is up. The water path is from the top OPV, through the steam boiler, up and out again to the brew boiler, from there to just below the solenoid in the back of the group complex. Wiggle the plastic tubes while this is happening and see what you can see. Something is choking off the flown and driving up the pressure at the OPV (and forcing a leak). This is a new one.

-Peter
LMWDP #553

Valo_Soul

#5: Post by Valo_Soul »

Essentially I'm suddenly getting the opposite effect of what is "normal" in espresso extraction. Rather than seeing the pressure decrease throughout extraction as the puck erodes, it is increasing. Increasing to the point that it ends up choking itself... every single time. It's very odd. I'm getting a nice smooth flow rate, maybe up to about 18-20g in the cup (from an 18g dose)... holding steady around 8.5 to 9 bar, and then it creeps up and up, out of nowhere, and suddenly chokes and completely stops flowing. I've never seen anything like it, and it just started happening out of nowhere a few days ago. It stops itself before I can even reach a 2:1 ratio, and it behaves the same way every time now.

I even went so far as to grind incredibly coarse, causing a huge gusher... and even that suddenly went up up up to 9.5 bar and choked. It makes no sense.

Nobody I've spoken to has ever heard of something like this. I can't find any leaks, and I've even taken the top off the machine and haven't seen any strange behaviour. The machine is only one month old. Awaiting Breville's advice, but their email responses have been incredible slow.

John_Doe

#6: Post by John_Doe »

Say it ain't so as the BDB is supposed to be phenomenal... well apparently not, but surely somebody here will eventually chime in to help.

symbology

#7: Post by symbology »

You had already posted this in another thread and you were offered some suggestions. Have you looked into this at all? Have you pulled the cover off? Figure out where that pool of water came from?

Sorry that this has happened and hope you get it figured out soon.

symbology

#8: Post by symbology »

John_Doe wrote:Say it ain't so as the BDB is supposed to be phenomenal... well apparently not, but surely somebody here will eventually chime in to help.
Phenomenal, well yes.. Perfect, well no.

While it is true the chassis on this machine is not as robust as others, and a few of the internal components are of lesser quality compared to some others. The feature set and abilities of this machine are out of this world for a machine at this price point. I just paid $1K for mine brand new.

With the built in preinfusion abilities I am able to pull off extractions that I never would have been able to on any of my previous machines (this is my 6th). Some of which I paid twice as much for. To me that is phenomenal, really.

I cannot see myself ever owning a machine that does not have similar capabilities. I am talking about a stock BDB.

User avatar
HB
Admin

#9: Post by HB »

Valo_Soul wrote:Hello all - I received a replacement, brand new in the retail box Breville Dual Boiler last month...
Valo_Soul wrote:This evening I had a weird phenomenon I've never encountered before...
Valo_Soul wrote:Essentially I'm suddenly getting the opposite effect of what is "normal" in espresso extraction...
FYI, I merged your two threads since they appear to be closely related as well as the same question in another thread. For future reference, please avoid reposting the same question in multiple threads; it confuses readers and those who are trying to respond to your query.
Dan Kehn

Valo_Soul

#10: Post by Valo_Soul »

symbology wrote:You had already posted this in another thread and you were offered some suggestions. Have you looked into this at all? Have you pulled the cover off? Figure out where that pool of water came from?

Sorry that this has happened and hope you get it figured out soon.

Yes, as I mention in the post above, I have taken the cover off and I don't see anything obvious happening :(

I also cannot see any source of a leak, but in my recent testing as of yesterday, there was no pool beside the machine, strangely. It still completely choked during extraction, before I could reach my 2:1 ratio.

No idea what to do or what is causing this.