Ben Gottemoller

One other thought also: Check the fineness of the grind. Could it be finer than you had ever gone before? If the grind is ultra-fine, it can become like a paste and clog the grinder that way. If it’s tough to tell by feel or look of the grounds, you can probably tell this way too: Fill your portafilter, grinding by weight (eg: 18g for a double shot). Then tamp normally, and attempt to pull a standard 9-bar shot. If it fails to give more than a trickle then it is probably too fine.

Then it becomes a question of whether the lower burr is too high or the upper burr needs elevation ring adjustment.

Double check that the lower burr is not sitting too high using the images here:

BCG600SIL Dose Control Pro Coffee Grinder - Jamming due to Worn Impeller

Hi David,

Thanks for posting. Any chance this is a really dark roast? These can be super oily and cause issues. I have a writeup on this over on the BCG800 page here:

BCG800XL Grinder Jamming due to Worn Impeller

In that case it’s not static but momentum, since the high amount of coffee oils cause large clumping and these tend to maintain their angular momentum when exiting the chute. In that case water might even make the issue worse. Perhaps try a medium or light roast to evaluate if this idea is on track. Cheers.

Nice job Robco. Good to know some units only have one washer as well. Maybe at the factory Breville varies it based on tolerance stack up. In any event glad you got it all fixed up and enjoy your coffee.

Based on your video there must be a upper burr to lower burr clearance issue. That is definitely the sound of the burrs beginning to touch.

First check the lower burr height relative to the *lip on the drive shaft*. Inspect the picture here for reference to make sure your burr it is not sitting too high:

BCG800XL Grinder Jamming due to Worn Impeller

Next, you can pretty easily just pull the lower burr (just take off the acorn nut and lift the burr). Make sure no grounds or anything got between the impeller and the lower burr. Also make sure at reassembly that the acorn nut is torqued pretty tight. A few flicks of the wrist tightening should get it there.

Once you are confident the lower burr is correct, and if the problem persists, then the problem must be with the upper burr height:

BCG800XL Grinder Jamming due to Worn Impeller

Could the larger gear have gotten rotated out of alignment? It sets the upper burr height.

Hi Greg,

Some users have mentioned tiny plastic nubs that poke out from beneath the stainless steel cladding. I am told those still wear down, but they are so small it is hard to conclude if they actually matter. It might be worth taking a close look at the impeller to see if there is anything noticeable at all.

Hi Peter,

Looking at the photos, the first image stands out due to the large washer. Did the original get lost? I am wondering if it could be a bit thicker, and thus squashing the impeller more than usual when the acorn nut is tight. I also did not see the two washers that normally reside under the impeller. I know you mentioned checking for them so perhaps they are just not in place when the pics were taken. In case it helps I have added a cutaway diagram here with all the parts, showing how they stack up to set the height of the lower burr: BCG800XL Grinder Jamming due to Worn Impeller

Also, if you want you can upload pics to an imgur album here: https://imgur.com/ and then post back the link. I am happy to take a look.

Hi Peter,

If the lower burr height vs the lip on the drive shaft looks correct after double checking, then perhaps the problem is with the upper burr holder. It *must* be the spacing between the burrs, right? Obviously the gear alignment is very important for that spacing, and I believe you could intentionally misalign/rotate the big gear such that the finest setting places the upper burr *lower* for a finer grind, but it would require careful experimenting.

Another thought: Could the upper burr holder be lifting up somehow during grinding? See here: BCG800XL Grinder Jamming due to Worn Impeller

If any radial plastic snaps broke, then the upper burr holder may flex-upwards as the chamber below it fills with grounds. Ditto if the hard to reach screws are too loose. Focus on the upper burr mounting and inspect the gap to the lower burr. Prying on it and see if there is flexing. It’s going to require investigation, however this seems like a good avenue.

Hi Peter, It may be worth double checking that the two washers under the impeller made it back into place. Also, misalignment of the gears in step 8 might cause this.

If necessary, the optional modification here will get you more range to work with: BCG800XL Grinder Jamming due to Worn Impeller

Hi Tim, I believe the stock washers are each 17.53mm outer diameter and about 10.2mm inner diameter. You could probably stray from there slightly to make it easier to find. Thickness is very very thin however and I unfortunately never measured. Rough guess is about 0.1 mm each, and there are two of them. FYI, if you want an easier route, this is my preferred trick for getting finer grinding: BCG800XL Grinder Jamming due to Worn Impeller