Breville BCG800XL Smart Grinder Troubleshooting
This guide will help you troubleshooting the most common cause of jamming with the BCG800XL (and BCG800) Smart Grinder from Breville.
Many users of the BCG800XL SmartGrinder experience jamming / clogging and a horrible gear-stripping, clacking sort of sound during use at some point. This is usually due to either a worn out impeller or stripped drive gear.
Here's a 10-second video I recorded of the problem / symptoms.
Symptoms of a worn impeller
The main symptom of a worn impeller is the motor will bog down even at a coarse grind settings (which should be easy on it) and after a few seconds, after too much coffee gets compacted beneath the burrs, it begins making that stripping /clacking sound you hear at the end of the video. When the hopper is empty and no beans are in the burrs, it all sounds great. You can even hear in the video above: The unit starts out sounding normal, but under load, up until the clacking sound. Often, incorrectly, the coffee beans get the blame.
On the other hand, a stripped drive gear will sound bad nearly ALL THE TIME, even with no coffee beans. Each revolution of the damaged gear teeth will make a bad sound. If the teeth are really wrecked, you sometimes won't even get rotation anymore and you'll just hear the motor spin up like a jet engine. Thankfully this failure mode is much less common; typically occurring if you got a rock or pebble jammed in the burrs during grinding.
What does a bad impeller look like?
A good impeller should not be removable without dis-assembly and the tips of the impeller blades should not be visible. If the impeller can be removed just by taking out the lower burr then it definitely needs replacement.
If your impeller is made of stainless steel rather than plastic you likely have a newer model with significant design changes (eg: BCG820). Stainless steel should not wear out and so your problem is elsewhere.
Why does the BCG800 Smart Grinder's impeller matter?
It sits underneath the steel burrs and receives the ground coffee. Its purpose is to push those grounds out the chute that leads to the basket (or espresso portafilter). When the plastic blade fins wear down over time, the grinder begins to clog up because it can't properly expel the grounds anymore. This often gets mistaken for a problem with the main drive gear when a stripping sound comes from a torque limiter mechanism. You can examine your impeller if you simply remove the burrs, and look at the gap between the cylinder wall and the impeller blade tips (See Step #1). If that gap is more than 1 mm, then it's probably worth replacing. If you can take the impeller out without dis-assembly, then it's definitely worth replacing (A good impeller is wider than the hole and can't just come out).
Breville unfortunately doesn't sell parts, so this tutorial has been made possible only recently by 3D printer technology. I've designed an improved impeller for the BCG800XL and made it available here: Shapeways Impeller Source
Here's a quick two minute overview of this replacement part.