If your Breville Barista Express grinder is not working, match the sound to the fault before trying to clear it. Flashing FILTER SIZE lights usually mean the bean hopper is not locked correctly. A motor that runs but produces no grounds points to an empty hopper, a blocked grinder chamber or chute, or moisture in the grinder. Humming, clicking, stalling or a new loud noise calls for an immediate stop and a check for a blockage or foreign object. Start with the normal dry-cleaning procedure; use the manual’s advanced cleaning sequence only for a confirmed blockage between the burrs and the outlet.
This guide covers the Breville Barista Express BES870 series, including the BES870XL sold in North America. It does not cover the Barista Express Impress BES876, which uses different controls and grinder features.
First confirm that the fault is actually on the grinder side. If the machine dispenses a normal dose of grounds but the espresso gauge is too low or too high, or water will not pass through the puck, use the Barista Express pressure troubleshooting guide instead.
Safety first: The burrs are extremely sharp. Switch the machine off and unplug it before removing the hopper or burrs, and keep fingers, hands, hair, clothing and utensils away from the hopper during operation. Never bypass the hopper interlock or grinding activation switch. Do not open the outer housing or attempt internal motor, gear, clutch or wiring repairs.
Quick diagnosis: what the grinder is doing
| Symptom | Most useful first conclusion | Next step |
|---|---|---|
| FILTER SIZE lights are flashing | The hopper is not attached or locked correctly | Remove debris, then reinstall and fully lock the hopper |
| The machine responds, but the grinder is silent | The hopper interlock, activation method, thermal cutout or an internal fault may be involved | Check the hopper and activation test, then allow a hot machine to cool |
| The motor runs, but no grounds come out | The hopper may be empty, or the chamber or chute may be blocked or damp | Check the beans, then clean the burrs and chute |
| The grinder hums, clicks or stalls | The burrs may be obstructed | Stop immediately, unplug and inspect for a blockage or foreign object |
| The grinder suddenly makes a loud noise | Breville lists a blockage or foreign object as the likely cause | Stop and clean before testing again |
| The dose is consistently too small or too large | The FILTER SIZE or GRIND AMOUNT setting may not match the basket and grind size | Check the selected basket and adjust the amount |
| The dose changed suddenly without a setting change | Oil buildup, a partial chute blockage, moisture or incorrect reassembly may be restricting output | Clean, dry and check that the upper burr and hopper are locked |
Run this five-minute grinder test first
- Check the rest of the machine. Switch it on and wait until the POWER light stops flashing. If the entire machine is unresponsive rather than just the grinder, follow the complete Barista Express BES870 troubleshooting guide.
- Read the FILTER SIZE lights. If they flash, the machine is identifying an incorrectly attached hopper. Do not treat that warning as a failed motor.
- Check the hopper. It must be fully seated, turned to the locked position, filled with fresh, dry coffee beans and covered with its lid.
- Use an empty portafilter for the test. Fit the correct basket, select SINGLE or DOUBLE with the FILTER SIZE button and insert the portafilter into the grinding cradle.
- Test automatic dosing once. Push and release the portafilter to engage the grinding activation switch. The grinder should start and then stop automatically.
- Stop if the sound is abnormal. Do not keep cycling a grinder that hums, clicks, stalls or makes a new loud scraping or knocking noise. Switch off and unplug it before inspection.
The result of that one controlled test determines the correct branch below. If the sound is abnormal, do not repeat the test until you have inspected and cleaned the grinder.
What to check when the grinder is completely silent
If the espresso controls work but pressing the portafilter produces no grinder sound, begin with the two external conditions that allow the BES870 grinder to operate: a locked hopper and correct contact with the grinding activation switch.
- Reseat the hopper. Switch off and unplug the machine. Unlock and remove the hopper, clear loose beans or grounds from its locking area, then reinstall it and turn it fully to LOCK.
- Check the indicator again. Switch the machine back on. If the FILTER SIZE lights still flash, the hopper is still not correctly attached; do not bypass its safety interlock.
- Engage the switch as designed. Insert the portafilter squarely into the grinding cradle. Push and release it for automatic dosing. To test manual dosing, push and hold it briefly; releasing it should stop the grinder.
- Allow for thermal protection. If the machine stopped during or after heavy use, press POWER to switch it off, unplug it and let it cool for 30–60 minutes. Breville says the safety thermal cutout can activate when the pump or grinder overheats.
If the hopper locks without flashing lights, the rest of the machine works and both activation methods leave the grinder silent after the cooling period, there is no further external control to reset. Arrange service rather than opening the case or trying to bridge the interlock or activation switch.
What to do when the motor runs but no grounds come out
A spinning motor with an empty portafilter does not automatically mean the motor has failed. The BES870 manual lists three direct causes: no beans in the hopper, a blocked grinder chamber or chute, and water or moisture in the chamber or chute.
- Confirm that beans are present. Use fresh, dry beans and make sure the hopper is fully locked so beans can feed toward the burrs.
- Look for an immediate obstruction. Switch off and unplug the machine before removing the hopper. Check the beans and visible top of the grinder for debris or a foreign object, but do not put fingers into the burrs.
- Perform the normal burr cleaning below. Oil buildup can impede performance, while compacted grounds can block the path to the outlet.
- Keep the grinder dry. If moisture entered the chamber or chute, do not reassemble and test until every grinder part is thoroughly dry.
- Escalate only if needed. If normal cleaning does not open the chute, use the manual’s advanced cleaning sequence for a confirmed internal blockage. Do not improvise deeper disassembly.
How to clear a jammed Barista Express grinder safely
This is the normal owner-cleaning sequence shown by Breville. It removes oil buildup without taking out the lower burr assembly.
- Empty the hopper. Unlock and remove it, pour out the beans, then replace and lock the empty hopper with its lid fitted.
- Run the grinder empty once. This clears loose beans and grounds that remain between the burrs. Do this only with the hopper correctly installed and the lid in place.
- Switch off and unplug. Wait for all movement to stop before unlocking and removing the hopper again.
- Remove the upper burr. Raise its wire handle, turn the burr to the unlock position and lift it straight out. Keep your hands away from the sharp cutting edges.
- Brush all three areas. Use the supplied grinder brush on the upper burr, the exposed lower burr and the grind chute. Remove loose coffee and oily residue without pouring water or cleaner into the grinder chamber.
- Reassemble carefully. Align the upper burr, seat it completely and turn it to LOCK. Replace the hopper and turn that fully to LOCK as well.
- Test with a small quantity of beans. Reconnect the machine and run one short dose. Grounds should fall freely and the sound should be steady rather than strained or irregular.
If the upper burr will not sit flat or lock normally, remove it and check the seating area for trapped grounds. Do not force the handle or operate the grinder with a loose burr or unlocked hopper.
Grinder not working after cleaning?
If your Barista Express grinder stopped working immediately after cleaning, recheck the parts you just removed before assuming the motor has failed. Make sure the upper burr is seated flat and locked, the bean hopper is fully turned to LOCK, and the grinder chamber and chute are completely dry. If the FILTER SIZE lights flash after reassembly, the hopper is not attached or locked correctly. If the motor runs but no grounds come out, remove the hopper again and check for trapped grounds, moisture or an incorrectly seated upper burr.
Use advanced cleaning only for a blockage below the burrs
Breville provides a separate advanced procedure only when there is a blockage between the grinding burrs and the grinder outlet. It removes the lower burr, grind fan and washers, so use the illustrated sequence for your exact machine revision rather than relying on memory. In the current U.S. BES870 manual, the order is:
- Switch off and unplug the machine, remove the hopper and set GRIND SIZE to 1.
- Use a 10 mm socket and turn clockwise only to loosen the burr nut, as Breville specifies.
- Set GRIND SIZE to 16, then unlock and remove the upper burr.
- Remove the nut, spring washer and flat washer, followed by the lower burr. Remove the grind fan and its washers with long-nose pliers while preserving their exact order and orientation.
- Use the grinder brush to clean the chute. Clear the grounds exit chute with the brush or a pipe cleaner; do not push an object into hidden machinery.
- Reinstall the washers and grind fan in the illustrated order. Align the lower burr’s cavity with the drive pin, then replace the flat washer and spring washer.
- Tighten the nut counterclockwise, then insert and lock the upper burr.
- Return GRIND SIZE to 5, replace and lock the hopper, and test one short dose.
Check the diagrams and component order in the official U.S. Barista Express BES870 manual before starting. If your controls, grind range or parts differ, use the manual supplied with your machine. Stop and request service if the nut will not release normally, a burr is damaged, a washer is missing or you cannot reassemble every part exactly.
How to handle humming, clicking, stalling or loud noise
A brief change in pitch as beans feed is different from a new loud, repetitive or strained sound. Breville’s troubleshooting table links loud grinder noise to a blockage or foreign object. Humming, clicking or stopping under load should be treated the same way until the burr path has been inspected.
- Release the portafilter to stop manual grinding, or push and release it to cancel an automatic dose.
- Press POWER to switch off the machine and unplug it. Do not test the noise repeatedly.
- Remove and empty the hopper. Inspect the beans and visible grinder area for debris or a foreign object.
- Complete the normal burr-and-chute cleaning. Use the advanced manual procedure only if a blockage remains below the burrs.
- After correct reassembly, make one short test with a small amount of beans. Stop immediately if the noise returns.
A persistent loud noise, a freely spinning motor with no burr movement or repeated stalling after the path is clear can indicate an internal drive problem. The owner check ends there: motor, gear, clutch and wiring diagnosis requires qualified service.
Why the grinder dispenses too little or too much coffee
A repeatable dose that is simply too small or too large is usually an adjustment issue, not a jam. The selected basket, FILTER SIZE setting, grind size and GRIND AMOUNT position all affect what reaches the portafilter.
- Match the filter selection to the basket. Select SINGLE for the 1 CUP basket and DOUBLE for the 2 CUP basket.
- Use the amount dial for dose correction. Breville gives the 3 o’clock position as a starting point. Turn toward MORE or LESS as needed for the current grind size.
- Know which dosing mode you used. Push and release the portafilter for an automatic dose. Push and hold it for manual dosing, then release it at the desired amount.
- Judge the dose after tamping. A freshly ground portafilter can look overfilled because Breville notes that untamped coffee occupies about three times the volume of tamped coffee.
- Clean if the change was sudden. If the dose fell sharply without a control change, inspect for oil buildup, a partial chute blockage, moisture or an upper burr that was not locked correctly after cleaning.
Once the grinder again delivers grounds consistently, change only one setting at a time. Grind size and dose also affect espresso resistance, so use the pressure guide linked above if the remaining symptom is low, high or absent extraction pressure.
What flashing FILTER SIZE lights mean
On the BES870, flashing FILTER SIZE lights specifically indicate that the bean hopper is not attached correctly. Switch off and unplug the machine, remove the hopper, clear beans or grounds from the locking area, then reinstall and turn it completely to LOCK.
If the hopper is the correct part, sits fully down and locks but the lights continue flashing, do not hold down a hidden switch or wedge the mechanism. The interlock is a safety feature; a persistent warning needs Breville or qualified service.
Replace the hopper only if it is missing or its locking tabs, collar or body are physically damaged. A new hopper will not repair a faulty internal safety interlock.
Why output may be poor immediately after cleaning
| After-cleaning symptom | Check before assuming a failure |
|---|---|
| FILTER SIZE lights flash | The hopper is not fully locked |
| Motor spins quickly but few grounds appear | The upper burr may not be seated and locked correctly, or the chute is still blocked |
| Grinder will not turn normally | A burr, washer or grind fan may be misaligned after advanced cleaning |
| Grounds clump or stick | The chamber, chute or burrs may still contain moisture |
| Dose is different but flow is clear | GRIND SIZE or GRIND AMOUNT may have changed during cleaning |
| New scraping or knocking noise | Stop immediately; do not continue with incorrect assembly or a remaining object |
After routine cleaning, the upper burr should sit flat and lock without force. After the advanced procedure, every washer, the grind fan, lower burr, nut and upper burr must be in the exact documented order. Never try to “wear in” a scraping part by running more beans through it.
When to contact Breville or a service provider
- The grinder remains silent although the machine is powered, the hopper is locked, no FILTER SIZE warning is present and the activation test is correct.
- The machine repeatedly triggers thermal protection after a full 30–60 minute cooling period.
- The grinder continues to hum, click, stall or make a loud abnormal noise after the burr path and chute are clear.
- The motor can be heard but the burrs do not move, or the problem returns immediately after correct cleaning.
- The upper burr or hopper will not lock normally, or any burr, washer, grind fan or locking part is damaged or missing.
- Liquid entered the machine, or there is a burned smell, smoke, unusual heat, sparking or a tripped breaker.
- The machine is new or under warranty and the external checks point to a defect.
For maintenance beyond the cleaning procedures in the manual, Breville directs owners to Consumer Support. Do not remove the outer housing to inspect or replace a motor, gearbox, clutch, wiring, capacitor or control board.
Prevent another grinder blockage
- Use fresh, dry coffee beans and keep water away from the hopper, burrs and chute.
- Keep the hopper lid in place whenever the grinder is operating.
- Check beans for debris before filling the hopper.
- Empty the hopper and perform the normal brush-cleaning sequence when output slows, becomes irregular or shows visible oil buildup.
- Make sure the upper burr and hopper are fully locked after every cleaning.
- Stop at the first repeated hum, click, stall or loud abnormal noise instead of forcing another dose.
- Remove unused beans and clean the grinder before storing the machine for an extended period.
Barista Express grinder FAQs
Why are the FILTER SIZE lights flashing?
The bean hopper is not attached correctly. Remove it, clear debris from the locking area, reinstall it and turn it completely to LOCK. Do not bypass the hopper interlock.
Why can I hear the motor but no coffee comes out?
First check that the hopper contains beans. If it does, Breville identifies a blocked chamber or chute, or moisture in those areas, as the main next checks. Empty the grinder, unplug it and follow the normal burr-and-chute cleaning sequence.
Can I wash the Barista Express grinder burrs with water?
Use the dry grinder brush for the installed burrs and chute. The troubleshooting guide treats moisture in the chamber or chute as a cause of no grounds and says the burrs must be thoroughly dry before reassembly. Never pour water or cleaning liquid into the grinder.
Is it normal for the portafilter to look overfilled?
Yes, before tamping. Breville notes that untamped ground coffee occupies about three times the volume of tamped coffee. Judge the level after tamping rather than stopping a normal automatic dose just because the loose mound looks high.
Why did the machine and grinder stop during heavy use?
The safety thermal cutout may have activated because the pump or grinder overheated. Switch the machine off, unplug it and allow it to cool for about 30–60 minutes. Contact Breville if the problem persists or repeatedly returns.
Can I remove the lower burr myself?
The BES870 manual includes lower-burr removal only as an advanced cleaning procedure for a blockage between the burrs and the outlet. Follow the exact illustrated order for your machine, remember that the burrs are extremely sharp and stop if any part does not release or reinstall normally.
Does this guide apply to the Barista Express Impress?
No. This guide is for the Barista Express BES870/BES870XL. The Barista Express Impress BES876 has a different assisted-dosing system and should be diagnosed with its own manual.
The fastest reliable rule is to let the symptom choose the fix: flashing FILTER SIZE lights point to the hopper, silence calls for the interlock and activation checks, normal motor sound with no grounds points to the chamber or chute, and humming or loud noise means stop and inspect for an obstruction. Once grounds dispense normally, treat any remaining espresso-flow or gauge problem as an extraction issue rather than a failed grinder.