First Aid: Grinders & Scales

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Grinders are the underrated workhorses of your setup — and most “defects” come down to cleaning, the zero point or simply new beans. Here are the most common problems with grinders and barista scales, with safe steps that follow the manufacturers’ own guidelines: Varia, Weber Workshops, Comandante, Option-O, Eureka and Acaia.

1. “The espresso suddenly runs completely differently than yesterday”

Most common reason: new or older beans — not a defect.

Try this first:

1. Check the bean age: freshly roasted needs a finer setting, older beans need coarser.
2. Adjust the grind size in small steps — one change per attempt, judged by weight and taste.
3. Note a reference value for each bean (clicks/scale).
4. Clear fines from the exit and chamber with a brush and bellows.

Sources: Comandante — FAQ · Varia — VS3 Manual (PDF)

Stop line: No teardown “on suspicion”, no work on the motor.

Go deeper: Grinder Lab · Supplies: brush & bellows in the grinder accessories

2. “The grinder is clogged — almost nothing comes out, then clumps”

1. Unplug the power cord, empty the bean hopper.
2. Clear the exit chute from the outside with a brush and vacuum cleaner.
3. Varia: check whether the setting is in the locked 0–1 range — set it coarser.
4. Work the bellows several times, start a test grind coarser, then go finer step by step.

Source: Varia — VS3 Manual (“blocked grind chamber”) · Video: Varia — VS3 Gen 2 Deep Cleaning (official channel) · Eureka doesn’t document this publicly — our steps apply by analogy; when in doubt, get in touch.

Stop line: Going into the Eureka grinding chamber beyond the accessible chute cleaning = a service case.

Supplies: grinder cleaner & brushes (Cleaning)

3. “After cleaning, no setting is right anymore”

1. Varia: turn the hopper clockwise all the way to the stop past “0”, then back to “0” — that’s the new zero point.
2. Comandante: zero = the first step at which the horizontally held crank no longer drops on its own; count the clicks from there.
3. Option-O: after a burr change, run the zero calibration following the official video.
4. Note new reference values — the first grinds are a break-in phase.

Sources: Varia — Manual (calibration) · Option-O — User Guides · Videos: Varia — VS3 Gen 2 Calibration · Option-O — P80 Zero Calibration

Stop line: No disassembly beyond the manual’s steps (bearing seat, motor shaft); never force the burr carrier into alignment.

4. “The dose fluctuates — old leftovers from yesterday come out with it”

1. Work the bellows after every grind — it’s part of the single-dose workflow.
2. Weber EG-1: take off the magnetic caps, wipe out the grinding chamber — a 30-second routine according to Weber, ideal at every bean change.
3. Brush and vacuum the exit and chamber weekly.
4. Compare the dose in and out (e.g. 18 g in → 18 g out).

Sources: Weber Workshops — EG-1 Cleaning · Weber — KEY Manual · Video: Weber — EG-1 Daily Cleaning (official channel)

Stop line: Wiper system and bearings only as far as opening the magnetic caps; electrics off-limits.

Supplies: dosing cups & bellows in the barista accessories · Puck Prep Workshop

5. “The coffee flies everywhere and sticks to the cup” (static)

From our own practice — hardly any manufacturer documents it officially:

1. RDT: 1–2 drops of water on the beans before grinding — with a spray bottle or the back of a damp spoon. Never spray into a running grinder.
2. Use a metal catch cup instead of plastic.
3. Let the cup sit briefly after grinding, then tap it.
4. Clean the exit regularly — fines make static worse. Dry winter air indoors in Switzerland makes it worse still.

Stop line: No water in the hopper or chamber, no anti-static modifications to the electrics.

Supplies: metal dosing cups (Varia/Normcore) in the barista accessories

6. “The grinder won’t start anymore — or stops halfway through grinding”

1. Switch off immediately, unplug the power cord, remove the beans.
2. Open the grinding chamber only via the officially approved route (Varia: manual, disassembly section) and remove foreign objects — usually a small stone.
3. Vacuum out the chamber, choose a coarser setting, test again.
4. Cross-check the socket and cable with another device.
5. If the motor still won’t start: service — don’t keep experimenting.

Source: Varia — Manual (foreign material)

Absolute limit: Motor, capacitor, circuit board, power supply — never yourself. In the event of stone damage, we’ll check the burrs at the same time.

Request service & repairs

7. “The Comandante turns stiffly, grinds harshly — or the clicks confuse me”

1. With daily use, disassemble and clean weekly with a brush/compressed air — explicitly intended by the manufacturer.
2. Rinsing with water is allowed — but never soak, never a dishwasher, and dry all parts completely. Never wet-clean the Ironheart steel burr set (not stainless).
3. Find the zero point: hold the grinder horizontally — the first step at which the crank no longer drops; count the clicks from there.
4. A little play in the crank at the top is by design — not a fault.

Source: Comandante — FAQ · Video: Comandante — How-To Care & Clean C40 (official channel)

Stop line: Never oil or grease the axle and bearing; a bent axle = service.

Spare parts & Red Clix: Comandante accessories · hand grinders

8. “The Acaia won’t connect to the app — or the firmware update hangs”

1. Switch on the scale, update the app and your smartphone’s operating system.
2. Close all other coffee apps — the scale holds only one Bluetooth connection.
3. Android: enable location services; turn Bluetooth off and back on, hold the phone close to the scale.
4. Stuck update: quit the updater app, disconnect and reconnect USB power, soft-reset, restart the update.

Sources: Acaia — Scale doesn't connect · Acaia — Firmware update failed

Stop line: Never open the scale.

9. “The Acaia switches off mid-shot — or doesn’t charge properly”

1. Adjust the sleep/auto-off timer in the settings or via the app (Lunar: 5 to 60 minutes or Off).
2. Check the charging indicator (Lunar: lightning symbol bottom left; Pearl S: orange lightning top left).
3. Test the cable with another device — faulty cables are the most common cause.
4. Let a hot scale cool down first — the charging protection blocks charging when it’s warm.
5. Fully charge the battery from time to time, don’t store it empty for months.

Sources: Acaia — Lunar Manual (German, PDF) · Acaia — Charging

Stop line: Don’t replace the battery yourself, don’t open the housing.

Scales & accessories: barista scales

10. “The display jumps or drifts — the scale no longer weighs accurately”

1. Place it on a stable, level, vibration-free surface; eliminate drafts and fans.
2. Lunar: check the base alignment — slightly loosen the hex screws and create an even gap between base and pan.
3. Pearl: remove any trapped bits of transport foam between base and housing.
4. Calibrate: weigh-only mode, press the T button 6–7× quickly until “CAL”, place the 100 g calibration weight in the centre.

Sources: Acaia — Numbers jumping · Acaia — Calibration guide · Video: Acaia — Pearl S Smart Calibration (official channel)

Stop line: Never touch or adjust the load cell; after a drop or overload = support.

Order number: #
Device (brand + model):
Serial number (see type plate):
Purchased on:
Problem since:

What exactly happens:

What I have already tried (steps from the First Aid page):

Attachments: photo of the type plate / photo or video of the problem

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