Quick answers to the most common Z2 questions about zeroing, alignment, burrs, retention, cleaning, and grind settings. Each answer links to a full step-by-step guide. These answers are for the Z2. Z1 owners, see Z1 Quick Answers.
User manual and videos
User manual: view the Z2 user manual at https://zerno.co/pages/knowledge-center.
| Video | What it covers |
|---|---|
| Setting the zero point on the Z2 | Rezeroing after cleaning or a burr swap |
| Installing burrs on the Z2 | Burr swaps |
| What a normal chirp sounds like | Telling a true chirp from false chirp |
| False chirp phenomenon | What false chirp is and how to clear it |
| Recalibrating the Z2 motor | RPM knob not working or clicking at startup |
How do I set (calibrate) my zero point?
Your Z2 arrives with a set zero point and is ready to use. Zeroing the dial needs to be done after a burr swap, because different burr sets have slightly different thicknesses.
- Remove the wood accent piece from your front assembly.
- Loosen the knob by 1 to 2 full turns, then turn the grinder switch on.
- Begin tightening the knob until you hear the first burr chirp, then promptly turn the grinder switch off. Running your grinder for a prolonged amount of time while the burrs are touching can wear out the burrs and damage your grinder.
- Using the 2.5mm screwdriver, hold the knob with one hand and loosen the center screw. 1 to 2 full turns should be enough. Do not remove the screw. The micron dial, located behind the knob, should now move freely and independently of the adjustment knob.
- Set the dial to 0 with one hand while holding the knob with the other, then tighten the center screw until snug (but not overtightened).
- Replace the wood insert.
Important: make sure your burrs are not touching before turning the grinder on. We recommend turning the dial a full turn before turning on and verifying your zero point calibration.
Video: setting the zero point on the Z2. Full guide: Setting the Zero Point on Your Z2.
Do you calibrate the Z2 based on first chirp or burr lock?
For safety, we calibrate based on first chirp.
What is the false chirp phenomenon?
Sometimes grind accumulation on the surface of the burrs causes a false chirp: a sound that mimics the burrs touching, along with noticeable dial resistance when you try to make a grind adjustment. It is most noticeable in burr sets that have polishing flats. Watch the false chirp phenomenon video for visual instructions. Full guide: Troubleshooting: False Chirp and Zero Point Shift on the Z2.
How do I swap between burr sets?
Our blind burr design allows for easy swapping using the magnetic burr pull tools. After using the pull tools to remove the installed burr set, use the cleaning brush included with your grinder to remove any leftover grounds before installing the new burr set. Your service kit includes the pins and screws for other burr styles.
Video: installing burrs on the Z2. Full guide: Changing Burrs on Your Z2. Burr stuck? See Troubleshooting: Stuck Burr, Tapping Sounds, and Stuck Beans on the Z2. Need a replacement screw? See Replacement Screws for Your Z2.
How much retention is expected, and how do I minimize it?
It is normal to see about 0.1 to 0.2g of retention on any given grind.
Retention can be caused by many factors, the two most common being environment and beans. To minimize it:
- Before grinding: use your RDT bottle to spray your beans with water 1 to 2 times.
- After grinding: tap the top of the open funnel with the palm of your hand to clear leftover grounds. The Z2 also has Purge Mode and a stainless steel knocker chute.
Full guide: Purge Mode, the Chute Knocker, and Reducing Retention on Your Z2.
How do I adjust my grind settings?
As a general best practice, make adjustments while the grinder is running so no particles get caught between the burrs. You may hear short chirps while adjusting (see the false chirp answer above). Start at a coarser setting and work finer, since grinding too fine can make cleanup harder.
Recommended starting points: espresso 200µm, pour over 600µm. Full ranges, RPM tips, and dialing-in help: Z2 Grind Settings and RPM Guide.
Are there maintenance tips for prolonging the life of my grinder?
We recommend disassembling the grinder about every 50 uses, or as needed. This includes brushing the burr carrier to remove loose grounds, reseating the burrs, and resetting your zero point. We recommend hand-washing all accessories and grinder components to protect the materials, especially the magnetic components.
How do I clean the grinder?
Cleaning is best done by removing the internal components of the grind chamber and using the brush included with your order. Step-by-step instructions for opening and closing the Z2: Opening, Cleaning, and Closing Your Z2.
What should I do if my grinder is making unusual noises?
Many Z2 sounds are normal. For example, a whoosh or low-pitched hum at higher RPM, especially with the funnel cap off, is just the wipers moving air to push grounds out; check Is This Normal? Common Z2 Questions From New Owners first. For shaking, stalls, or a dead RPM knob, see Vibration or Shaking on the Z2, Z2 Stopped, Stalled, or Shut Off, and RPM Knob Not Working or Clicking. In the event of a stall, or anything else related to the performance of your grinder, contact us at info@zerno.co and we will work with you to diagnose and resolve the issue. A short video of the sound helps us a lot.
More Z2 guides
Getting Started With Your Z2 | Choosing Burrs for Your Z2 | Z2 Specs