Before you start on your journey, watch this video from our Co-Founder, Vel:
Commitment to Quality
All grinders complete a rigorous quality assurance protocol prior to dispatch. As a result, you may see a small amount of coffee grinds in your grinder.
Assembly
Funnel: Use your finger to check and ensure the O-ring is seated. Then, push and twist the funnel until it is properly seated.
Chute: Your magnetic chute is secured in a foam insert inside of your dosing cup. Remove and snap into place underneath the grind chamber.
Burrs: Your burrs will come pre-installed and aligned by our engineering team. For safety, check the zero point to confirm alignment before seasoning your burrs. Set screws are not required for the rotary burrs on any model. Set screws on the stationary side are not required in newer models due to a design update where we upgraded the magnets on the stationary side. If your grinder shipped without screws, this was intentional and means your grinder does not require set screws. To double check, look at the 3 bolts behind the burrs are configured. Bolt @ 12 o’clock mean you have the upgraded magnets and as a result there is no need to use the set screws. Bolt @ 6 o’clock, we recommend using set screws on the stationary side only.
Accessories
Full List
Tools
Our screwdrivers are shipped collapsed to fit in the box for shipping. However, we recommend extending the length. Loosen the set screw on the side of the screwdriver handle with the 2mm hex key included in your order. Extend the shaft until you see the flat spot, and tighten the set screw securely to lock the shaft in place.
Set Screws
Set screws are used to help secure your blind burrs in the burr carrier. Versions of the Z1 delivered after May ’24 include an upgraded high-strength magnet in the carrier which eliminates the need to use set screws. In earlier versions, set screws are required on the stationary burr, and optional on the rotary burr.
Traditional Workflow
Magnetic Portafilter Holder Workflow
Cold vs. Hot Start
The Z1 is designed to safely grind with a hot start or cold start. We recommend experimenting with both and see which works better for your workflow and the beans you are using. Remember to add the cup under the chute when grinding(it is more common than you would think)
Cold Start: Add beans to the hopper, replace the lid, and turn on.
Hot Start: Turn on, add beans to the hopper and replace the lid.
Minimizing Retention
V2 of the Z1 features technology and materials that greatly reduces retention. For any remaining grinds, simply tap the top of the funnel using the palm of your hand.
SAFETY NOTICE
Whenever performing maintenance or anything that requires grinder disassembly/grind chamber access, disconnect the power cord from the outlet and toggle the power switch 2-3 times to account for any remaining charge before removing the cup, chute and funnel from the main assembly. Always use a grounded plug anytime the grinder is in use.
Accessing the grind chamber(see 00:00 of this blind burr install tutorial video)
You can identify the front assembly by the two screws that secure it to the base of the grinder. To remove and access the grind chamber, loosen the 2 visible screws using the provided 2.5mm screwdriver. While supporting the adjustment assembly with one hand, pull the screws to remove. Place your front assembly on a flat surface burr side up.
Seating the front assembly(see 14:35 of the blind burr install tutorial video)
Make sure the outermost ring of the adjustment assembly and grind chamber are clean and free of coffee grounds. Hold the adjustment assembly firmly against the grind chamber with one hand and line up the 2 mounting screws, ensuring that the adjustment assembly is sitting flat and parallel to the grind chamber. Start tightening up one of the side screws. While supporting the adjustment assembly with one hand, gently alternate tightening both sides until they are both sufficiently tight but not overtightened. Ensure surfaces are flat and parallel before plugging in and turning the grinder on.
Installing & swapping burrs
Swapping Medium Feed and Slow Feed Auger
Remove the front assembly to access the grind chamber, and pull to remove the auger assembly. Note that you do not need to remove the burr. Remove the 3 screws from the back of the auger assembly using the 2mm screwdriver included in your toolkit, before pulling to remove the auger and cleaning any leftover grounds from behind the auger assembly. Replace the new auger and use the 2mm screwdriver to replace the screws behind the assembly, making sure that the screws are secure but not over-tightened.
Setting your zero point(See 18:25 of the blind burr install tutorial video)
Your Z1 arrived with a set zero point and ready to use. Zeroing the dial will need to be performed in the event of a burr swap as different burr sets have different dimensions. To set the zero point, start by removing the wood accent piece from your front assembly before turning the grinder switch on and loosening the knob by 1-2 full turns. Then begin tightening the knob until you hear the first burr chirp and promptly turn the grinder switch off.
Using the 2.5mm screwdriver, hold the knob with one hand and loosen the center screw – 1-2 full turns should be sufficient. 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 before tightening the center screw until snug(but not overtightened). Finally, replace the wood insert.
Adjusting your grind
As a general best practice, we recommend making adjustments while the grinder is running to ensure no particles are caught between the burrs while adjusting. You may hear short chirps while adjusting – see the ‘false chirp phenomenon’ portion of the troubleshooting section for more info. When making adjustments, we recommend starting at a higher grind level before dialing in smaller as grinding too fine may make for more difficult clean-up.
Recommended grind settings: Espresso – 200um Pour – Over – 600um
Cleaning
Cleaning is best done by removing the internal components of the grind chamber before using the brush that is included in your order. Removable components include the front assembly, burrs, prebreaker, chute and funnel. During reassembly, it is important to push the prebreaker fully back into the grind shaft while making sure that the prebreaker key is engaged – When done correctly, you should feel a spring action providing resistance. See the section highlighting reseating the front assembly for further reassembly instruction.
Seasoning – Burrs
The Zerno Z1 is designed as a single-dosing grinder for use at home. While the grinder can handle long periods of continuous grinding, we recommend seasoning in small batches for the health and longevity of your Z1.
SSP Burr Recommendation
Amount: 4kg of beans
Grind Setting: 500um
Grind Rate: 500g at a time w/ 5-10 min rest between grind sessions
Seasoning – Prebreaker & Auger
We recommend seasoning with at least 1 kg of beans when introducing a new swappable prebreaker, and can expect performance to continue to improve over time.
General Maintenance – Z1 Grinder
We recommend grinder disassembly every ~50 uses – This includes brushing the burr carrier to remove loose grounds, reseating burrs, and resetting your zero point.
General Maintenance – Accessories
We recommend hand-washing all accessories and grinder components – This protects the integrity of the materials, especially magnetic components.
False Chirp Phenomenon
Sometimes grind accumulation on the surface of the burrs can cause a false chirp phenomenon that produces a sound that mimics burrs touching in addition to notable dial resistance when attempting to make a grind adjustment. This phenomenon is most noticeable in burr sets that have polishing flats, such as the SSP HU blind burrs. The video above addresses the phenomenon along with a quick fix.
Zero Point Shift
There are a couple factors that could potentially contribute to your zero point shifting during use – The most likely cause is under-seasoned burrs, as there is typically some settling that occurs during the first ~5kg of beans. If the issue persists, we recommend removing the front assembly and burrs before reseating and assembly with a grind setting of ~100um. Another contributing factor could be related to the false chirp phenomenon, which is explained in the section above.
Bean Stuck in Auger
There are times where you may notice a bean or two stuck between the entrance of the funnel and the prebreaker assembly. This can be caused by a number of factors including bean type, size, roast level and moisture content. The v3 standard augur introduced a toothed design that largely eliminates the phenomenon, however the occasional stuck bean is the reality for all vertically-driven grinders, and could still happen from time to time. If you do experience a stuck bean, using a chop stick or similar shape rod to push the bean into the prebreaker entryway provides a quick fix.
Bean Popcorning
Popcorning is a phenomenon that is consistent across many single dose grinders, specifically when using our single-channel slow feed auger setup. This can be avoided by slowly introducing beans into the funnel rather than all at once.
Grinder Stall
Always test and pay close attention when using new beans or a new grind setting. If you hear the Z1 struggling, turn it off immediately and try a coarser grind setting.
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 resolve the issue.
Stuck or Stripped Set Screws
If your set screw is stripped or unable to be removed, you may need to use a screw extractor to completely remove from the burr carrier. In this case, we recommend using an M4 or M5 screw extractor from your local hardware store.
