Seasoning (also called breaking in) means running coffee through new burrs so they settle in quicker.
Quick answer
Seasoning is optional. Your Z2 makes great coffee right out of the box, and the burrs will season on their own as you use them. If you want to speed things up, grind 500g at a time at about 500µm and 900 RPM, let the Z2 rest 5 to 10 minutes between batches, and repeat until you reach the amount for your burrs below. Then clean the grinder and recheck your zero point.
What does seasoning actually do?
New burrs may carry tiny machining marks or have an uneven friction coefficient from manufacturing. Grinding coffee smooths those marks and lets the burrs settle into their carriers. The result is less shot to shot variation and a more consistent particle distribution.
Do I have to season my burrs?
No. You are more than welcome to:
- Season with use. Brew normally and enjoy watching the burrs improve with every cup. Many owners prefer this.
- Season deliberately. Run inexpensive beans through in batches (steps below) to get past the break-in period quickly, so your good coffee only goes through settled burrs.
Seasoning makes the biggest difference for espresso, where small changes in consistency show up quickly in the cup. It matters most for SSP Lab Sweet, the only cast burr in our 80mm lineup.
Was my Z2 seasoned before it shipped?
No. Every Z2 is tested with a small amount of coffee during quality control, which is why you may find a little residual coffee at unboxing. That is not enough to season the burrs. Any extra burr sets you ordered have not been seasoned at all.
How much coffee do I need?
It depends on your burrs. Most of our 80mm burrs settle quickly. Lab Sweet is cast, and cast burrs take longer to settle because of small variations from the casting process.
| Burrs | Type | Usually settled after |
|---|---|---|
| Core | Machined | 1 to 2kg |
| SSP Ultra Low Fines (ULF) | Machined | 1 to 2kg |
| SSP Brew | Machined | 1 to 2kg |
| SSP Low Uniformity (LU) | Machined | 1 to 2kg |
| SSP Lab Sweet (LS) | Cast | About 5kg, sometimes more |
These are guidelines, not hard limits. You will notice improvement well before you reach them, and some cast sets keep improving past 5kg.
How do I season my burrs?
- Make sure the dial is set above 200µm before you turn the grinder on. Never start the Z2 with the burrs touching. There is no lock at zero, and the dial can turn past it.
- Turn the grinder on (switch up) and set the dial to about 500µm. Always adjust the dial with the grinder running.
- Set the RPM knob to 900 RPM while the grinder is on but before you add beans. Do not change RPM while beans are being ground.
- Feed about 500g of beans through the funnel. Empty the dosing cup as it fills.
- Hold the switch down for 2 to 3 seconds to run Purge Mode and clear the grind chamber. Then turn the grinder off (switch to the middle) and let it rest 5 to 10 minutes.
- Repeat until you reach the amount for your burrs in the table above.
- Unplug the Z2, open it, and brush out the burrs, grind chamber, and chute. See Opening, Cleaning, and Closing Your Z2.
- Recheck your zero point. See Setting the Zero Point on Your Z2.
Why 500µm and 900 RPM?
A medium coarse setting moves coffee through quickly, keeps grounds flowing out of the chute, and creates less heat than fine grinding. 900 RPM balances speed and grind quality, and it is our recommended starting point for everyday grinding too. Seasoning at espresso settings or at extreme RPM is not necessary. For more on how RPM affects the grind, see the Z2 Grind Settings and RPM Guide.
Can the Z2 handle grinding that much coffee?
Yes. The Z2 is designed primarily as a single dose grinder, and we recommend small batches day to day. It handles extended seasoning sessions without issue, and we run long sessions during internal testing. The 5 to 10 minute rest between 500g batches gives the motor and burrs time to cool and supports long term reliability. Avoid running it for hours without breaks.
What beans should I use?
Use beans you would not want to drink anyway: older beans, inexpensive grocery store beans, or seasoning beans sold by some roasters. Save your fresh specialty coffee for after the burrs settle.
Very dark, oily beans will work, but we suggest avoiding them where you can. Oils smear across the burrs during long sessions and make cleanup afterward more difficult.
What do I do before switching to my good coffee?
Brush out the grinder (see the cleaning section below), then run a few grams of your regular coffee through to clear any leftover seasoning grounds before you brew.
I have more than one set of burrs. Do I season each set?
Yes. Seasoning stays with the burr set, not the grinder. Each set needs its own break-in. If you are short on seasoning beans, start with the set you use for espresso (such as Core or Lab Sweet), since that is where seasoning helps most. For burr swap steps, see Changing Burrs on Your Z2.
What is normal while my burrs are seasoning?
Shot times vary from day to day. Some shot to shot variation is expected in the first kilogram or two, even with the same beans, setting, and workflow. It settles as the burrs do.
Your zero point moves slightly. As new burrs settle into their carriers, the zero point can shift by a small amount. That is normal. A human hair is about 100µm thick, so these are very small changes. Recheck your zero point once seasoning is done.
Your espresso setting moves around. Lab Sweet in particular can land anywhere from very fine to fairly coarse for espresso while it seasons. Start coarser and work finer, and expect to adjust a few times.
The dial feels stiff going back to fine settings. After grinding coarse, coffee particles can pack into the flats of the burrs. Turn the grinder on before moving finer and push through gently. See our False Chirp article for more information.
After seasoning, I can't grind fine enough for espresso
This is almost always the false chirp phenomenon, not a problem with the grinder. Fine particles packed into the flats of the burrs make them chirp before they actually touch, so your zero point reads coarser than it really is. Clean the burrs and rezero on a true chirp. See Troubleshooting: False Chirp and Zero Point Shift on the Z2.
Grounds spilled on the stand and scratched it
Seasoning produces a lot of grounds, and loose grounds trapped under the dosing cup can leave swirl marks on the stand. Wipe or vacuum loose grounds off the stand before moving the dosing cup, and keep the foam under the cup clear of grounds. The stand is 304 stainless steel, so light swirl marks buff out with a metal polishing paste or stainless steel cleaner. When you remove the magnetic chute knocker, avoid hitting the stand as you pull it down.
How do I know my burrs are seasoned?
Shots become more consistent from one day to the next, your espresso setting stops drifting, and your zero point holds steady between cleanings.
Do I need to clean the grinder after seasoning?
We recommend it. Seasoning sends a lot of coffee through the grinder, and fines can build up around the burrs. A full cleaning after seasoning gives you a fresh starting point for setting your zero point. Going forward, a cleaning about every 50 uses keeps the Z2 grinding consistently. Between cleanings, Purge Mode and the chute knocker help keep retention low. See Purge Mode, the Chute Knocker, and Reducing Retention on Your Z2.
Still have questions?
If these steps do not work, please contact support at info@zerno.co.
Related
Getting Started With Your Z2 | Choosing Burrs for Your Z2 | Setting the Zero Point on Your Z2 | Z2 Grind Settings and RPM Guide | Changing Burrs on Your Z2 | Opening, Cleaning, and Closing Your Z2 | Purge Mode, the Chute Knocker, and Reducing Retention on Your Z2 | Troubleshooting: False Chirp and Zero Point Shift on the Z2