Seasoning (also called breaking in) means running coffee through new burrs so they settle in quicker.
Quick answer
Seasoning is optional. Your Z1 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, let the Z1 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 seasoned burrs for the most consistent extractions.
Seasoning makes the biggest difference for espresso, where small changes in consistency show up quickly in the cup.
Was my Z1 seasoned before it shipped?
No. Every Z1 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. Machined burrs settle quickly. Cast burrs take longer and vary more from set to set.
| Burrs | Type | Usually settled after |
|---|---|---|
| SSP Unimodal V1 (UMV1) | Machined | 1 to 2kg |
| SSP Multipurpose V2 (MPV2) | Machined | 1 to 2kg |
| SSP High Uniformity (HU) | Machined | 1 to 2kg |
| Mazzer 233M | Machined | 1 to 2kg |
| SSP Cast V2 (CV2) | Cast | About 5kg, sometimes more |
| SSP Cast V3 (CV3) | 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 Z1 with the burrs touching. Doing so blows the internal safety fuse.
- Turn the grinder on and set the dial to about 500µm. Always adjust the dial with the grinder running.
- Feed about 500g of beans through the funnel. Empty the dosing cup as it fills.
- Turn the grinder off and let it rest 5 to 10 minutes.
- Repeat until you reach the amount for your burrs in the table above.
- Unplug the Z1, open it, and brush out the burrs, grind chamber, and chute. See Opening, Cleaning, and Closing Your Z1.
- Recheck your zero point. See Setting the Zero Point on Your Z1.
Why 500µm? Can I season at my espresso setting?
A medium coarse setting moves coffee through quickly, keeps grounds flowing out of the chute, and creates less heat than fine grinding. The finer you go, the more heat builds up during long sessions. Seasoning at espresso settings is not necessary. With burrs that produce a lot of fines, like the HU, coarser settings also help grounds flow out of the chute while the burrs are new.
Can the Z1 handle grinding that much coffee?
Yes. The Z1 is designed as a single dose grinder for home use, and we recommend small batches day to day. It handles seasoning sessions without issue. During long sessions, the burr area heats up more than the motor does, which is why we ask for the 5 to 10 minute rest between 500g batches. 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, since that is where seasoning helps most. For burr swap steps, see Changing Burrs on Your Z1.
My Mazzer burrs feel oily. Is that normal?
Yes. Mazzer burrs arrive with a light coat of food safe storage oil that protects the steel from rust during shipping. Wipe the cutting surfaces with a clean paper towel or cloth before installing them, then grind some coffee through to season them and clear any remaining oil. Do not scrub the back side clean. A very thin layer of oil there helps protect the steel.
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 about 20µm. 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 changes. You may need to adjust your grind setting a few times as the burrs break in.
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. It is most common with the HU and Mazzer 233M burrs, which have large finishing flats. Clean the burrs and rezero on a true chirp. See Troubleshooting: False Chirp and Zero Point Shift on the Z1.
My HU burrs keep clogging
New HU burrs produce a lot of fines, and they can pack into the grind path until the burrs settle. See Troubleshooting: HU Burrs Clogging While They Season (Z1).
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.
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 behind the burrs. Because the Z1 is built with very tight tolerances, that buildup can make the burrs harder to remove later. After seasoning, open the grinder and brush everything out. Going forward, a cleaning about every 50 uses (or every couple of months) keeps burr swaps easy. See Opening, Cleaning, and Closing Your Z1 for more information.
Still have questions?
If these steps do not work, please contact support at info@zerno.co.
Related
Getting Started With Your Z1 | Setting the Zero Point on Your Z1 | Z1 Grind Settings, RDT, and Retention | Changing Burrs on Your Z1 | Opening, Cleaning, and Closing Your Z1 | Troubleshooting: False Chirp and Zero Point Shift on the Z1 | Troubleshooting: HU Burrs Clogging While They Season (Z1)