What grind setting should I use for cold brew on the Zerno Z1?

Start at 960–1100 for a light roast, 1030–1170 for a medium roast and 1100–1240 for a dark roast.

How long should I steep cold brew ground on the Zerno Z1?

18–22 hours in the fridge for a light roast, 14–18 for medium and 10–14 for dark. On the counter it goes faster: 12–14, 9–12 and 7–9 hours.

What should the grounds look like?

Coarse. About the size of coarse sea salt for a light roast, coarse kosher salt for medium and raw sugar for dark.

Electric grinder

Cold brew grind setting for the Zerno Z1

960–1100

That is where to start with a light roast. It should come out looking like coarse sea salt. Medium roasts go to 1030–1170 and dark roasts to 1100–1240.

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Zerno Z1, set for a light roast

The setting, by roast

Lighter roasts are harder to pull flavor out of, so they grind a little finer and steep longer. Darker roasts go the other way. The dial runs from 0 to 1400.

Roast	Setting	Looks like	Steep in the fridge
Light roast	960–1100	coarse sea salt	18–22 h
Medium roast	1030–1170	coarse kosher salt	14–18 h
Dark roast	1100–1240	raw sugar	10–14 h

Where the number comes from

Nobody has published a cold brew number for this grinder that we could find, so treat 1100 for a medium roast as a place to start.

Maker’s guidance: zerno.co

If you changed the burrs

Different burrs cut differently at the same number. Here is where each set starts.

Burr set	Light	Medium	Dark
SSP Multipurpose V2 64mmCommon all-rounder choice at checkout	960–1100	1030–1170	1100–1240
SSP High Uniformity 64mmVery narrow particle-size distribution -- same dial reading, noticeably less fines/silt in cold brew	960–1100	1030–1170	1100–1240
SSP Unimodal Brew 64mmBrew/filter-tuned unimodal cut -- cleaner cold brew at the same micron reading	960–1100	1030–1170	1100–1240
Mazzer 233M 64mmTraditional flat-burr flavor profile, more body than SSP options at the same setting	960–1100	1030–1170	1100–1240

How to use it

Set it. Set the dial to 960–1100. That is the light roast setting. Use the table above for anything darker.
Grind and look. You want pieces about the size of coarse sea salt.
Steep. Give it 18–22 hours in the fridge, or 12–14 on the counter.
Taste and adjust. Too bitter? Go coarser next time. Too sour? Go finer. Move about 140 at a time.

Let the app keep track.

Cold Brew Studio shows the dial created for your Zerno Z1 with the setting marked, sizes the batch to your brewer, and moves the dial for you when you rate how it tasted.

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Free on iPhone and the web. No account needed.

Quick answers

What grind setting should I use for cold brew on the Zerno Z1?: Start at 960–1100 for a light roast, 1030–1170 for a medium roast and 1100–1240 for a dark roast.
How long should I steep cold brew ground on the Zerno Z1?: 18–22 hours in the fridge for a light roast, 14–18 for medium and 10–14 for dark. On the counter it goes faster: 12–14, 9–12 and 7–9 hours.
What should the grounds look like?: Coarse. About the size of coarse sea salt for a light roast, coarse kosher salt for medium and raw sugar for dark.