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How to calibrate your coffee grinder, spot dull burrs, and know when to replace them for better flavor and smoother café workflow.
If your espresso shots have been acting moody lately, your grinder might be trying to tell you something. Grinder calibration and burr health are two of the biggest reasons shots swing from “perfect” to “uhh … what happened?” – and the fix is usually easier than people think.
A grinder isn’t just a machine that breaks beans apart. It’s the piece of equipment that controls how water extracts flavor from coffee. So when the grinder is off – even slightly off – your flavor, workflow, consistency, and speed all take a hit.
The good news? You don’t need special tools or an engineering degree to keep things working beautifully. You just need a basic understanding of how grinders behave, how burrs wear, and how to reset things when they drift.
This is your friendly, simple guide to:
Let’s get into it – gently, and clearly.
Grinder calibration sounds more complicated than it is. Let’s break it down:
Calibration = adjusting the grinder so it produces the grind size you want, on purpose, every day.
It’s basically pressing “reset” on your grinder so it behaves consistently, no matter what the weather is doing, what roast you’re using, or who’s working behind the bar.
Calibration keeps your espresso extraction stable, which keeps your flavor stable, which keeps your customers stable (emotionally).
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Okay – burr geometry can sound intimidating, but I promise this will be painless.
It’s the shape, angle, and cutting design of the grinder’s burrs.
Think of burr geometry like the personality of your grinder – it determines how the coffee breaks apart.
Flat burrs look like two flat plates facing each other.
They produce:
They’re a bit like scissors: very exact, very clean.
Conical burrs are shaped like a cone inside a ring.
They produce:
Think of them like a mortar and pestle – strong, forgiving, and cozy.
In many cafés:
Neither is “better.” They’re just different tools for different flavor goals.
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Let’s get practical. Calibration is easier when you follow a simple system.
You can’t calibrate through old coffee. It’s like trying to measure flour in a bowl that’s already full of flour.
Brush out the burr chamber. Remove retention. Check for oily buildup.
This part scares people, but it shouldn’t.
You won’t grind at zero – it’s just your reference point.
Move a little coarser than zero for espresso.
Move much coarser for filter coffee.
This is your baseline – not your final setting.
Use a simple recipe for consistency:
18g in → 36g out → 25–30 seconds
Adjust in tiny steps:
Small adjustments work best. Big swings create chaos.
Mark it. Log it. Share it.
Café life gets 10× easier when everybody starts from the same baseline.
Grinders drift. It’s normal. Here’s why:
Grinding warms the burrs. Warm burrs expand. Expanded burrs grind differently.
Coffee beans absorb moisture from the air – especially in tropical climates.
Wetter beans = slower shots.
Even the best burrs wear down.
As burrs dull, the grinder needs finer settings to get the same results.
Old oils can clog cutting edges and change how beans move through the burrs.
Light roasts, dark roasts, fresh beans, older beans – they all behave differently.
So if your grind keeps drifting, don’t panic. Your grinder isn’t misbehaving – it’s just reacting to physics.
“Throughput” = how much coffee you grind.
More coffee = faster burr wear.
(Source: SSP Grinding)
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If your café grinds about 3 kg/day, here’s what happens:
Burr lifespan varies by roast type too:
These are raw steel burrs with no protective layer on them.
Think of them as regular scissors: sharp at first, but they dull with time and friction.
These burrs are made of the same steel base but have an added coating (usually applied via PVD – physical vapor deposition).
Common coatings include:
Coated burrs are much tougher → they resist wear dramatically better.
Coffee passes through smoother → less heat → more consistent grind.
Coated burrs commonly last:
This is why high-volume cafés almost always prefer coated burrs.
You replace them far less often, and flavor stays consistent longer.
Worn burrs create more “fines” – tiny dust particles – which lead to:
Here are the most reliable “burr is wearing out” symptoms – easy to recognize, even for new baristas.
This is the classic dull-burr combo.
Dull burrs produce more fine dust → over-extracted flavors.
If your grind setting keeps creeping lower and lower, that’s burr wear speaking.
Overworked burrs get hot – and heat affects flavor.
Look for:
Inconsistent grind = inconsistent extraction.
Worn burrs lose stability and alignment.
Chips, worn teeth, shiny patches – replace them immediately.
A predictable schedule keeps your burrs happy.
Consistency beats perfection.
You don’t need much:
Your grinder affects flavor more than almost any other piece of equipment in your café. Keeping it calibrated – and knowing when burrs need replacing – saves time, reduces waste, improves consistency, and makes your drinks taste the way you meant them to taste.
With a little routine care, a gentle ear for calibration drift, and a logical replacement schedule, your grinder becomes a reliable, predictable partner in making great coffee.
And if you use Moqa, you can automate reminders for:
Your future self (and your baristas) will thank you.
Ready to see Moqa in action? Book a free demo today, or contact us to know more!
Daily for espresso. Weekly for filter.
When flavor drops, grind settings drift, or burr lifespan hits its rated limit (500–4,000 kg depending on material).
Yes – they make shots taste muddy, hollow, or flat.
Yep. Different beans → different grind behavior.
Not recommended. Most modern burrs are designed to be replaced.
